Woodside General Learning Areas (6) 0421 ROOFING – COMBINED

0421 ROOFING – COMBINED

1 GENERAL

1.1 AIMS

ResponsibilitiesProvide a roofing system and associated work which:

- Remains intact and waterproof under the local or regional ambient climatic conditions.

- Protects people, property and the environment from the adverse effects of stormwater.

- Provides adequate means of dealing with vapour pressure, condensation, corrosion and thermal movement.

- Satisfies other specified performance requirements.

1.2 CROSS REFERENCES

GeneralGeneral: Conform to the General requirements worksection.

Associated worksectionsAll sections of this specification are to be referred to as one document

1.3 PERFORMANCE CRITERIA

Ambient climatic conditionsDesign rainfall intensity (mm/h) to AS/NZS 3500.3: 123mm for eaves gutters

2 PRODUCTS

2.1 COMPONENTS

FastenersSelf-drilling screws: Corrosion resistance Class 3.

Finish: Prefinish exposed fasteners with an oven baked polymer coating to match the roofing material.

Fastenings to timber battens: Provide fastenings just long enough to penetrate the thickness of the batten without piercing the underside.

Profiled fillers Provide: Purpose-made closed cell polyethylene foam profiled to match the roofing profile.

Locate profiled fillers under flashings to:

- Ridges.

- Eaves.

- Lapped joints in roof sheeting.

2.2 SHEET METAL ROOFING

GeneralType: Provide a proprietary system of preformed sheet and purpose-made accessories.

Prepainted and organic film/metal laminate products: To AS/NZS 2728.

Product type 1: Lysaght Custom Orb or equal approved

Design and installation: To AS 1562.1. and HB 39

Material: Zincalume steel conforming to AS 1397-G550-AZ150

Thickness (base metal) (mm): 0.48 BMT

Product finish: Zincalume

Fixing: To Manufacturer’s details

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Accessories: Provide material with the same finish as roofing sheets

Product type 2: Lysaght Spandek or equal approved

Design and installation: To AS 1562.1. and HB 39

Material: Zincalume steel conforming to AS 1397-G550-AZ15

Thickness (base metal) (mm): 0.48 BMT

Product finish: Zincalume

Fixing: To Manufacturer’s details

Accessories: Provide material with the same finish as roofing sheets

2.3 ROOF PLUMBING

GeneralStandard: To AS/NZS 3500.3.

General: Provide the flashings, cappings, gutters, rainwater heads, outlets and downpipes necessary to complete the roof system.

MaterialsMetal rainwater goods: To AS/NZS 2179.1.

Flashings and cappingsFlashing material: To AS/NZS 2904.

Type: Colorbond or Zincalume as noted on drawings – NOTE: No ‘Dektite’ flashings to be used. Refer flashings and cappings below

2.4 RAINWATER TANKS

GeneralAccessories: Provide the accessories needed to complete the installation, including inlet and outlet connections, and flywire screened overflow and access hole.

Outlets: Double fitted so that fitting is rigid.

- Tanks  6600 L: 20 mm minimum.

- Tanks > 6600 L: 25 mm minimum.

Access hole: Cut access hole above the highwater level, and cover with either a strainer or a top fixed securely to the tank. Provide soluble chemical protector units.

Relocate existing

Coated steel tanksProvide one off new steel tank.

Product: Colorbond

Location: refer Drawings

Capacity: 5000L

Roof:

- Conical.

- Flat and back propped internally with a tightly fitting length of PVC downpipe.

Support: Fully support the tank above ground level.

Material: Metallic-coated steel.

Rivetted and capped joints:

- Base: Either 6 mm grooved seams for tanks  2.1 m diameter, or riveted seams for tanks of any size. Space rivets at 50 mm maximum centres, and overlap sheets 25  3 mm.

- Walls: For corrugated sheet, rivet at every corrugation and end-lap 100 mm minimum.

- Girth seams: Space rivets at 300 mm maximum centres. Provide either 4.8 mm (minimum) blind rivets or No. 8 (minimum) solid rivets.

Overflow: Area at least the total tank inlet area.

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Coated steel tanks material table

Component Minimum base metal thickness (mm)

Grade to AS 1445

Coating class to AS 1397

Profile/Pitch x no. of corrugations 3 m

diameter or  17 000 L

> 3 m diameter or > 17 000 L

Base 0.6 0.8 G 300 Z 275 or AZ 150

Flat

Walls 0.6 0.8 G 250 Z 600 76 x 8

AZ 200 76 x 10.5

Top 0.6 0.6 G 300 Z 275 Flat

AZ 150 Conical

3 EXECUTION

3.1 INSTALLATION

ProtectionGeneral: Keep the roofing and rainwater system free of debris and loose material during construction, and leave them clean and unobstructed on completion. Repair damage to the roofing and rainwater system.

Touch up: If it is necessary to touch up minor damage to prepainted metal roofing, do not overspray onto undamaged surfaces.

Thermal movementProvide for thermal movement in the roof installation and the structure, including movement in joints and fastenings.

Pan type sheetsRemoval: Capable of being de-indexed and removed without damage.

Curved corrugated sheetGeneral: Form by rolling from material recommended for curving or bullnosing. Minimise crimping or creasing across the face of the sheet. Trim off crimped or creased edges and ends.

Metal separationPrevent direct contact between incompatible metals, and between green hardwood or chemically treated timber and aluminium or coated steel, by either:

- Applying an anti-corrosion, low moisture transmission coating to contact surfaces.

- Inserting a separation layer.

TolerancesConform to the Tolerances table.

Tolerances table

Property Tolerance criteria: Permitted deviation (mm)

Spacing of supporting members ± 5 mm on the nominated support member spacing

Vertical or horizontal misalignment at the abutting ends of sheets

≤ 2 mm

Tops of supporting members in a plane parallel to the nominated roof slope

≤ 7 mm smooth deviation per metre length of supporting member

3.2 SAFETY MESH

StandardGeneral: To AS/NZS 4389.

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3.3 SHEET METAL ROOFING

Roof sheet installationAccessories: Provide material with the same finish as roofing sheets.

Expansion joints: Refer to drawings

3.4 BUILDING ELEMENTS

Ridges and eavesTreat ends of sheets as follows:

- Project sheets 50 mm into gutters.

- Close off ribs at bottom of sheets using mechanical means or with purpose-made fillers or end caps for birdproofing.

- Turn pans of sheets up at tops and down into gutters by mechanical means.

- Provide pre-cut notched eaves flashing and birdproofing where necessary.

- Close off ridges with purpose-made ridge fillers of closed cell polyethylene.

Ridge and barge cappingFinish off along ridge and verge lines with purpose-made ridge capping or barge rolls.

Sprung curved ridgeLay the roof in single lengths from eaves to eaves by naturally curving the sheets over the ridge.

End lapsGeneral: Where end laps are unavoidable, and the sheet profile is not suitable for interlocking or contact end laps, construct a stepped type lap.

3.5 ROOF PLUMBING

Jointing sheet metal rainwater goodsButt joints: Make joints over a backing strip of the same material.

Soldered joints: Do not solder aluminium or aluminium/zinc-coated steel.

Sealing: Seal fasteners and mechanically fastened joints. Fill the holes of blind rivets with silicone sealant.

Flashings and cappingsFlashing material: To AS/NZS 2904.

Type: Colorbond or Zincalume as noted on drawings No ‘Decktite’ flashings to be used

Installation: Flash roof junctions, upstands, abutments and projections through the roof. Preform to required shapes where possible. Notch, scribe, flute and dress down as necessary to follow the profile of adjacent surfaces. Mitre angles and lap joints 150 mm in running lengths. Provide matching expansion joints at 6 m maximum intervals.

Upstands: Flash projections above or through the roof with two part flashings, consisting of a base flashing and a cover flashing, with at least 100 mm vertical overlap. Provide for independent movement between the roof and the projection.

Wall abutments: Provide overflashings where roofs abut walls, stepped to the roof slope in masonry and planked cladding, otherwise raking.

- In masonry: Build into the full width of the outer leaf. Turn up within cavity, sloping inward across the cavity and fixed to or built in to the inner leaf at least 75 mm above.

- In concrete: Turn 25 mm into joints or grooves, wedge at 200 mm centres with compatible material and point up.

Fixing to masonry or concrete: Step in courses to the roof slope. Interleave with damp proof course, if any.

Fixing to pipes: Solder, or seal with neutral cured silicone rubber and either of the following:

- Secure with a clamping ring.

- Provide a proprietary flexible clamping shoe with attached metal surround flashing.

GuttersGeneral: Prefabricate box gutters. Form stop ends, downpipe nozzles, bends and returns. Dress downpipe nozzles into outlets. Provide overflows to prevent back-flooding.

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Gutter and sump support: Provide framing and lining to support valley gutters, box gutters and sumps. Line the whole area under the gutters and sumps.

Support: For standard eaves gutter:

30mm x 1mm galvanised ms straps and saddles, coating class Z275, at not more than 1000mm centres, bent and screw fixed to purlins or built into brickwork.

Valley gutters: Profile to suit the valley boarding. Turn back both edges 180 x 6 mm radius. Nail or screw to the valley boarding at the top end to prevent the gutter creeping downwards.

Guards: Provide leaf guards to gutters: Fielders ‘Watergate’ to all new gutters

Ball guards to gutter outlets: Ball guards are to be fabricated by the roofer from two pieces of 10-15mm flat iron pop riveted together at 90o to each other. These are to be bent into a dome and placed inside the pops in the sumps and gutters. Bird mesh wire ball guards are not acceptable.

Gratings: Provide removable gratings over rainwater heads and sumps:

Expansion joints: Provide expansion joints in guttering longer than 30 m:

Matching fascia/barge: Where the selected eaves gutter is a proprietary high front pattern forming part of a combined system of gutter, fascia and barge, provide the matching proprietary fascias and barge cappings to roof verges and edges.

DownpipesGeneral: Prefabricate downpipes to the required section and shape where possible. Connect heads to gutter outlets and, if applicable, connect feet to rainwater drains.

Access cover: Provide a removable watertight access cover at the foot of each downpipe stack.

Downpipe support: Provide supports and fixings for downpipes.

Sound insulation: Mineral fibre pipe insulation 50 mm thick, spirally bound on with 1.5 mm wire at 150 mm pitch.

Building in: Where pipes are built into masonry or concrete, spiral wrap the pipe (and insulation, if any) with building paper.

Gutter and downpipe schedule

Item Material, grade and finish

Shape and size and thickness

Jointing method Colour

Valley gutter Zincalume steel As indicated on drawings

Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Eaves gutter Zincalume steel Lysaght D gutter or similar approved

Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Box gutter Zincalume steel Refer to drawings Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Rainwater heads and sumps

Zincalume steel Refer to drawings Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Downpipe Zincalume steel 1.0mm all lengths Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Overflows Zincalume steel 0.6mm Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

Overflow spouts Zincalume steel 0.6mm Lapped rivetted and sealed

Refer to FINISHES SCHEDULE

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Rainwater disposalRefer to Plan

3.6 PLASTIC SHEET ROOFING

InstallationStandard: To AS/NZS 1562.3.

Fixing: to Manufacturer’s details

3.7 ROOF VENTILATORS

InstallationFixing: To Manufacturer’s details

3.8 COMPLETION

WarrantiesSubmit the roofing materials manufacturer’s published product warranties.

Spare Materials

Number: Provide one spare matching downpipe for every full height new downpipe and rain head.

Location: Hand over to the Proprietor

Maintenance manualOn completion submit a manual of recommendations from the roof manufacturer or supplier for the maintenance of the roofing system including, frequency of inspection and recommended methods of access, inspection, cleaning, repair and replacement.

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