Specialty Roofing: Cedar, Sheds, Roll Roofing, Patio Covers and Synthetics
6 step by step guides
Not every roof is a standard asphalt shingle roof on a house. The Fraser Valley has a lot of older cedar shake roofs, backyard sheds, garages and workshops with low slopes, patio covers that need light as well as shelter, and newer composite products that imitate slate and shake. Each has its own rules for slope, fastening and movement.
Cedar is the most demanding. A shake roof sheds water through spaced, overlapping wood with keyways between the pieces, so the details in how to install cedar shakes are quite different from shingles, and replacing a single cedar shake is a careful job of slipping wood under its neighbours. For small outbuildings, see how to roof a shed and how to install roll roofing.
Patio covers and synthetic products fail for different reasons: a polycarbonate sheet that is fastened too tightly cracks with the first hot afternoon, and a synthetic slate fastened the wrong way voids its own instructions. For those, go to polycarbonate patio roofs and synthetic slate and shake. In every case, the manufacturer's instructions govern.
Specialty Roofing Guides
- Guide 1How to Replace a Cedar ShakeTo replace a cedar shake, split the damaged shake into pieces with a chisel and remove them, cut the hidden nails with a shake ripper (slate ripper), trim a new shake about 3/4 inch narrower than the opening so it leaves a keyway of about 3/8 inch on each side, slide it up to the correct exposure, and fasten it with two galvanized or stainless nails driven where the course above covers them, or sealed if exposed. Only work dry, with fall protection.Advanced30 to 60 minutes per shake
- Guide 2How to Install Cedar ShakesCedar shakes go on spaced or solid sheathing with a doubled starter course, 18 inch wide strips of 30 pound interlay felt laid between courses, keyways of about 3/8 inch between shakes offset at least 1-1/2 inches from the course below, and two corrosion-resistant nails per shake about 3/4 inch from the edges and 1-1/2 inches above the exposure line. Common maximum exposures are 7-1/2 inches for 18 inch shakes and 10 inches for 24 inch shakes.Professional2 to 5 days for an average roof
- Guide 3How to Roof a ShedTo roof a shed, check the deck is solid, pick a covering that suits the slope (asphalt shingles from about 4/12, metal panels from about 3/12 for exposed fastener panels, roll roofing from 2/12 with double coverage), install drip edge at the eaves, underlayment, then the covering from the bottom up, and finish the ridge or top edge. Work in dry weather, on a low, safe roof.Intermediate1 to 2 days
- Guide 4How to Install Roll RoofingRoll roofing is asphalt sheet roofing in rolls about 36 inches wide. Let it relax flat in mild weather, install drip edge, lay the first sheet at the eave, and either nail the laps (exposed nail method) or hide the nails under cemented laps (concealed nail method). In BC the building code sets minimum slopes of 3/12 for single-coverage roll roofing and 2/12 for double-coverage 19 inch selvage. Cement every lap, make end laps about 6 inches, and keep nails out of the exposed field.Intermediate4 to 8 hours for a small roof
- Guide 5How to Install a Polycarbonate Patio RoofTo install a polycarbonate patio roof, build a frame with a slope of at least about 1/12 (more is better), set purlins at the spacing the sheet maker specifies, lay sheets UV side up, drill fastener holes 1/8 inch or more oversized for expansion, fasten with washered screws without over-tightening, seal multiwall ends with tape, and flash the top against the house. Confirm all spacing with the sheet manufacturer.Intermediate1 to 2 days
- Guide 6How to Install Synthetic Slate and ShakeSynthetic slate and shake tiles are made from polymer or composite materials, and each brand has its own installation system. In general, install a suitable underlayment, start with the manufacturer's starter course, lay tiles with the stated exposure and offsets, fasten with the specified corrosion-resistant nails or screws in the marked zone, cut with the recommended tool, and blend tiles from several bundles. The manufacturer's instructions override every general rule.Advanced3 to 7 days for an average roof
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Specialty Roofing: Common Questions
What is the difference between cedar shakes and cedar shingles?
Cedar shingles are sawn on both faces, so they are thin, uniform and tapered. Shakes are thicker, split from the block, and have a rougher, more textured face. Shakes are laid with interlayed roofing felt between courses and wider keyways, while shingles are laid without felt interlay. Both need ventilation behind them to dry out between rains.
Can I put roll roofing on a house roof?
Roll roofing is mostly used on low-slope sheds, garages and outbuildings, where it is an economical covering. It is less durable and less attractive than shingles, and the exposed nail method has more places for water to get in. On a main house roof, shingles or a membrane system give a longer life and better performance.
How long do polycarbonate patio roofs last?
Lifespan depends on the sheet quality and whether it has a UV protective layer on the sun-facing side. Quality sheets installed with the UV side up, with oversized fastener holes and sealed edges, commonly last well over a decade. Sheets installed upside down or fastened tight without room for expansion often crack or yellow early.
Do synthetic slate and shake roofs need special installation?
Yes. Each product has its own exposure, fastener type, fastener position and underlayment requirements, and warranty coverage depends on following them. Some need to be installed in a particular sequence or with specific starter courses. Always use the installation instructions for the exact product, not those for a different brand or for asphalt shingles.
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Call 604-728-0146More How-To Categories
- Asphalt Shingles (18)
- Metal Roofing (18)
- Torch-On Roofing (9)
- EPDM Rubber Roofing (8)
- TPO and PVC Roofing (8)
- Flat Roof Details (8)
- Flashing Details (16)
- Roof Valleys (8)
- Chimneys (10)
- Skylights (9)
- Ventilation and Attics (10)
- Tear-Off, Decking and Underlayment (10)
- Roof Edges, Fascia and Soffit (6)
- Roofing Tools (17)
- Roof Safety Setup (6)
- Roof Repair (10)
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