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Taking on this sort of task can be daunting, but thoroughly rewarding. This is a brief guide on repairing and replacing your shed or garage roof. Recommended bicycle store, shed or garage roof materials: Bitumenised corrugated sheets and roofing ridge pieces plus 70 mm PVC headed fixing nails. Corrugated bitumenised sheets are supplied in black or green colours to blend into your garden (shed structure), or look ideal on your property's adjacent garage. Wooden purlins size 40mm x 40mm (or similar size) depending on the roof area size. Take advice from your Builders' or Timber Merchants' trade counter and use what size the trade recommend. Large chipboard or plywood sheets may be needed to support the purlins in your shed or garage roof decking structure. You may also need large timber joists stretched across your single slope, garage roof area, if that is the building plan design you are working with. Material sizes: Bitumenised corrugated sheets @ 2 metres x 950mm wide. Bitumenised roof ridge pieces @ 900mm x 500mm wide. Corrugated roof sheets must be laid with the tighter weave on the exterior roof surface and the larger dimples on the underside to assist with ventilation. Power tools: Power tools often make light work of even the toughest job. Cutting down on the time it takes to complete a job and making your life easier. For this job we recommend the following power tools: Circular power saw for cutting to size all bitumenised roof sheets, ridge pieces, wooden purlins and roof joists, or decking plywood or chipboard; hammer; power drill, driver and drill bits for fixing into place all plywood or chipboard decking and purlins. Nail fixing: Your bitumenised corrugated roof sheets are fixed to the purlins placed at 600mm centres on roof pitches of 15 degrees and over, using special 70mm PVC headed roofing nails. Simply hammer them into position and use a tight draw string to follow your nail positioning across the roof and along each of the purlin centres. With roof pitches less the 15 degrees, (e.g. 10 and upto 15 degrees), purlins should then be positioned at 450mm centres to provide added strength. Why use bitumenised corrugated sheets? They are very lightweight, robust and easy to handle. Each sheet is quickly fixed to a roof structure using PVC headed nails. The perfect answer for a new or replacement roof for a garden or cycle shed, or garage roof. Both chemical and corrosion resistant. Asbestos free material. Thank goodness. Easy to cut and fix to both garden sheds or a garage roof. Being flexible, they can even be fixed to a slightly uneven roof area as they will bend to accommodate any such variations in the structure. Waterproof and water-tight once nailed into position. They are exceptionally cheap and good value for both DIY enthusiasts wanting to save money, plus tradesmen wanting to stay competitive in the home-owner and business sector marketplaces. Safety Covering a roof with corrugated sheets is a two man job (preferably) and you must take every precaution when working. Be sure ladders are fixed rigidly at the top and tied to the building's sturdy wooden frames. Place a sandbag stopper support at the rear of the ladder's feet to prevent it from sliding when mounted by a worker. When working on this type of lightweight roof covering, always use a roof board to spread your weight across multiple roofing purlins and supports. Be sure it has a thick soft cushioning material beneath to avoid any cracking or splitting of the corrugated sheets and crowns. Never handle roof building or replacement projects using large, bitumenised, corrugated sheets in any high winds as the sheets act like sails in these difficult conditions. It is very dangerous and should not be undertaken even when the wind is only a slight breeze. Corrugate sheets must be positioned upright to run from the highest to the lowest point and at right angles to each purlin. Never place a corrugated sheet in the horizontal plane across a shed or garage roof structure - It will not function correctly, or dispose of any rainwater easily. TIPS Do not drill and fix a bitumenised corrugated sheet in the valley of the sheet's corrugated design - It will invariably leak when it rains. Nail through the top (crown) of each convex curved corrugated ripple using a wooden support beneath the crown when you commence nailing. Do not cut corrugated sheets in the extreme cold - they will split or shatter. If you are erecting a roof cover on a shallow garage roof pitch, be sure it is strong enough to be able to withstand a heavy snowfall in winter. Place and space purlins at 450mm centres. Fix all roof sheets loosely at first and, when happy with their positioning, overlaps and verge overhangs, tighten the fixings but don't over-tighten them. Corrugated, bitumenised roof sheets do not need holes drilling at first. The nails are driven straight through each bitumenised sheet's corrugated crown and each hole is sealed by the nail's PVC head cover. Roof pitches 10 to 15 Degrees All roof support purlins must be positioned at 450 mm centres (or closer) for added strength. Side overlaps of roofing sheets must be 1 full corrugation. Use two corrugations on shallow roof pitches of less than 10 degrees. End overlaps of two roof sheets must be at least 200mm. Use 260mm overlaps on shallow roof pitches of less than 10 degrees. Overlap roof ridge pieces by a minimum of 110mm as you nail each piece to the roof apex purlins and corrugated sheeting already in position beneath. When draining corrugated roof sheets into a rainwater gutter facility, allow at least a 65mm roofing overhang. Do not extend beyond 70mm as strong winds could easily catch under the roof and cause untold damage very quickly. In buildings where there is the possibility of high humidity (eg. with animals inside plus a concrete floor base), I strongly recommend you put a vapour barrier of bitumen felt beneath the purlins during construction. Make sure it is taut by stapling it tight. Overlaps must be a minimum of 120mm. Do not put in bitumen felt where livestock can reach and chew it. Alternatively, cut and fix exterior ply beneath the purlins to prevent any condensation penetration. Cut and place a barge board verge beneath the corrugated roof sheets at each side of the roof where it has a deliberate corrugated overhang. Start the sheet fixing by nailing through the corrugated crowns into the purlins at the edge of the roof and then fold down the corrugation edge onto the barge board along the roof overhang and nail down into position - it will make a perfect finish. Nail down every crown at the bottom edge of each corrugated sheet leaving a maximum overhang of 70mm for the rainwater gutter. At each other purlin you only need nail through every other crown point, except also along the roof apex purlin, where you must nail down through each crown point. Be sure to use a taut string nailing guide along every purlin, especially along the roof apex. Roof pitches 15 degrees and over All roof support purlins should be at 600mm centres. Side overlaps of each roofing sheet must be 1 full corrugation. End overlaps of two roof sheets must be at least 180mm. When draining corrugated sheeting into a rainwater gutter facility, allow the same maximum 70mm roofing overhang as already stated. Side roof overhangs must be must at least one full corrugation and carefully positioned so that rainwater does not run down the side of a shed, garage, building, canopy or carport. It must be no more than 70mm in its roofing extension. NOTE You may find some buildings require Planning Consent and structural build programmes that conform to certain new Build Regulations. Be sure to check with the appropriate building professionals first, before going ahead with your roofing construction plans. Bitumenised corrugated roofing sheets and clear PVCu roofing sheets offer enormous building savings' potential for DIY enthusiasts, farmers, zoo owners, builders, landscape gardeners, allotment owners, market gardeners, plant breeders, and business trying to erect new storage areas and reduce building capital costs, wherever possible. Be sure to think how you can build cheaper, by erecting an economical, corrugated, sheet roofing system that will dramatically reduce capital outlay costs and yet still deliver on sturdiness, durability and waterproofing. Cut down the hassle of this sort of job by making the most of the power tools available to you. Power tools often make light work of even the toughest job. Cutting down on the time it takes to complete a job and making your life easier.
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