Key Takeaways -

• Properly felting a shed roof helps protect against water damage and extends the shed's lifespan.
• Use quality materials, measure accurately, and allow for overhangs for the best results.
• Regular inspections and minor repairs can prolong the life of a felted roof.
• Removing old felt before installing new felt ensures a smoother, longer-lasting finish.

A garden shed roof needs protection from rain and weather to stay in good shape. Felting the roof is an easy and affordable way to keep your shed dry and extend its life.

This step-by-step guide will show you the tools, materials, and steps you need to felt a shed roof, whether it's flat or sloped. You'll also get simple tips for measuring, securing, and finishing the felt for a strong, weatherproof roof.

Keep reading to learn how to complete this DIY project and protect your old or new shed from the elements. A properly felted roof will keep your shed looking good and shield it from rain and wind for years.

Preparing the Shed Roof

Checking the Condition of the Existing Roof

Start by inspecting the roof for any signs of damage or rot. Look closely at the boards to make sure they are sturdy and free from decay. If you find any damaged sections, repair or replace them before moving on. This step ensures a solid foundation for the new felt.

Additionally, check that the roof boards are completely dry, as moisture can cause problems later on. It’s best to choose a warm, dry day for this project to avoid trapping moisture under the felt.

Removing Old Felt (if necessary)

If there’s old felt on the roof, carefully remove it before starting. Use a claw hammer or similar tool to pull up the felt, being sure to take out old nails or staples that were used to secure it. Once the old felt is gone, clean the roof’s surface thoroughly.

Remove dirt, debris, or leftover adhesive to ensure the new felt sticks properly. This will help create a smooth, even surface for the new roofing felt installation.

Calculating the Amount of Roof Felt Required

Measuring Different Roof Types

For Flat Roofs

To calculate the amount of felt needed for a flat roof, simply measure the length and width of the roof. Multiply these measurements to get the total area in square meters or feet. This will give you the base amount of felt required.

Be sure to add extra for overhangs to ensure proper coverage. Aim for at least 50mm (2 inches) on each side to provide added protection against rain and wind.

For Apex Roofs

For an apex roof, measure each slope separately. Multiply the length by the slope height to get the area for one side, then double it for the total roof area. Remember to allow for overhangs: add 50mm (2 inches) on the eaves (longer sides) and 75mm (3 inches) on the gable ends (shorter sides).

This ensures the shed roofing felt will cover the edges securely, preventing water from getting underneath (1). Now that you have the measurements, it’s time to start felting the roof.

Step 1 – Preparing the Felt

Roll out the roofing felt on a flat surface and allow it to sit for about 30 minutes. This step helps flatten the felt and makes it easier to work with during installation.

While waiting, measure the roof dimensions and cut the felt pieces to the appropriate size using a straight edge, allowing for overhangs. Leave at least 50mm (2 inches) on the eaves and 75mm (3 inches) on the gable ends.

Preparing the felt this way ensures you have the right coverage, saves time, and reduces the need for adjustments during installation.

Step 2 – Installing the First Layer

Begin by positioning the first piece of felt along the lowest edge of the roof. Secure it with clout nails, spacing them about 100mm (4 inches) apart along the top and around 300mm (12 inches) apart along the bottom edge.

Make sure the felt is stretched tight and lays smoothly across the roof surface. Avoid folding the felt under the roof edge, as this can create gaps that allow water to seep in, reducing the felt’s protective effectiveness.

Step 3 – Overlapping and Nailing Subsequent Layers

Continue to work your way up the roof, starting from the lower side and moving upwards. Overlap each new piece of felt by at least 75mm (3 inches) to ensure proper coverage and create a tight seal that prevents leaks.

For added security, consider using roofing adhesive along the overlaps before nailing down the felt. This step is especially useful in windy areas where felt might lift. The adhesive helps hold the felt in place and enhances the roof’s resistance to harsh weather.

Step 4 – Felting the Ridge (for Apex Roofs)

When dealing with apex roofs, apply the final piece of felt over the ridge so that it covers both sides evenly. Leave equal overhangs on both sides for proper coverage. Secure the felt with clout nails spaced at 100mm (4 inches) intervals along the ridge.

This will protect the roof’s most vulnerable area from water and wind, helping to keep the entire structure watertight and ensuring that rainwater flows down both sides without getting trapped.

Step 5 – Securing the Gable Ends

At each gable end, cut the felt at the centre, then fold it down neatly over the edge of the roof. Secure it with clout nails spaced every 100mm (4 inches) for a firm hold. If you have fascia boards, install them over the folded felt to hide any excess material and provide a polished finish.

This not only improves the appearance of the roof but also adds extra protection against moisture getting underneath the felt, which can cause damage over time.

Step 6 – Securing the Eaves

For sheds without fascia boards, wrap the felt under the edge of the roof and secure it with clout nails, ensuring it stays firmly in place. If fascia boards are present, make sure they cover the overhanging felt for a tidy look and extra protection.

This step helps keep the edges sealed and prevents water from seeping in underneath, providing a longer-lasting barrier against the elements. Make sure the felt is trimmed neatly to avoid loose ends that could get caught by the wind.

Final Touches

Trimming Excess Material

Once all the shed roof felt replacement is secured, use a utility knife to carefully trim away any excess material. Follow the roof’s edges to ensure a clean and neat finish. Make sure to cut close to the roofline without leaving any loose ends that could catch the wind or allow water to seep in.

A tidy trim not only improves the appearance but also helps maintain the felt’s protective function.

Inspecting for Loose Areas

After trimming, inspect the entire roof for any gaps, loose sections, or areas where the felt isn't fully secured. Use clout nails to fix any problem spots, making sure everything is tightly in place. This extra check ensures your shed roof is fully protected and ready to handle all weather conditions.

Frequently Asked Questions

Can You Felt a Shed Roof in Cold Weather?

Yes, you can felt a shed roof in cold weather, but it's not ideal. Cold temperatures can make the felt stiff and difficult to work with, which may affect the quality of the installation.

If you must work in colder conditions, try to choose a day that’s dry and not too windy and warm the felt indoors before starting. It's also recommended to use adhesive for extra security in cold climates.

How Often Should a Felted Shed Roof Be Replaced?

A felted shed roof typically lasts between 10 and 15 years, depending on the quality of the felt and local weather conditions. Regular inspections can help identify any wear and tear that may require repairs to extend its life.

If the roof shows signs of significant damage, such as cracks or leaks, it may be time for a full replacement. Proper maintenance can help delay the need for a new roof.

Conclusion

In conclusion, felting a shed roof is a straightforward and cost-effective way to protect your shed from the elements and extend its lifespan.

By following the whole process carefully—preparing the surface, measuring accurately, and securing the felt properly—you can ensure a durable, weatherproof felt roof. Regular maintenance and timely repairs will keep the roof in good condition for years.

With the right materials and techniques, even a DIY enthusiast can achieve professional results.

Sources -

1. https://www.roofingsuperstore.co.uk/help-and-advice/product-guides/flat-roofing/roofing-felt-buyers-guide/