QCS 2014
Section 14: Roofing
Part
01: General
Page 1
1
GENERAL ...................................................................................................... 2
1.1
INTRODUCTION ........................................................................................... 2
1.1.1
1.1.2
1.1.3
Scope
References
Definitions
1.2
PREPARATION WORK ................................................................................. 4
1.2.1
1.2.2
General Requirements
Storage of Materials
1.3
GUARANTEE ................................................................................................ 4
1.3.1
General Requirements
1.4
PROTECTION ............................................................................................... 5
1.4.1
General Requirements
1.5
TESTING ....................................................................................................... 5
1.5.1
General Requirements
2
2
3
4
4
4
5
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5
QCS 2014
Section 14: Roofing
Part
01: General
Page 2
1
GENERAL
1.1
INTRODUCTION
1.1.1
Scope
1
This Section specifies general requirements for various types of roof covering materials and
accessories.
2
Related Sections are as follows:
Section 18
Section 15
Carpentry, Joinery and Ironmongery
Thermal Insulation of Buildings
1.1.2
References
1
The following standards are referred to in this Section:
TC
-------- Black paint (tar based)
-------- Wood wool cement slabs up to 125 mm thick
-------- Concrete flooring tiles and fittings
-------- Nails
-------- Wood screws
-------- Wrought aluminium and aluminium alloys for general engineering purposes:
Bars, extruded round tube and sections
BS 1494 -------- Fixing accessories for building purposes
BS 1521 -------- Water proof building papers
BS 3083 -------- Hot-dip zinc coated and hot-dip aluminium/zinc coats corrugated steel sheets
for general purposes
BS 3379 -------- Flexible polyurethane cellular materials for load bearing applications
BS 3416 -------- Bitumen based coatings for cold application, suitable for use in contact with
potable water
BS 3690 -------- Bitumens for building and civil engineering
BS 3797 -------- Lightweight aggregates for concrete
BS 3837 -------- Expanded polystyrene boards
BS 3869 -------- Rigid expanded polyvinyl chloride for thermal insulation purposes and
building applications
BS 3927 -------- Rigid phenolic foam (PF) for thermal insulation in the form of slabs and
profiled sections
BS 4016 -------- Building papers (breather type)
BS 402 ---------- Clay plain roofing tiles and fittings
BS 4154 -------- Corrugated plastic translucent sheets made from thermo-setting polyester
resins (glass fibre reinforced)
BS 4841 -------- Rigid polyurethane (PUR) and polyisocyanurate (PIR) form for building
applications
BS 4868 -------- Profiled aluminium sheet for building
BS 5075 -------- Concrete admixtures
BS 5284 -------- Methods of sampling and testing mastic asphalt used in building and civil
engineering
BS 5534 -------- Code of Practice for slating and tiling
BS 6229 -------- Flat roofs with continuously support coverings
BS 6515 -------- Polyethylene damp-proof courses for masonry
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BS 1070
BS 1105
BS 1197
BS 1202
BS 1210
BS 1474
QCS 2014
Section 14: Roofing
Part
01: General
Page 3
BS 6676 -------- Thermal insulation of cavity walls using man-made mineral fibre batts (slabs)
BS 680 ---------- Roofing slates
BS 747 ---------- Roofing felts
BS 8000 -------- Workmanship on Building Sites
BS 812 ---------- Testing aggregates
BS 8217 -------- Code of Practice for built-up felt roofing
BS 882 ---------- Aggregates from natural sources for concrete
BS EN 485 ----- Aluminium and aluminium alloys – Sheet, strip and plate
BS EN 490 ----- Concrete roofing tiles and fittings-product specifications
BS EN 491 ----- Concrete roofing tiles and fittings-test methods
BS EN 538 ----- Clay roofing tiles for discontinuous laying-flexural strength test
BS EN 539 ----- Clay roofing tiles for discontinuous laying-determination of physical
characteristics.
EN 197-1 ------- Portland cement
1.1.3
Definitions
1
For purposes of this Section, certain terms are designated in the following paragraphs:
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BASE SHEET is one layer of felt or combination sheet secured to the deck over which may
be applied additional felts, a cap sheet, organic or inorganic fibre shingles, smooth coating or
mineral aggregate.
AM
BUILT-UP ROOF COVERING is two or more layers of roofing consisting of a base sheet,
felts and cap sheet, mineral aggregate, smooth coating or similar surfacing material
CAP SHEET is roofing made of organic or inorganic fibres, saturated and coated on both
sides with a bituminous compound, surfaced with mineral granules, mica, talc, ilmenite,
inorganic fibres or similar materials
CEMENTING is solidly mopped application of asphalt, cold liquid asphalt compound, coal tar
pitch or other approved cementing material
COMBINATION SHEET is a glass fibre felt integrally attached to kraft paper
CORROSION-RESISTANT is any non-ferrous metal or any metal having an unbroken
surfacing of non-ferrous metal, or steel with no less than 10 % chromium or with not less than
0.20 % copper
FELT is matted organic or inorganic fibres, saturated with bituminous compound
FELT, NONBITUMINOUS SATURATED is matted asbestos fibres with binder for use with
wood shingle and wood shake assemblies
GLASS FIBER FELT is a glass fibre sheet coated on both sides with bituminous compound
INTERLAYMENT is a layer of felt or non-bituminous saturated asbestos felt not less than 450
mm wide, shingled between each course of roof covering
INTERLOCKING ROOFING TILES are individual units, typically of clay or concrete,
possessing matching ribbed or interlocking vertical side joints that restrict lateral movement
and water penetration
QCS 2014
Section 14: Roofing
Part
01: General
Page 4
METAL ROOFING is metal shingles or sheets for application on solid roof surfaces, and
corrugated or otherwise shaped metal sheets or sections for application on solid roof
surfaces or roof frame works
NON-NAILABLE DECK is any deck, which is incapable of retaining an approved fastener
PREPARED ROOFING is any manufactured or processed roofing material, other than
untreated wood shingles and shakes, as distinguished from built-up coverings
SPOT CEMENTING is discontinuous application of asphalt, cold liquid asphalt compound,
coal tar pitch or other approved cementing material
UNDERLAYMENT is one or more layers of felt or non-bituminous saturated asbestos felt
over which the finish roofing is applied.
PREPARATION WORK
1.2.1
General Requirements
1
Before commencing installation of the roof, waterproofing and insulation system all
construction work and installations above roof level are to be completed as far as possible.
Particular care is to be taken to ensure:
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1.2
all rainwater, plumbing, air-conditioning and ventilation duct outlets have been fixed in
position and are protected against blockage or accidental damage
(b)
supports to ductwork, pipework, cable trays and the like have been installed
(c)
all kerbs to roof lights, access doors, plant and water tanks have been installed
(d)
all chases for skirtings, etc., have been prepared.
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(a)
2
The surface of the roofing substructure is to be clean and dry, free from ridges or
indentations, laid to falls as required and not contaminated with oil or other deleterious
matter.
3
No waterproofing membrane is to be applied until the roofing substructure has been
inspected and approved by the Engineer.
1.2.2
Storage of Materials
1
Polystyrene insulation boards are to be protected against prolonged exposure to sunlight.
2
Blanket type insulation is to be protected from moisture.
1.3
GUARANTEE
1.3.1
General Requirements
1
The Contractor is to provide the Engineer with a seven (7) year unconditional guarantee
against failure of the roof waterproofing system whether caused by defective materials or
workmanship. The guarantee should be valid from the date of completion of the installation
and must be provided to the Engineer in accordance with Section 1, General.
QCS 2014
Section 14: Roofing
Part
01: General
Page 5
1.4
PROTECTION
1.4.1
General Requirements
1
Adequate protection against damage to the roof waterproofing system is to be provided
where further construction work is necessary in the area.
1.5
TESTING
1.5.1
General Requirements
1
On completion of application of new roof waterproofing material to an existing roof but before
application of insulation and protection, the Contractor shall seal off all rainwater outlets and
flood the roof to a depth of 25mm. After 48 hours, visual inspection of the roof shall be
undertaken from inside the building in the presence of the Engineer's Representative to
establish that there are no leaks in the structure. The Contractor shall make up any loss of
water during the test due to either evaporation or leakage. The Contractor shall be
responsible for the locating and sealing of any leaks found. The test shall be repeated, at the
Contractor's expense, until no leaks exist.
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TC
END OF PART
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 1
MEMBRANE ROOFING ................................................................................ 2
2.1
GENERAL ...................................................................................................... 2
2.1.1
2.1.2
2.1.3
Scope
References
General Description of Workmanship
2.2
BUILT-UP BITUMINOUS FELT ROOFING.................................................... 3
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
2.2.9
2.2.10
2.2.11
2.2.12
General Requirements
Delivery, Storage and Marking
Materials
Execution of Work
Surface Preparation
Existing Roofs and Repair Areas
Installation of Built-Up Roofing Membrane
Base Flashing
Stripping
Roof Pour Coat and Aggregate
Roof Walkways
Alterations to Existing Roofs
2.3
COLD APPLIED BITUMINOUS COATING .................................................. 12
2.3.1
General Requirements
2.4
PREPARED ROLL ROOFING ..................................................................... 13
2.4.1
General Requirements
2.5
MODIFIED BITUMINOUS SHEET ............................................................... 13
2.5.1
General Requirements
2.6
SINGLE LAYER MEMBRANE ..................................................................... 13
2.6.1
General Requirement
2.7
FLUID APPLIED MEMBRANES .................................................................. 13
2.7.1
2.7.2
General Description
Liquid Applied Waterproofing Systems
2.8
COATED SPRAY APPLIED FOAM ............................................................. 15
2.8.1
2.8.2
Description
Installation
2.9
PERMEABLE FILTER MEMBRANE ............................................................ 15
2.9.1
General Requirements
2.10
PROTECTED MEMBRANE ......................................................................... 15
2.10.1 General Requirements
2.11
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2
2
2
3
3
3
4
5
8
8
8
10
11
11
11
11
12
13
13
13
14
14
15
15
15
16
TORCH APPLIED WATERPROOF MEMBRANE ....................................... 16
2.11.1 General Requirements
16
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
2
MEMBRANE ROOFING
2.1
GENERAL
2.1.1
Scope
1
This Part specifies requirements for flexible roof coverings of various types.
2
Related Sections are as follows:
Section 5
Section 15
Section 18
Page 2
Concrete
Thermal Insulation of Buildings
Carpentry, Joinery and Ironmongery
2.1.2
References
1
The following standards are referred to in this Part:
ASTM D412 - 06ae2 Standard Test Methods for Vulcanized Rubber and Thermoplastic
Elastomers—Tension
ASTM D1227 ..............Standard Specification for Emulsified Asphalt Used as a Protective
Coating for Roofing
ASTM D2240 ..............Standard Test Method for Rubber Property—Durometer Hardness
ASTM E96 ..................Standard Test Methods for Water Vapor Transmission of Materials
AM
TC
ASTM G154................Standard Practice for Operating Fluorescent Light Apparatus for UV
Exposure of Nonmetallic Materials
BS 747 ........................Specification for roofing felts
BS 812 ........................Testing aggregates
BS 882 ........................Aggregates from natural resources
BS 1070 ......................Black paint (tar based)
BS 1197 ......................Concrete flooring tiles and fittings
BS 1202 ......................Nails
BS 1210 ......................Wood screws
BS 1494 ...................... Fixing accessories for building purposes
BS 1521 ......................Waterproof building papers
BS 3416 ...................... Bitumen based coatings for cold application, suitable for use in
contact with potable water
BS 3690 ......................Bitumens for building and civil engineering
BS 4016 ......................Building papers (breather type)
BS 5284 ...................... Methods of sampling and testing mastic asphalt used in building and
Civil Engineering
BS 6229 ......................Flat roofs with continuously supported coverings
BS 6920 ......................Suitability of non-metallic products for use in contact with water
intended for human consumption with regard to their effect on the
quality of the water
BS 7263 ......................Pre-cast concrete flags, kerbs, channels, edgings and quadrants
BS 8000 ......................Workmanship on Building Sites
BS 8217 ......................Code of practice for built-up felt roofing
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 3
General Description of Workmanship
1
The roof coverings are not to be applied to a damp base and care is to be taken to ensure
that no moisture is trapped between successive layers.
2
Skirtings are to be a minimum of 150 mm above the roof finish at any point.
3
Protective finishes and surface treatments are to be applied as soon as possible after
completion of the roof coverings.
4
Projections passing through the roof covering are to be provided with hoods or caps to permit
the roof covering to terminate beneath the hood and be protected by it from weather
elements.
5
Outlets for surface water, whether in gutters or roof areas, are to be set slightly below the
adjacent roof surface and be suitably flashed to allow a bonded lap of roofing felt and flashing
material of 100 mm (minimum).
6
Roof waterproofing materials shall be applied by specialist personnel or a specialist subcontractor having previous experience of the system and approved by the Engineer's
Representative. The specialist sub-contractor shall provide the guarantee specified in Part 1
of this Section in favour of Public Works Authority.
7
On completion of application of waterproofing material to an existing concrete roof but before
the application of insulation and protection, the Contractor shall seal off all rainwater outlets
and flood the roof to a depth of 25mm. The Contractor shall make up any loss of water due to
evaporation or leaks. After 48 hours, visual inspection of the roof shall be undertaken from
inside the building in the presence of the Engineer’s Representative to establish if there are
any leaks in the structure. The Contractor shall locate and seal any leaks. The test shall be
repeated at the Contractor’s expense until no leaks exist.
8
On new roofs the test detailed in sub-clause 7 shall be carried out prior to application of
lightweight screed and waterproofing membrane.
2.2
BUILT-UP BITUMINOUS FELT ROOFING
2.2.1
General Requirements
1
This section specifies built-up bituminous felt roofing on new roofs and for repairs to existing
roofs.
2.2.2
Delivery, Storage and Marking
1
Roofing materials shall be delivered to the Site in original sealed packages or containers
marked with the name and brand, or trademark of the manufacturer or seller.
2
Roofing materials shall be kept dry and stored in weathertight facilities or under canvas tarps.
Use of polyethylene or plastic tarps to cover materials is not permitted. Roofing materials
shall be stored above ground or deck level on wood pallets. Ground under stored materials
shall be covered with a plastic cover.
3
Rolled materials (felts, base sheets, paper) shall be stored on end. Materials shall not be
stored on top of rolled materials.
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2.1.3
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 4
4
Aggregate are to be maintained in a surface dry condition as defined by BS 812 and BS 882.
5
Materials shall be protected from damage from handling, weather and construction
operations before, during, and after installation.
2.2.3
Materials
1
Built-up bituminous materials are to conform to applicable Standards listed in Clause 2.1.2.
2
Asphalt materials (general) include:
4
primer
(b)
organic felt
(c)
asphalt
(d)
glass reinforced felt
(e)
venting asphalt base sheet
(f)
mineral surface roll roofing
(g)
roof cement
(a)
primer
(b)
organic felt
(c)
coal-tar bitumen
(d)
roof cement
Miscellaneous component requirements are as follows:
(a)
(b)
(c)
5
TC
Coal tar materials include:
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3
(a)
aggregate requirements include:
(i)
aggregates to comply with requirements of BS 882.
(ii)
chippings are to be approved, clean, crushed white or pale grey aggregate size
15 to 30 mm.
(iii)
(rounded gravel shall e free of sharp angular or broken pieces.
roof walkway requirements include:
(i)
prefabricated asphalt plank consisting of a homogeneous core or asphalt,
plasticizers and inert fillers, bonded by heat and pressure between two saturated
and coated sheets of felt. The top side of planks shall be surfaced with ceramic
granules.
(ii)
concrete masonry paving units shall comply with BS 1197 and BS 7263.
building paper (sheating paper) shall comply with BS 1521 and BS 4016.
Fasteners to be used include the following:
(a)
nails and staples shall comply with BS 1210 and BS 1202
(b)
nails for securing built-up flashing and base sheets to wood deck shall be either:
QCS 2014
(c)
Section 14: Roofing
Part
02: Membrane Roofing
Page 5
(i)
zinc coated steel roofing nails with a minimum head diameter of 9 mm through
metal discs at least 25 mm across
(ii)
one piece nails with an integral flat cap at least 24 mm across.
fasteners for securing building paper and dry felt edge strips to wood nailer and decks
shall be either:
(i)
zinc coated steel roofing nails with a minimum head diameter of 16 mm
(ii)
flat top crown, zinc coated staples
(d)
nails for plywood are to be annular thread type and shall penetrate plywood by at least
19 mm
(e)
nails for securing built-up flashing to masonry shall be either:
(i)
hardened steel nails through metal discs at least 25 mm in diameter
(ii)
one piece nails with an integral flat cap at least 24 mm across.
nails for securing venting base sheet to insulating concrete shall be galvanized steel
self-clinching type having a integral flat cap at least 25 mm across. They are to have a
holding power of not less than 130 kg when pulled from approximate dense concrete
(g)
nails for securing base sheet, building paper, or first layer of vapour retarder to
structural wood fibre decks shall be the self-clinching type having an integral flat cap
not less than 25 mm across. They are to have a holding power of not less than 85 kg
per fastener
(h)
nails for securing base sheet to poured gypsum roof deck shall be specially shaped
nails providing a diverging or hooking point. They shall have a flat cap not less than 32
mm across and have a withdrawal resistance of not less than 85 kg per fastener.
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TC
(f)
2.2.4
Execution of Work
1
Roofing materials shall not be applied if the deck will be used as a subsequent work platform,
for storage of materials, or if staging or scaffolding will be erected thereon.
2
The entire roof deck construction of any section of the building is to be completed before
roofing work is begun including:
(a)
installation of curbs, blocking, edge strips, fillets, and other components where
insulation, roofing and base flashing is attached shall be in place ready to receive
insulation and roofing
(b)
co-ordination of roof operations with roof insulation and sheet metal work so that
insulation and flashing is installed concurrently to permit continuous roofing operations.
3
Roofing materials are to be dry when applied.
4
Surfaces, including the flutes of metal deck, that become wet from any cause during
progress of the work shall be dried out before roofing work is resumed. Materials shall only
be applied to dry substrata.
5
Except for temporary protection, materials shall not be applied during damp or rainy weather,
during excessive wind conditions, nor while moisture (dew or fog) is present in any
amount in or on the materials to be covered or installed.
6
Materials shall not be applied when the temperature is below 10 ºC.
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 6
7
Phased construction is not permitted. The installation of all layers is to be completed
in the same day, including insulation, base flashings, and the layers surfaced with
either the flood coat and aggregate or with a glaze coat except for the area where
temporary protection is required when work is stopped.
8
Temporary protection shall comply with the following requirements:
(b)
glaze coat all exposed surfaces of felts to seal in the bitumen coating. No felt surfaces
or edges are to be left exposed
(c)
install temporary cap flashings over the top of base flashings where permanent
flashings are not in place. Temporary cap flashings are to provide complete protection
against moisture entering the roof system through or behind the base flashing.
Securely anchor in place to prevent blowing off and damage by construction activities
(d)
provide for removal or drainage of water away from the work
(e)
provide temporary protection for roofing by means of duckboard walkways, plywood
platforms, or other materials, as approved by the Engineer, for roof areas that are to
remain intact, and that are subject to foot traffic and damage.
(f)
provide notches in sleepers to permit free drainage.
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install temporary protection consisting of glazed coats and water cut-offs at the end of
each day’s work and when the work is halted for an indefinite period or work is stopped
when precipitation is imminent
Heating of bitumen for installation of roofing shall comply with the following requirements:
(a)
heat the asphalt to the equiviscious temperature 1 °C; at the time of application
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(a)
asphalt should not be heated greater than 35 °C above the equiviscous temperature
10
11
(b)
coal-tar bitumen is not to be heated above 215 °C with an application temperature
ranging from 160 °C to 200 °C
(c)
at no time should bitumen be heated above the flash point temperature
(d)
provide heating kettles with a thermometer kept in operating condition at all times.
Kettlemen are to be in attendance at all times during heating to insure that the
bitumens are heated within the temperatures specified.
Asphalt or coal-tar products shall be used, except as specified below:
(a)
use asphalt only with asphalt-saturated or asphalt-impregnated felts
(b)
use coal-tar pitch and coal-tar-saturated felts in conjunction with coal-tar roofing
(c)
Asphalt-saturated felts may be used for flashings.
Installation of roofing materials with hot bitumen shall comply with the following requirements:
(a)
apply bitumen in quantities required, immediately followed by felts or other materials to
be embedded therein before bitumen cools below the application temperature limit
(b)
do not apply more material than can be covered at one time
(c)
re-coat cooled bitumen areas with hot bitumen
(d)
roll felts into bitumen, rolling, squeezing or brushing down to firmly embed in the hot
bitumen free of wrinkles, blisters, bubbles, voids, air pockets or other defects that
prevent complete adhesion. Use squeegees only on glass felts
QCS 2014
12
Section 14: Roofing
Part
02: Membrane Roofing
Page 7
(e)
felts shall be lapped shingle fashion for the number of layers specified starting with
starter strips at right angles to slope of roof
(f)
the laying of the roofing materials should commence at the low points
(g)
bitumen is to separate all felts or substrata so that subsequent layers do not touch
previous placed layers of felt or substrata unless noted specifically
(h)
cut the felt to fit closely around pipes, roof drains, bitumen stops, and similar roof
projections.
Laps for felts and base sheet shall be as follows:
(a)
base sheet shall be lapped 75mm
(b)
two layers of felt with 500 and 900 mm starting widths shall be lapped 600 mm
(c)
three layers of felt with 300, 600 and 750 mm starting widths shall be lapped 600 mm
(d)
four layers of felt with 225, 500 mm and 750 starting widths shall be lapped 700 mm.
13
Primer shall be applied with 3.5 litres of primer per 10 m2 of surface area unless otherwise
recommended by the manufacturer and approved by the Engineer.
14
Quantities of bitumen used shall be as follows:
(b)
asphalt, 33 to 55 kg/m
(ii)
coal tar, 44 to 66 kg/m
(d)
15
2
between substrata and layers of glass fibre felts
(i)
(c)
2
(i)
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between substrata and layers of organic felt:
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(a)
asphalt, 9 to 13 kg/m
2
glaze coats:
2
(i)
asphalt, 33 to 55 kg/m
(ii)
coal tar, 44 to 66 kg/m
2
pour or flood coats:
2
(i)
asphalt, 122 to 144 kg/m
(ii)
coal tar, 155 to 177 kg/m
2
Nailing or anchorage of felts or base sheets to nailable decks shall include the following
requirements:
(a)
nails or fasteners appropriate for type of deck to be covered shall only be used.
(b)
two layers of felt shall be laid as follows:
(c)
(i)
nail down both layers along bottom edges at intervals not to exceed 225 mm
(ii)
nail down both layers at both edges at intervals not to exceed 225 mm
anchorage of base sheets shall be as follows:
(i)
nail along laps and edges at intervals not to exceed 225 mm with end and edge
laps solidly sealed with roof cement
(ii)
stagger nails down centre of sheet in two rows 300 mm apart at intervals of not
more than 500 mm in each row.
QCS 2014
16
Section 14: Roofing
Part
02: Membrane Roofing
Page 8
Building paper shall be laid as follows:
(a)
lay paper smoothly without buckles or wrinkles at right angles to the roof slope starting
at the low point
(b)
lap each sheet of paper at least 50 mm over proceeding sheet, and at the ends
(c)
staple or nail sufficiently to hold in place until the roofing is installed.
2.2.5
Surface Preparation
1
Sweep decks and remove all dust, dirt and debris.
2
Remove projections that might penetrate or damage roofing felt materials.
3
Preparation of concrete decks, (except insulating concrete) for installation of roofing shall
comply with the following requirements:
test concrete decks for moisture prior to application of roofing materials. Heat
bitumen as specified and pour approximately 0.5 litres of bitumen on surface to which
roofing materials are to be applied. If bitumen foams upon contact with the deck or if
after bitumen has cooled and bitumen is stripped from deck leaving no residue, the
deck is not dry enough for application of prime coat or roofing
(b)
prime concrete decks, including precast units, with primer as recommended by the
manufacturer for certification. Keep the primer 100 mm back from the joints in precast
units
(c)
allow primer to dry before application of bitumen.
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TC
(a)
4
Roof surfaces of wood sheathing, gypsum, gypsum plank and cement wood fibre plank shall
be covered with a layer of building paper.
2.2.6
Existing Roofs and Repair Areas
1
Where new penetrations occur and in areas where repairs are required, loose aggregate and
aggregate that is not firmly embedded shall be removed.
2
Where new work to be installed, the existing membrane should be cut out and removed and
a temporary seal to cut surfaces installed. The temporary seal shall consist of roof cement
and one layer of 33 kg/m2 glass fibre felt or fabric strip. The glass fibre felt or fabric strip shall
extend 150 mm on each side of cut surface and shall be completely embedded in the roofing
cement.
3
If the existing built-up base flashing is to be repaired, either bend up the cap flashing or
temporarily remove the cap flashing. Brush and scrape away all deteriorated and loose
bitumen, felts, or surface material of built-up base flashing, and repair as necessary in
accordance with the requirements of this Section.
4
A venting base sheet shall be used over all insulating concrete and poured gypsum decks to
relieve possible vapour pressures that may occur.
5
The same bitumen shall be used for roof repairs and alterations as used in the existing
roofing construction.
2.2.7
Installation of Built-Up Roofing Membrane
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 9
1
The built-up roofing membrane is to be aggregate surfaced, three layer, glass fibre felt
construction using asphalt or four layer organic felt and coal tar bitumen. Building paper or a
base sheet is not considered as a layer.
2
General requirements of installation of built-up roofing membrane are as follows:
where nailers occur at roof edges under gravel stops or penetrations to receive metal
base flashing, nail a continuous strip of 400 mm wide dry organic felt envelope over
the nailers before the first layer sheet is applied. The organic felt strip is to be installed
on top of the venting base sheet. After the membrane is installed, turn the dry felt back
over the roofing, and secure in place with hot bitumen before gravel stops or other
metal flanges extending out onto the membrane are installed
(b)
where fillets occur at vertical surfaces, cut off layers of the membrane 50 mm above,
the top of fillet strips. At prefabricated curbs, scuttles and other roof accessories
having integral fillets, extend the membrane over the fillet and up the
vertical surface to the top of the curb or nailer as shown in drawings
(c)
where a fascia-fillet occurs at the roof edges, extend the membrane beyond the
outside fillet face and cut off at the outside after the base flashing is installed. Do not
cut off the venting base sheet outside the fillet face, extend it down over the outer fillet
face to allow for venting
(d)
where a recessed flashing occurs at vertical surfaces, extend layers of roofing up into
recessed flashing the full depth of the recessed flashing.
TC
(a)
Built-up roofing installed over on insulation shall be sealed down as specified Clause 2.2.7-3.
4
Built-up roofing installed on concrete and precast concrete Units shall comply with the
following requirements:
5
AM
3
(a)
prime deck as specified Clause 2.2.4-13
(b)
keep bitumen back 100 mm from joints in precast units
(c)
seal down membrane as specified Clause 2.2.4.
Built-up roofing installed on nailable decks shall include requirements as follows:
(a)
on insulating concrete decks, install one layer of venting base sheet with the mineral
aggregate surface down. Fasten base sheet to deck as required, followed by
membrane as specified
(b)
termination venting base sheet:
(c)
(i)
at vertical surfaces: extend venting base sheet up vertical surface over fillets
to top of base flashing or curb
(ii)
at the roof edges under gravel stops install a venting base sheet over the
blocking. The base sheet shall be extended not less than 50 mm beyond the
outer edge and it shall be turned down so that venting can be accomplished
(iii)
at the roof edge over a fascia-fillet: extend the base sheet over the top of the
fillet and turn it down over the outer face of the fillet to permit venting at the
edge.
on poured gypsum, precast gypsum plank, cement-wood fibre plank, wood plank or
plywood decks, install one layer of building paper followed by either:
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 10
(i)
two layers of 33 kg organic felt laying both layers down dry to deck except to
seal between laps. Lap and nail as specified to deck. Follow immediately by the
membranes sealed down to the felt
(ii)
one layer of base sheet or venting base sheet. Lay base sheet down dry on
the deck. Lap as specified and seal the edge laps with roofing cement. Nail
as specified followed by the roofing membrane sealed down to the base
sheet.
Cover the exposed surface of the last layer of felt, except on fillets and under concrete
pavers or runners of wood roof walkways, with bitumen and aggregate as specified.
2.2.8
Base Flashing
1
Provide built-up base flashings over fillets and wherever necessary to make the work
watertight.
2
Install flashing before final bituminous coat and roof aggregate is installed.
3
Prime vertical surfaces of masonry and concrete with asphalt primer except where the
vented base sheet is required to provide edge venting.
4
When applying a flashing on top of built-up roofing, up the face of fillets and up the face of
the vertical surfaces, between 200 mm and 300 mm above the built-up roofing, the following
shall apply:
5
6
TC
6
at fascia-fillets, extend the flashing to the top of fillet and cut off at the top of fillet
(b)
at recessed flashings, extend the flashing full depth into the recessed flashing
(c)
where venting base sheet is used with insulating concrete, do not seal edges of
venting base sheet with bitumen in order to allow for venting.
AM
(a)
Flashing is to consist of two layers of 33 kg/m2 glass fibre felt or fabric, surfaced capped as
specified.
(a)
extend the first layer of flashing 100 mm out on the roofing, and the second layer of
flashing 75 mm beyond the first layer. Lap ends 75 mm with joints broken 500 mm in
each layer
(b)
cap sheet is to be mineral surfaced roll roofing or modified bitumen sheet extending
from toe of fillet to top of base flashing. Lap the ends 75 mm with joints not coinciding
with joints in under layers.
Base flashings may be set either in asphalt (hot applied method) or in roof cement (cold
applied method), with only one method only used throughout. Application of either method
shall be as follows:
(a)
(b)
cold applied method:
(i)
embed each layer of flashing in roof cement so layers do not touch felt
(ii)
cover the last layer of flashing with a troweled on coat of the roof cement, into
which embed the cap sheet from toe of the fillet to top of the base flashing and
seal laps with roof cement
(iii)
Use cold applied method with coal tar roofing.
hot applied method:
QCS 2014
(c)
Section 14: Roofing
Part
02: Membrane Roofing
Page 11
(i)
embed each layer of flashing and cap sheet in asphalt so that the layers do not
touch
(ii)
set the cap sheet in hot bitumen with laps sealed with hot bitumen.
except for venting roof edges, seal the top edge of the base flashing with roof cement.
Except at metal fascia fillets, secure top edge of the base flashing with nails on a line
approximately 25 mm below the top edge, and at not more than 200 mm centres. All nail
heads shall be covered with roof cement. The top of the base flashing shall be covered with
counter flashing. At fascia fillets, secure the top edge of the flashing with fascia compression
clamps.
2.2.9
Stripping
1
Before the final bituminous coat and roof aggregate is installed, cover that portion of the
horizontal flanges of metal base flashings, gravel stops, and other flanges extending out onto
the roofing with a composition flashing consisting of two layers of glass fibre felt or fabric.
Use organic felt with coal tar bitumen for stripping.
2
Extend the first layer of flashing out on the roofing 100 mm beyond the edge of the flange
and the second layer 75 mm beyond the edge of the first layer. Cut edges to fit tight against
vertical members of the protruding flange.
3
Each layer of flashing shall be embedded in hot bitumen or roofing cement.
2.2.10
Roof Pour Coat and Aggregate
1
After bituminous base flashing and stripping have been installed uniformly coat the entire roof
surface except fillets with hot asphalt or coal-tar bitumen poured on, as directed in Clause
2.2.4 of this Part.
2
While still hot, embed necessary amount of aggregate to cover the roofing felt completely
without bare spots, but not less than 888 kg/m2 of dry gravel or 666 kg/m2 of dry slag. The
aggregate cover shall be such that no bitumen is left exposed.
3
Placing the aggregate material in piles or rows on bare or glaze coated felt before placement
is prohibited.
2.2.11
Roof Walkways
1
Walkways may be concrete masonry units or prefabricated asphalt planks.
2
Place concrete masonry units on top of the pour coat. Aggregate shall not be embedded
under runners of wood roof walkways. Butt concrete masonry units to provide a continuous
walkway surface.
3
When prefabricated asphalt planks are used, sweep away loose roof aggregate from the
areas to receive planks. Set the planks in hot bitumen poured over the firmly embedded roof
aggregate as specified for pour coat. Maintain a minimum of 75 mm to a maximum of 150
mm space between planks.
2.2.12
Alterations to Existing Roofs
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QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 12
1
Roof repair and alteration work is to match existing roofing material and construction.
Bitumen compatible with the existing bitumen shall be used for roof repair and alterations.
2
Make cut-outs of existing roof system to confirm the condition of the roof. Cuts are to be
made in the presence of the Engineer in locations as directed by the Engineer. Each cut-out
opening shall be photographed. The cut-out area shall be repaired immediately upon
confirmation of the condition of the roof. Any moisture found in the roof membrane or
insulation shall be reported to the Engineer.
3
Repairs to existing membrane and base flashing shall be carried out as follows:
(a)
remove temporary patches prior to starting repair work
(b)
blisters and fish mouths:
(d)
(e)
(f)
(ii)
heat membrane to facilitate bending and to dry out surface of blistered areas
exposed
(iii)
seal down turned back membrane in hot bitumen. Roll to insure full adhesion
and embedment in substrata
(iv)
cover cut areas with two layers of felt. Extend first layer 100 mm beyond cut
area edge. Extend second layer 100 mm beyond first layer. Seal down in hot
bitumen as specified for new work. Resurface as specified.
TC
cut blisters open and turn membrane back to fully adhered portion. Cut fish
mouth so membrane can be turned back and subsequently laid flat
exposed felts:
AM
(c)
(i)
(i)
cut away exposed deteriorated edges of organic felt
(ii)
glaze coat felt edges
(iii)
resurface as specified.
built-up base flashing:
(i)
restore felts and cap sheet removed, lapping 100 mm over existing remaining
(ii)
install new felts and cap sheet as specified for new work.
horizontal metal flanges:
(i)
remove loose, buckled, or torn stripping
(ii)
remove loose fasteners and install new fasteners
(iii)
restrip flanges as specified for new work.
resurfacing:
(i)
over repaired membrane, re-pour and embed new or cleaned aggregate as
specified for new work
(ii)
cover all membrane areas. Do not leave any exposed membrane surface.
2.3
COLD APPLIED BITUMINOUS COATING
2.3.1
General Requirements
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 13
The Contractor is to clean and prepare roofing surface areas immediately prior to application
of bitumen coating. Black bitumen coating solutions to be applied in accordance with BS
3416, BS 6920.
2
Application of cold applied bituminous solution is to be done by a qualified experienced
personnel.
3
All openings and roof vents are to have watertight flashings.
2.4
PREPARED ROLL ROOFING
2.4.1
General Requirements
1
Prepared roll roofing is the top layer in a built-up roofing membrane. Standard prepared roll
roofing material consists of a glass fibre mat coated on both sides with a stabilised asphalt
coating and surface coated with non-combustible ceramic granules.
2
Prepared roll roofing material is to be compatible with, and manufactured by the supplier of,
the built up roofing membrane.
3
Prepared roll roofing is to be sealed with hot bitumen or cold adhesive as recommended by
manufacturer.
4
The Contractor shall guarantee roll roofing for fifteen (15) years.
2.5
MODIFIED BITUMINOUS SHEET
2.5.1
General Requirements
1
Modified bituminous sheet is a cold applied membrane composed primarily of modified
bituminous material prefabricated in sheet form.
2
Modified bituminous sheet is reinforced with glass fibre, polypropylene, or polyester fabric
which may be bonded to a plastic sheet, and supplied in this form by the manufacturer.
3
The standard sheet thickness shall be 4 mm.
4
The sheet is to be provided with a release sheet to prevent bonding of the sheet to itself.
2.6
SINGLE LAYER MEMBRANE
2.6.1
General Requirement
1
A single layer membrane is a 4mm (minimum) single layer bituminous felt membrane and is
torch applied.
2
Overlaps in the applied membrane are to be in the same direction as the roof slope.
3
Base flashing items as specified in Clause 2.2.8 of this part are to be completed prior to the
installation of the single layer membrane.
2.7
FLUID APPLIED MEMBRANES
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1
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 14
2.7.1
General Description
1
Liquid applied membranes shall be non-aqueous and should consist of a one component
high quality polyurethane elastomeric coating or a two component coal tar polyurethane
elastomer.
2
If polyurethane elastomeric coating is used then it shall cure by reacting with the humidity to
form an elastic strong film with excellent adhesion to different substrate.
3
Elastomeric waterproofing liquid membrane shall have the minimum following properties or
equivalent standards:Tensile Strength, ASTM D412:
Elongation, ASTM D412:
Shore A, ASTM D2240:
Vapor transmission, ASTM E96:
QUV accelerated weathering test, ASTM G154:
Service Temperature:
If two component coal tar polyurethane elastomer used then it shall cure, when mixed, to
form a flexible, elastomeric waterproof membrane having the following minimum properties
after ageing:
2
AM
Tensile strength:
Elongation:
Shore Hardness:
Total Solids:
Moisture vapour transmission:
TC
4
> 5 N/mm²
> 500 %
> 70
0.8 gr/m²
(2000hrs) Passed
o
-40 to 80 C
4.0 N/mm .
300-400 %
I.R.H.D. 70 %.
90-95 %
2
8.5 ml/m /24 hours
5
The waterproofing membrane is to incorporate the sealer/primer, reinforcing and reflective
coating materials recommended by the manufacturer of the membrane.
6
The Contractor is to submit to the Engineer the manufacturer’s literature concerning the shelf
life of each component material of the system to be used, together with authoritative
evidence of the dates of production
2.7.2
Liquid Applied Waterproofing Systems
1
Surfaces receiving the waterproof membrane are to be treated with the recommended
primer. sealer and allowed to dry.
2
When all the surfaces receiving the membrane and the equipment to be used are ready, the
materials are to be mixed in strict accordance with the manufacturer’s instructions using a
mechanical mixer. Only that amount which can be used within the pot life of the material is to
be prepared.
3
Reinforcing strips at construction and movement joints, shrinkage cracks, pipe inlets/outlets,
electrical conduit, air-conditioning ducting etc., must be applied in the widths and thickness
recommended by the manufacturer prior to final applications of the membrane.
4
When the reinforcing strips and expansion joint covers have cured, the membrane is to be
applied using an airless spray, trowel, squeegee or any other recommended method
producing the required membrane thickness.
QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 15
Site operatives are to be kept off the membrane until it has cured sufficiently to accept foot
traffic. Tackiness of the surface may be neutralised by dusting with dry cement. Areas where
labourers will be working applying topping materials should be covered with a protective layer
of fibreboard.
6
Surfaces which are not to receive a permanent protective covering are to be treated with a
solar reflective finish recommended by the manufacturer of the membrane.
2.8
COATED SPRAY APPLIED FOAM
2.8.1
Description
1
This Clause specifies general requirements for spray applied foam insulation which is
covered with a protective coating.
2.8.2
Installation
1
Prior to spray application of the foam all welding or other hot work required on the roof is to
be completed and all surfaces not to receive the insulation are to be securely wrapped or
otherwise protected with suitable covering.
2
The equipment used by the Contractor is to provide thorough mixing of components and be
calibrated prior to commencing work to ensure correct metering of the material components.
3
Under no circumstance should spraying be carried out in the presence of water or when the
wind speed is in excess of 25 kilometres per hour.
4
The foam to be applied in minimum 12 mm layers to build up the specified thickness.
5
The first coat or layer of the protective covering is to be applied the same day the foam
insulation is installed.
6
If for any reason more than 48 hours elapses between application of the foam and a
protective coating, the foam surface is to be inspected for contamination or oxidation. Should
either be present, the surface is to be brushed with a stiff broom or mechanically scoured and
reformed prior to application of the protective covering.
2.9
PERMEABLE FILTER MEMBRANE
2.9.1
General Requirements
1
Permeable filter membrane are to be chemically stable and made of rot resistant fabric,
manufactured from synthetic, thermally bonded, non woven fibre weighing not less than 140
g/m2 and minimum 0.7 mm thick. The membrane is to be capable of freely passing water
but preventing the passage of salt and clay particles.
2
Application and execution of workmanship must comply with procedures recommended by
the manufacturer.
3
Fabric must be applied around projections or areas of reinforcement in the widths and
thickness recommended by the manufacturer prior to final applications of the membrane.
2.10
PROTECTED MEMBRANE
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QCS 2014
Section 14: Roofing
Part
02: Membrane Roofing
Page 16
2.10.1
General Requirements
1
Protective membranes to membrane roofing shall be as specified in Part 4 of this Section.
2.11
TORCH APPLIED WATERPROOF MEMBRANE
2.11.1
General Requirements
1
Torch applied waterproofing membrane shall consist of a reinforced bitumen-polymer
membrane having the following minimum properties:
Thickness
3mm
Tensile Strength
BS 2782
7.5N/mm
Elongation
BS 2782
40%
Tear Resistance
ASTM D1004
100N
Moisture Vapour Permeability
BS 2782
8.5g/m /day
2
The waterproofing system shall incorporate the priming and reflective coating materials
recommended by the manufacturer of the membrane.
2
The waterproofing system shall be applied strictly in accordance with the instructions
supplied by the manufacturer.
TC
1
AM
END OF PART
QCS 2014
Section 14: Roofing
Part
03: Metal and Plastic Roofing
Page 1
3
METAL AND PLASTIC ROOFING ................................................................. 2
3.1
GENERAL ...................................................................................................... 2
3.1.1
3.1.2
Scope
References
3.2
FITTINGS AND ACCESSORIES ................................................................... 2
3.2.1
3.2.2
Fittings for Rigid Sheet Roofing
Fixing Accessories
3.3
ALUMINIUM SHEET FLASHING AND APRONS .......................................... 3
3.3.1
3.3.2
Materials Description
Installation of Aluminium Flashings and Aprons
3.4
CORRUGATED METAL SHEETS ................................................................. 3
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
Profiled Aluminium Sheets
Hop-Dip Zinc Coated Corrugated Steel Sheets
Installation of Corrugated and Troughed Roof Coverings
Fixing Profiled Aluminium Sheets
Fixing Galvanized Corrugated Sheets
3.5
CORRUGATED TRANSLUCENT SHEETS................................................... 6
3.5.1
3.5.2
3.5.3
Materials Description
Submittals
Fixing Corrugated Translucent Sheets
AM
TC
2
2
2
2
3
3
3
4
4
5
6
6
6
6
QCS 2014
Section 14: Roofing
Part
03: Metal and Plastic Roofing
Page 2
3
METAL AND PLASTIC ROOFING
3.1
GENERAL
3.1.1
Scope
1
This Part specifies requirements for use of metal and plastic roofing systems for buildings
and structures.
2
Related Sections are as follows:
Section 15
Section 18
Thermal Insulation of buildings
Carpentry, Joinery and Ironmongery
3.1.2
References
1
The following standards are referred to in this Part:
BS 1210 ......................Wood Screws
BS 1474 ......................Wrought aluminium and aluminium alloys for general engineering
purposes.
Bars, extruded round tube and sections
TC
BS 1494 ......................Fixing accessories for building purposes
BS 3083 ......................Hot-dip zinc coated and hot-dip aluminium/zinc coated corrugated
steel sheets for general purposes
AM
BS 3416 ......................Bitumen based coatings for cold application, suitable for use in contact
with potable water
BS 4154 ......................Corrugated plastic translucent sheets made from thermo-setting
polyester
resins (glass fibre reinforced)
BS 4868 ......................Profiled aluminium sheet for building
BS EN 485 ..................Aluminium and aluminium alloys - Plate, sheet and strip
3.2
FITTINGS AND ACCESSORIES
3.2.1
Fittings for Rigid Sheet Roofing
1
Fittings are to match the profile of the specified sheet and shall be supplied by the same
manufacturer.
3.2.2
Fixing Accessories
1
Screws for fixing aluminium roof edging, aprons, and the like are to be stainless steel to BS
1210, minimum 50 mm long.
2
Hook bolts and nuts shall comply with BS 1494, Part 1 and be 8 mm diameter cadmium or
zinc coated steel with plastic sleeves or applied plastic coating, shaped to suit the sheets and
roof members and complete with plastic washers.
QCS 2014
Section 14: Roofing
Part
03: Metal and Plastic Roofing
Page 3
Seam bolts and nuts for aluminium sheets are to be aluminium and to galvanized sheets to
be galvanized steel, 6 mm diameter and 40 mm long complete with plastic washers.
4
Filler pieces at ridges and eaves are to be approved pre-moulded cellular plastic or rubber
bitumen units to fit exactly the contours of the corrugations.
5
Sealant strip are to be approved flexible expanded polyurethane foam strip impregnated with
waxes and/or resins having an elastic recovery of 98% minimum and a density of not less
3
than 145 kg/m .
3.3
ALUMINIUM SHEET FLASHING AND APRONS
3.3.1
Materials Description
1
Aluminium sheet flashings, aprons, etc., are to be fabricated from 99.8 % aluminium sheet
and strip to BS EN 485, material designated 1080A, 0.9 mm thick.
2
Aluminium roof edging is to be fabricated form materials 6063-TB or 6063-TF complying with
BS 1474 to profiles to suit the verges and roof covering material.
3
Black bitumen coating solution shall comply with BS 3416, Type 1.
3.3.2
Installation of Aluminium Flashings and Aprons
1
Flashings, aprons, and the like, are to be formed from sheets not more than 1800 mm long
and to be lapped a minimum of 75 mm at intersections.
2
After folding and dressing, two coats of black bitumen coating solution are to be applied to all
areas, which will come into contact with materials containing cement. Repeated folding and
dressing should be avoided to prevent work hardening.
3
The top edge of flashings are to be provided with a 13 mm turn-back to act as a waterstop
and recessed a minimum of 25 mm into the wall. The flashing are to be fixed with 20 x 20
mm strips of aluminium folded into a wedge shape, covered with two coats of bitumen
solution and driven into the full depth of the recess at 400 mm centres. Upon completion of
fixing the recess are to be pointed in Class M6 cement mortar in accordance with Part 2 of
Section 13, Masonry.
4
Materials containing steel, copper, brass or bronze should not be allowed to come into
contact with aluminium.
3.4
CORRUGATED METAL SHEETS
3.4.1
Profiled Aluminium Sheets
1
Profiled aluminium sheets shall comply with BS 4868 and be manufactured from aluminium
alloy to BS EN 485, material designation 3103-H8, with a minimum tensile strength of
2
175 N/mm . Unless otherwise specified, Profile S, with a minimum thickness of 0.9 mm shall
be installed.
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QCS 2014
Section 14: Roofing
Part
03: Metal and Plastic Roofing
Page 4
Hop-Dip Zinc Coated Corrugated Steel Sheets
1
Hop-Dip zinc coated corrugated steel sheets shall comply with BS 3083 and shall have a
2
sheet thickness of 0.9 mm and minimum 450 g/m zinc coating.
3.4.3
Installation of Corrugated and Troughed Roof Coverings
1
The sheeting is to be laid with the open joint of side laps away from the prevailing wind. The
Contractor is to obtain the approval of the Engineer as to which end of the structure the laying
is to commence before beginning sheeting work.
2
The eaves course are to be laid first and subsequent sheets laid in tiers up to the roof from
eaves to ridge, aligning sheets on both slopes on double pitched roofs.
3
Corrugations or troughs are to be in line from eaves to ridge and eaves and verges are to
maintain proper alignment.
4
Sheets are to be cut to clean, true lines with no distortion. All burrs, drilling swarf or dust and
any other foreign matter to be removed before positioning sealing strips, filler pieces and
washers.
5
Openings for outlets, vent pipes, etc., are to be cut to the minimum size necessary. Vent
pipes and the like should always pass through the centre line of the crown and are to be
offset below roof level if necessary.
6
Holes through the sheets are to be drilled 2 mm larger than the diameter of the bolt and
always through the crown of the profile. No hole should be nearer than 40 mm to the end of
the sheet. All fixings are to be of the specified type and size and be in the correct position
true to line and secure.
7
Fittings are to be fixed, where possible, by the same bolts that secure the sheeting.
8
Filler pieces shall be installed between the corrugations or troughs and flat surfaces or
supports at the end of sheet runs wherever necessary to ensure airtightness of the structure.
9
A movement joint shall be provided in all lengths over 45 m. The joint is to be formed by
installing an approved proprietary movement joint cover in a suitably sized space between the
sheet.
AM
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3.4.2
QCS 2014
Section 14: Roofing
Part
03: Metal and Plastic Roofing
Page 5
3.4.4
Fixing Profiled Aluminium Sheets
1
Corrugated or troughened sheets are to be laid to comply with the requirements of with
Tables 3.1 and 3.2.
Table 3.1
Minimum Laps for Roof Sheeting
End Lap
Side Lap
mm
Corrugations
more than 15
150
1½
less than 15
230
1½
vertical
100
1
less than 15
150
1
more than 15
230
1
vertical
100
1
150
1½
230
1½
Material
Slope
Corrugated aluminium sheet
Troughed aluminium sheet
Corrugated Galvanized
2
more
than
15
Sheet
TC
less than 15
AM
Table 3.2
Maximum Permissible Dimensions for Roof Sheeting
Maximum Purlin
Spacing
(mm)
Maximum Rail
Spacing
(mm)
Maximum
Unsupported
Overhang
(mm)
Corrugated aluminium
1350
1500
150
Corrugated galvanized steel
2200
2400
350
Sheet Material
3
The centre line of end laps to coincide as nearly as possible with the centre line of supports,
or the back of angle purlins. All end laps to be fully supported.
4
Roofing sheets are to be fixed to metal purlins by hook bolts. Each bolt is to be fitted with a
metal washer shaped to the profile of the sheet and placed on the outer face together with a
plastic, or similar approved material, sealing washer, positioned between the metal washer
and sheet so that the bolt hole is sealed when the bolt is tightened. The bolt should be
tightened only sufficiently to seat the washer and so as to permit slight movement between
the structural frame and the sheeting.
5
Each sheet is to be fixed at every purlin or rail by at least two bolts situated at the side laps or
edges together with intermediate fastenings at maximum 375 mm centres.
6
In addition to purlin or rail fixings, side laps are to be secured by means of bolts or rivets
passing through the crown of the profile at the following maximum centres:
(a)
roofs more than 15 pitch
375 to 450 mm centres
(b)
roofs less than 15 pitch
300 to 375 mm centres
QCS 2014
(c)
Section 14: Roofing
Part
03: Metal and Plastic Roofing
vertical sheeting
Page 6
450 mm centres.
Ridge cappings are, where possible, to be secured to the roof by the same bolts that secure
the sheeting or, if the ridge purlin in not sufficiently near the ridge to permit this, the capping
should be secured to the sheeting on each side by seam bolts or rivets at maximum 450 mm
centres. The lap of the capping along the ridge should not be less than 150 mm with the open
joint away form the prevailing wind.
3.4.5
Fixing Galvanized Corrugated Sheets
1
Galvanised corrugated sheets are to be installed as described in Clause 3.4.3.
3.5
CORRUGATED TRANSLUCENT SHEETS
3.5.1
Materials Description
1
This Section covers pre-formed plastic panels or corrugated translucent sheets made from
thermosetting polyester resins to comply with BS 4154 and are to match the profile of the
adjoining metal sheets.
2
The colour of plastic panels shall be as designated in the Project Documentation unless
otherwise approved by the Engineer.
3.5.2
Submittals
1
Shop drawings for plastic panels shall show details of construction and installation, including
profiles, fastener types and flashing details.
2
Plastic panel samples, 750 mm square, shall be submitted for each colour or varying texture
finish used.
3.5.3
Fixing Corrugated Translucent Sheets
1
The sheets are to be laid with the same minimum side and end laps as the adjoining sheets.
Sealing strips be used where the end lap is less than 300 mm on roof pitches below 15.
2
Pre-moulded filler strips and clear mastic shall be used to seal laps.
3
Fixing accessories and holes are to be the same as used for the adjoining sheets.
4
Each sheet should be fixed at every purlin or rail by at least two bolts situated at the side laps
and three intermediate fastenings for use with galvanized or aluminium corrugated profiles.
5
In addition to purlin or rail fixings, side laps are to be secured by means of seam bolts at
maximum 300 mm centres. The use of self-tapping screws or blind rivets are not permitted.
6
Provide neoprene washers under bolt heads. If other fastenings are recommended by plastic
sheet manufacturer, install in accordance with manufacturer’s recommendations.
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END OF PART
QCS 2014
Section 14: Roofing
Part
04: Roof and Deck Insulation
Page 1
4
ROOF AND DECK INSULATION .................................................................. 2
4.1
GENERAL ...................................................................................................... 2
4.1.1
4.1.2
4.1.3
4.1.4
Scope
References
Submittals
General Application
4.2
RIGID BOARD INSULATION......................................................................... 3
4.2.1
General Requirements
4.3
PROTECTION OF INVERTED ROOF SYSTEMS ......................................... 3
4.3.1
General Requirements
4.4
POLYSTYRENE BOARD INSULATION ........................................................ 3
4.4.1
General Requirements
4.5
CEMENT-FIBRE ROOF DECK ...................................................................... 4
4.5.1
4.5.2
4.5.3
4.5.4
General Description
Cement-Fibre Roof Deck Planks
Accessories
Installations
4.6
INSULATING CONCRETE ROOF SCREEDS............................................... 5
4.6.1
4.6.2
4.6.3
General Description
Materials
Execution of Work
2
2
2
3
3
3
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4
4
4
5
5
5
6
QCS 2014
Section 14: Roofing
Part
04: Roof and Deck Insulation
4
ROOF AND DECK INSULATION
4.1
GENERAL
4.1.1
Scope
1
This Part specifies requirements for types of roofing and deck insulation.
2
Related Sections are as follows:
This Section
Part 1
Part 2
Part 3
Part 5
General
Membrane Roofing
Metal and Plastic Roofing
Roof tiles and Shingles
Section 1
Section 15
General
Thermal Insulation of Buildings
4.1.2
References
1
The following standards are referred to in this Part:
Page 2
TC
BS 3379 ......................Flexible polyurethane cellular materials for load bearing applications
BS 3797 ......................Lightweight aggregates for concrete
AM
BS 5075 ......................Concrete admixtures
BS 1105 ......................Wood wool cement slabs up to 125 mm thick
BS 3837 ......................Expanded polystyrene boards
BS EN 490 ..................Concrete roofing tiles and fittings - Product specifications
BS EN 491 ..................Concrete roofing tiles and fittings - Test methods
EN 197-1 ....................Portland Cement
4.1.3
Submittals
1
The contractor is to submit the following to the Engineer for approval before commencement
of work in this section.
2
Manufacturers literature and samples of roofing, thermal insulation, vapor barrier, roof
accessories, bitumen waterproof membranes, waterproofing materials, dampproof coursing
and elastometric sealants, etc.
3
Primary roofing materials inclusive of insulation, barriers or membranes should be obtained
from only one manufacturer if possible. Where secondary materials must be used, the
primary manufacturer is to be provided with adequate literature and samples for concurrence
that the secondary products are compatible for roofing warrantees. Concurrence will be
provided by the Contractor in writing to the Engineer prior to commencement of work.
QCS 2014
Section 14: Roofing
Part
04: Roof and Deck Insulation
Page 3
General Application
1
Expanded extruded polystyrene boards shall comply with BS 3837, Grade EHD, Type A,
extruded board with skins.
2
Spray applied polyurethane or isocyanurate foam insulation is to be protected from
deterioration due to ultra violet light by a covering approved by the manufacturer of the foam.
3
Where spray applied foam is used as an integral part of the roof waterproofing system it must
be specifically included in the manufacturer’s guarantee requirements.
4
Unless otherwise specified the insulation is to be at least equivalent to 50 mm thick material
having an ultimate thermal conductivity of 0.032 W/mK at a mean temperature of 10C and a
compressive resistance of not less than 150 kN/m2.
4.2
RIGID BOARD INSULATION
4.2.1
General Requirements
1
Rigid insulation boards are to be installed as a single layer to the thickness specified.
2
All joints between rigid insulation boards are to be tight and no gaps should exist where the
board meets rooflights, edge details and services penetrating the roof structure. End joints
are to be staggered.
3
On corrugated surfaces all long edges are to be supported by the crown of the corrugations.
4.3
PROTECTION OF INVERTED ROOF SYSTEMS
4.3.1
General Requirements
1
Insulating material having a water absorption in excess of 1.5% by volume in seven (7) days
at 20 ºC are not to be used in inverted roof systems.
2
The insulation is to be covered by a layer of permeable filter membrane, laid loose and
lapped 200 mm at all intersections before the paving slabs or solar reflective chipping is laid.
3
Paving slab protection is to be loose laid with 6 mm open joints on 100 x 100 x 6 mm
inorganic spacers positioned at the corner junctions of the slabs. The paving slabs will have
a minimum thickness of 40 mm on insulation boards of up to 50 mm and for every 10 mm
increase in the insulation thickness the slab thickness should be increased by 5 mm.
4
Aggregate protection is to consist of a 50 mm minimum layer of chippings on insulation
boards of up to 50 mm. The thickness of the aggregate layer to be increased to a depth
equal to the thickness of insulation boards over 50 mm.
4.4
POLYSTYRENE BOARD INSULATION
4.4.1
General Requirements
1
Polystyrene board insulation shall conform to BS 3837, and shall include the following
requirements:
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4.1.4
QCS 2014
water absorption shall not be more than 0.1 % by weight
(b)
density shall not be less than 32 kg/m for Type VI
3
Standard polystyrene boards shall conform to the following requirements:
(a)
nominal size shall be approximately 600 by 1200 mm minimum
(b)
they shall have a drainage channel on the bottom longitudinal edge of the board
(c)
they are to have a flat top surface where gravel ballast in used or ribbed bottom pavers
are used
(d)
they are to have ribbed top surface where flat bottom paver is used
(e)
they are to be tapered for roof slope where top surface is level
(f)
the edges shall be square, except for drainage channels.
Mortar faced boards shall conform to the following requirements:
(a)
(a)
boards shall be top surfaced with 10 mm thick facing of Portland cement latex
mortar having the following physical properties:
1240 kg/m
3
(i)
density
(ii)
compressive strength (28 days)
(iii)
bond strength to insulation1 MPa
(iv)
troweled finish with texture
25 MPa
TC
3
(a)
Page 4
(b)
drainage channels on bottom longitudinal edges of board
(c)
nominal size shall be approximately 600 by 1200 mm minimum
(d)
they shall have tongue and grooved longitudinal edges
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Section 14: Roofing
Part
04: Roof and Deck Insulation
4.5
CEMENT-FIBRE ROOF DECK
4.5.1
General Description
1
This Clause covers the furnishing and installation of cement-fibre roof deck planks.
4.5.2
Cement-Fibre Roof Deck Planks
1
Cement-Fibre planks shall be manufactured from treated wood fibres and Portland cement,
bonded under pressure to BS 1105. The length and width of planks to be shown on plans will
comply with manufacturer’s requirements to suit span and load. The long edges are to be
tongue and grooved and the ends square. Zinc coated steel channels will be factory applied
in the groove of the plank. A factory bonded layer of urethane foam insulation shall be applied
to the top of the plank.
2
Examine planks before installation. Broken or cracked planks should not be used.
Where exposed, repaint soiled planks with paint recommended by the plank manufacturer to
match colour and texture of adjacent planks.
4.5.3
Accessories
1
Clips shall be as recommended by the cement-fiber plank manufacturer to suit the supporting
members.
QCS 2014
Section 14: Roofing
Part
04: Roof and Deck Insulation
Page 5
Nails shall be galvanized cork type with integral 25 mm washer, of length to penetrate wood
support not less than 25 mm.
4.5.4
Installations
1
Planks shall be cut to fit tight at perimeters, vertical surfaces, projections and openings. All
edges and ends of planks and perimeter of openings greater than 200 mm are to be
supported by framing members and bearing walls.
2
Planks are to be laid progressively with side joints (edges) tightly butted and with end joints in
adjacent rows staggered.
3
Clips or nails are to be installed progressively as each plank is installed. Clips or nails are to
be installed in accordance with the manufacturer's instructions.
4
Install a barrier, full depth of the plank, over the top of sound rated partitions and at the
perimeter of exterior walls.
4.6
INSULATING CONCRETE ROOF SCREEDS
4.6.1
General Description
1
This section covers insulating concrete placed on a prepared structural deck.
2
Insulating concrete placed on steel deck forms are to have underside venting through
slotted holes formed in the metal deck, combined with edge venting or topside venting
through roof relief vents.
3
Insulating concrete placed over cast-in-place concrete or precast concrete substrates, is to
be vented through the use of topside roof relief vents combined with edge venting.
4.6.2
Materials
1
Refer to Section 5, Concrete, for specifications relating to sand, cement, aggregates and
water.
2
Portland cement shall conform to EN 197-1.
3
Concrete roofing tiles shall conform to BS EN 490 and BS EN 491.
4
Light weight aggregates shall conform to BS 3797.
5
Chipping shall be approved, clean, crushed white or pale grey, size 15 to 30 mm and shall
comply with BS 3379.
6
Air entraining agent refer to BS 5075 Prt 2 and shall be a type as recommended by
aggregate suppliers. Admixtures with chloride salts or pre-generated foam types are not
acceptable.
7
Permeable filter membrane shall be to Clause 2.9.1.
8
Control joint filler shall be glass fibre or similar highly compressible material, which will
compress to half of its thickness under a load of 170 KPa or less.
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QCS 2014
Section 14: Roofing
Part
04: Roof and Deck Insulation
Page 6
Wire mesh reinforcing shall be used when roof deck slopes exceed 1:3 and for fire rated roof
assemblies using metal decking. The wire mesh shall be 1 mm galvanized steel wire twisted
to form 50 mm hexagons with 1.6 mm galvanised steel wire woven into mesh spaced 200
mm apart. Welded wire fabric of equivalent size may also be used an approval of the
Engineer.
4.6.3
Execution of Work
1
The surface of the concrete base must be clean, firm and rough to ensure a good bond.
2
The base should be soaked with water for at least 12 hours and all surplus water removed
before laying commences.
3
To obtain the required falls and thickness of screed, leveling battens are to be used, carefully
fixed to line and level and fully bedded. There should be a minimum thickness of 40 mm of
screed over the top of any conduit or duct.
4
Immediately prior to laying the screed, a thick brush coat of wet cement grout should be
applied to the damp surface of the base concrete and be well scrubbed in. The brush coat
must not be applied more than 10 minutes before it is covered with screed. Alternatively, the
Engineer may required that surfaces which have been left for an excessive period of time
before the screed is laid be treated with an approved bonding agent.
5
The screed is to consist of 1 part of cement to 5 parts of sand by weight. The mix shall only
contain sufficient water that will allow full compaction and be evenly spread to a thickness
approximately 10 mm greater than that required. The screed is to be thoroughly compacted
by tamping and drawing off to the required level with a screed board.
6
The screed is to be laid in alternated bays, maximum 10 m², with plain butt joints to provide
minimum falls of 1:80 and a minimum thickness of 50 mm. Movement and construction joints
in the base should be carried through the screed.
7
The joints between bays and at junctions with all upstands are to be minimum 12 mm wide
and be filled for the full depth of the joint with sealing strip or an approved polysulphide joint
filler and sealing compounds.
8
A 75 x 75 mm triangular fillet is to be provided at the junction with all upstands.
9
The top surface is to be floated to smooth and even falls suitable for the waterproofing
system to be employed and be free of low areas, lumps and projections. Care should be
taken to avoid excessive trowelling which may cause crazing.
10
As soon as each bay is completed and has hardened sufficiently to prevent damage to its
surface, it should be covered with polythene or similar sheets which should be adequately
lapped and held down. The screed must not be allowed to dry out for a minimum period of
seven (7) days and no traffic should be permitted on the surface during this time.
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END OF PART
QCS 2014
Section 14: Roofing
Part
05: Roofing Tiles and Shingles
Page 1
5
ROOFING TILES AND SHINGLES ............................................................... 2
5.1
GENERAL ...................................................................................................... 2
5.1.1
5.1.2
Scope
References
5.2
CLAY SHALE AND CONCRETE ROOFING TILES ...................................... 3
5.2.1
5.2.2
5.2.3
General
Products
Execution of Installation
5.3
ROOFING SHINGLES ................................................................................... 4
5.3.1
5.3.2
5.3.3
General
Metal, asbestos-cement and Asphalt Shingles
Shakes and Shingles of Other Materials
2
2
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3
3
4
4
4
QCS 2014
Section 14: Roofing
Part
05: Roofing Tiles and Shingles
Page 2
5
ROOFING TILES AND SHINGLES
5.1
GENERAL
5.1.1
Scope
1
This Part specifies requirements for and the installation of roof tiles made of clay, shale and
concrete, and additionally for shakes or shingles made of other materials.
2
Related Sections are as follows:
General
Membrane Roofing
Metal and Plastic Roofing
Roof and Deck Insulation
Section 1
Section 5
Section 13
Section 14
Section 15
Section 17
Section 18
Section 24
General
Concrete
Masonry
Roofing
Thermal Insulation of Buildings
Metalwork
Carpentry, Joinery and Ironmongery
Finishes to Buildings
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This Section
Part 1
Part 2
Part 3
Part 4
3
In general, roofing tile and shingle materials and their application shall conform to BS 5534,
BS 8000 Part 6, BS EN 490, BS EN 491 and BS EN 539.
5.1.2
References
1
The following standards are referred to in this Section:
BS 402 ........................Clay plain roofing tiles and fittings
BS 680 ........................Roofing slates
BS 747 ........................Roofing felts
BS 1202 ......................Nails
BS 1521 ......................Waterproof building papers
BS 4016 ......................Building papers (breather type)
BS 5534 ......................Code of Practice for slating and tiling
BS 8000 ......................Workmanship on building sites
BS EN 490 ..................Concrete roofing tiles and fittings - Product specifications
BS EN 491 ..................Concrete roofing tiles and fittings - Test methods
BS EN 538 ..................Clay roofing tiles for discontinuous laying flexural strength test
BS EN 539 ..................Clay roofing tiles for discontinuous laying - determination of physical
characteristics
QCS 2014
Section 14: Roofing
Part
05: Roofing Tiles and Shingles
Page 3
5.2
CLAY SHALE AND CONCRETE ROOFING TILES
5.2.1
General
1
Roofing tiles made of clay, shale and concrete roofing tiles shall comply with (but are not
limited to) the respective standards as follows:
3
clay, shale roofing tiles: BS 402, BS 680, BS EN 538, BS EN 539, and BS 8000 Part 6
(b)
concrete roofing tiles: BS 680, BS EN 490 and 491, and BS 8000 Part 6.
Submittals of roofing materials to be used will be made by the Contractor in accordance with
the relevant provisions of Section 1, General, shall include furnishing of the following:
(a)
samples of each colour of each type of tile required in the Works; the tiles shall be of
finished product quality and shape
(b)
shop drawings with details of any fabricated custom shapes and installation
requirements.
Product Delivery, Storage and Handling:
(a)
tiles and setting materials shall be delivered in manufacturers’ original, unopened
containers clearly identifying manufacture and the contents
(b)
tiles shall not be stored in the flat position.
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2
(a)
The Contractor shall guarantee materials and workmanship to be free from defects and leaks
for a period of two (2) years.
5.2.2
Products
1
Clay and shale roofing tiles shall be English, French, Greek, Roman or Spanish type unless
otherwise specified in the Project Documentation or approved by the Engineer, and all tiles
are to be hard burned, dense, fully vitrified, clay or shale, free from fire cracks or defects.
2
Concrete roof tiles will be of quality materials to BS EN 490 and BS EN 491.
3
Non-interlocking locking or interlocking tiles are acceptable, but should not be intermixed in
use.
4
Nails brads, staples and spikes and any other fasteners used to secure tiles shall be
corrosion-resistant nails or wire to BS 1202.
5
Felt underlay should be to tile manufacturer’s recommendations for related roof slope. Felt
underlay shall be asphalt saturated organic felt, without perforations, nominal 66 kg/m2 to BS
747 unless otherwise shown on the drawings and shall comply to BS 4016, BS 1521 and
BS 747.
5.2.3
Execution of Installation
1
Vent pipes and other projections through roofs and flashing materials are to be in place
before laying tiles.
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QCS 2014
Section 14: Roofing
Part
05: Roofing Tiles and Shingles
Page 4
2
Felt underlay shall be laid in single thickness, parallel to eaves with double thickness at hips
and ridges. Horizontal joints shall be lapped 75 mm and vertical joints lapped 150 mm.
Vertical joints shall be staggered. Felt shall be extended up 150 mm at abutting vertical walls,
chimneys and parapets. Under the edges of built-up gutters, valleys, and metal flashings, the
felt shall be lapped not less than 100mm.
3
Laying Tile
(a)
tiles shall be laid free of horizontal obstructions which would impede shedding of
surface water
(b)
courses shall be laid parallel with eaves
(c)
each tile shall be secured by at least two nails, of copper or stainless steel wire and
shall be fastened where practicable
(d)
nails and wire fastenings in finished work shall be covered
(e)
tiles shall be laid with an end lap of at least 75 mm
(f)
fill laps of end bands, of tiles on ridges, and gable rakes with roofers plastic cement
(g)
roofers plastic cement may be used for levelling tiles and for pointing around eave
bridge closures.
Upon completion of the tiling, any cement splatter shall be removed from tile and adjacent
surfaces.
5.3
ROOFING SHINGLES
5.3.1
General
1
Roofing shingles, as specified in this Section, are inclusive of all non-clay, shale or concrete
tiles which are used in the same manner as roofing elements used in an overlapping system
on sloped roofs.
5.3.2
Metal, asbestos-cement and Asphalt Shingles
1
Metal, asbestos-cement and asphalt shingles shall be installed in an approved manner as
established by acceptable proprietary manufacturers and as detailed in the drawings
5.3.3
Shakes and Shingles of Other Materials
1
Other shake or shingle products of man-made plastic or compounds will require
submittal of product specification and samples for testing prior to approval. Such products
shall be installed in an approved manner as established by acceptable proprietary
manufacturers and as detailed in the drawings.
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END OF PART