Roofing felt is the go-to material for protecting garden sheds from rain, snow, and UV damage. But with so many options on the market, choosing the right one and installing it correctly can be tricky. This guide covers everything you need to know about garden shed roofing felt – from types and thicknesses to step-by-step installation and common pitfalls. Whether you're building a new shed or re-roofing an old one, you'll find practical advice to get the job done right.
Types of Garden Shed Roofing Felt
Roofing felt for sheds typically comes in three main types: sand felt, mineral felt, and torch-on felt. Sand felt has a smooth surface with sand embedded to improve grip and weather resistance. It’s lightweight and easy to handle, making it a popular choice for DIYers. Mineral felt has a layer of colored mineral granules that add durability and UV protection. It looks more attractive and lasts longer than sand felt. Torch-on felt (also called modified bitumen) requires a propane torch to melt the underside and bond it to the roof. It provides excellent waterproofing but is more challenging to install. For most shed roofs, mineral felt offers the best balance of durability, appearance, and ease of installation.
Key Specifications: Weight, Thickness, and Coverage
When buying roofing felt, pay attention to the weight per square meter. Heavier felts (around 28-35 lbs per square) are thicker and more durable. Lighter felts (18-22 lbs) are cheaper but may tear more easily and have a shorter lifespan. Thickness also matters – look for at least 1.5 mm for decent protection. Coverage is usually measured in squares (100 sq ft per square). A typical 8x6 ft shed roof might need about 1.5 squares. Don't forget to add 10% extra for overlaps and waste. Also check the roll length and width; common sizes are 36 inches wide and 36 feet long. Buying a single roll often saves money compared to multiple smaller rolls.
Step-by-Step Installation Guide
Installing roofing felt requires basic tools: a hammer, roofing nails, a utility knife, a tape measure, and a ladder. Start by ensuring the shed roof deck is clean, dry, and free of protruding nails. Lay the first strip of felt along the bottom edge of the roof, allowing a 2-inch overhang at the eaves. Nail it in place using galvanized roofing nails spaced every 6 inches along the edges and 12 inches in the field. Overlap the next strip by at least 4 inches over the previous one. Continue until you reach the ridge. At the ridge, fold the felt over and nail it on both sides. Trim any excess with a utility knife. For a neater finish, apply a bead of roofing sealant under the overlaps and around nail heads. Always work from the bottom up to ensure water runs off over the overlaps.
Common Mistakes and How to Avoid Them
One of the biggest mistakes is using too few nails or spacing them too far apart. This can cause the felt to lift in high winds. Another error is not allowing proper overhang at the eaves and gable ends – at least 1-2 inches is necessary. Some DIYers skip the sealant on overlaps, leading to leaks. Also, avoid stretching the felt too tight; it should lie flat but not be taut, as it can shrink and tear. Finally, never install felt on a wet or damp roof deck – moisture trapped underneath will cause rot and blistering. Take your time and follow the manufacturer’s instructions for best results.
FAQ
Q: How long does shed roofing felt last?
A: With proper installation, sand felt lasts about 5-7 years, mineral felt 10-15 years, and torch-on felt up to 20 years. Climate and roof slope also affect lifespan.
Q: Can I install new felt over old felt?
A: It's not recommended. Old felt may have wrinkles, tears, or trapped moisture. Removing the old layer ensures a smooth, dry surface for the new felt.
Q: Do I need underlayment?
A: For most sheds, a single layer of roofing felt is sufficient. If your shed has a low slope (less than 15°), consider using an underlayment membrane for extra protection.
Q: What type of nails should I use?
A: Use galvanized or stainless steel roofing nails with a large head (about 1/2 inch). They resist rust and hold the felt securely. Avoid common nails as they can pull through.
Final Tips for a Long-Lasting Roof
To extend the life of your shed roof, inspect it annually for damage, especially after storms. Trim overhanging tree branches that can drop debris or rub against the felt. If you notice small tears or lifted edges, repair them promptly with roofing cement. Consider applying a reflective coating if your shed gets direct sun – it reduces heat buildup and UV degradation. And remember, investing in quality felt and taking time during installation will save you from frequent repairs. Happy building!