How to Felt a Shed Roof

Contents:

• Choosing roofing felt
• Tools & materials
• How to prepare your roof
• How to lay roofing felt
• Fitting roofing felt around corners & edges
• Applying roofing felt on different roof types
• Key considerations
• FAQs

Felt gives garden sheds a simple but vital layer of protection against the elements. Felt protects your shed from rain, wind and UV light, and it reduces the amount of condensation that builds up inside. All of this keeps your shed and everything you store inside it in good condition.

In this article, we’ll give you a straightforward step by step guide for how to felt a shed roof. First, we’ll explain what the different types of felt are so you can find a cost effective and reliable type of felt. After that, we’ll explain how to measure, cut and fit roofing felt.

Here are the different types of roofing felt you can use on your shed roof:

• Standard bitumen roofing felt – Standard roofing felt is made from a layer of fibreglass or organic fibres that is coated with bitumen. A layer of mineral materials is added to the surface to add UV protection. These are a budget but perfectly effective option that normally last 5 – 15 years.

• Polyester backed bitumen roofing felt – This is made from polyester that is coated with a layer of bitumen and mineral materials. Polyester backed bitumen roofing felt is harder wearing and longer lasting than standard roofing felt. Normally, this type of felt lasts for 10 -20 years. It is, however, more expensive than standard bitumen felt.  

• EPDM shed roofing kits – EPDM shed roofing kits are made from a single sheet of EPDM that is made to fit a shed of a certain size. These are easy to fit, and they’re much longer lasting than bitumen roofing felts. Some come with 20 year manufacturer guarantees. They are, however, more expensive than other types of felt.

You can also buy felts in different thicknesses, and thickness has an impact on the durability of the felt.

Self adhesive and torch on felts should not be used on shed roofs.

 Here are all the tools and materials you need to felt a shed roof:

• Roofing felt

• Step ladder – for working safely on your shed roof

• Tape measure – for accurately cutting felt to size

• Claw hammer – for removing old nails in old felt and fitting new nails

• Clout nails - for attaching the felt to the roof

• Galvanised nails – to attach trim onto the front and sides of your shed

• Staple gun (optional) – to temporarily secure felt in place

• Stanley knife or heavy duty scissors – for cutting felt to size

• Roof felt adhesive (optional) - for securing roof felt at joints and edges

• Paint brush or roller – to apply adhesive

• Wooden batten – for securing felt at the edges

Before you fit your new felt, you need to get rid of any old felt and make sure your shed roof is ready for a new layer.  

Remove old roofing felt  

You need to remove all the old felt and any adhesive or nails that hold it in place before you start. It’s important to do a thorough job so you lay your new felt on a flat and smooth surface. Old nails and sharp edges can tear felt, and new felt can also end up cracking or becoming damaged if it is laid on uneven bits of old felt or adhesive.

Check the roof structure

Check the roof structure at this point to see if it needs any repairs before you start. There might be decayed pieces of wood that need replacing, or the structure might need to be made more secure.

It’s also a good idea to give the roof some time to dry before you fit your new felt.

After you’ve made sure your shed is ready, you can lay your new felt.

In this section, we’ll explain how to lay roofing felt on a typical apex shaped shed fitted with three sheets of felt.

If your shed is a different size or shape, you can follow the same fitting instructions. You can also check ahead to where we’ve given fitting instructions for all types of shed.

Step 1. Measure and cut the roofing felt

First of all, measure the length of your shed with your tape measure and cut three sheets of felt to the right length.

You always need to leave an extra 75 mm overhang at each end of the shed, so cut each sheet 150 mm longer than the length of the shed.

Always double check your measurements. You don’t want to cut a sheet too short and waste felt.

Step 2. Position the sheets on either side of the roof

Place one sheet of felt on the bottom part of one side of the roof. Position it so there is a 75 mm overhang at either end and a 50 mm overhang along the bottom edge of the roof. Having a staple gun can be helpful for temporarily holding it in place.

Once it’s correctly positioned, secure it in place with clout nails along the entire top of the sheet. Space the nails 150 mm apart along the entire top. Then run your hands over the sheet to make sure it’s sitting flat against the shed roof.

You do not need to fit the nails that hold the felt in place at the bottom until after you’ve put all three sheets in place.

After you’ve done the first sheet, repeat for the other one on the other side of the roof.  

Step 3. Position the top sheet of felt  

The next part of how to lay roofing felt is fitting the third sheet. This one runs along the ridge of the roof and overlaps the other two sheets.

Lay the sheet along the ridge, and position it so there is a 75 mm overlap at each end and so it overlaps both sheets on the sides by an equal amount. There should be at least 50 mm overlap between sheets. If there is an excessive overlap, you can cut the sheet to a narrower width. Allow the sheet to have some time to settle and smooth it over with your hands.

After you’ve positioned it correctly, temporarily secure it in place with staples or 4 clout nails.

You can add adhesive where the sheets of felt overlap if you would like to add extra durability. Otherwise, fix the sheet in place by putting in clout nails along both edges, where the top sheet overlaps the bottom sheets. Place nails every 150 mm.

Step 4. Secure all felt along the edge of the shed with nails  

Next you can nail all the felt in place along the entire edge of the roof.

You’ll need to make a slit in the top sheet of felt at the apex of the roof before you start. After this, go around the entire edge of the roof, pulling the felt taught and placing a nail every 150 mm to secure in place.

If you’d like to, you can also use roofing adhesive to create a more durable bond at the edges of the roof.

Fold the felt neatly at the corners.

Step 5. Trim and secure the edges 

The final step is to fit any trim your shed has at the ends and along the edges.  

Position the trim in the correct place and attach it with galvanised nails. Trim makes the edge look neater and helps to hold the felt in place.

A lot of sheds only come with barge boards for the ends. You can buy wooden battens and fit it at the edges for a neater look if your shed doesn’t have any trim on the edges.

After all the trim is in place, use your Stanley knife to cut off any excess felt that is protruding from underneath the trim. 

Sometimes, it’s tricky to work out how to fit roofing felt neatly around edges and corners.

Here are some pointers:

• Use adhesive for a stronger bond and a better seal at corners and edges.

• Smooth the sheets over and pull them taught before you fix them in place with nails.

• Cut a slit in the felt at the apex before you fold over and secure the felt at ends of the shed.

• Try to avoid cutting the felt at the bottom corners. Instead, fold the felt inwards and downwards so water runs off more easily and use a nail to hold the fold in place. Try to hide the fold under trim.

• Put trim back and add wooden batten along the edge for a neater finish and to prevent peeling.

Before you fit any felt, you need to plan how to apply your roofing felt according to the type of shed you have.

Apex roofs

Most sheds in the UK have an apex shaped roof. The number of pieces of felt you need depends on the width of the shed. 

• Standard width - Most apex shaped sheds are the right width for three pieces of felt. You lay one piece on each side of the roof, starting at the bottom. This leaves a gap in the middle, either side of the roof’s ridge. Then you lay a third piece along the ridge of the roof that covers the gap and overlaps the other two pieces.

• Wide sheds - On wide apex sheds, you might need to lay more than one sheet of felt on each side of the roof. This is fine. Just make sure you start at the bottom and work upwards, so the sheets that are higher overlap the ones lower down.

• Smaller sheds - On some smaller apex roof sheds, one piece of felt will be wide enough to overlap the top of the roof. You can fit these sheds with two sheets of felt. Just lay them over the top of the roof, and aim for a minimum of 50 mm overlap between the sheets.

Sloped roofs

Sloped roofs are very simple. You simply start with the sheet of felt at the bottom of the roof and work upwards. Make sure you overlap the higher sheets over the lower sheets so that water flows off the roof.

Aim for a minimum overlap of 50 mm between each sheet, and cut the final sheet to size when you reach the top of the roof.

You can buy EPDM garden roofing kits that are made to fit the exact size and shape of your shed. You don’t need to plan how to apply your roofing felt with these kits. Simply purchase the kit and follow the instructions for your shed.

Felting a shed roof is a simple job. Even if you don’t have much DIY experience, you can work out how to fit roofing felt. Just make sure you plan carefully for your shed and you pick the type of felt you’d like.

When you’re working, make sure you double check your measurements before you cut, so you don’t end up wasting any felt. Always make sure you work from the bottom up and overlap felt in the right direction as well so water always flows off your roof. Always check for loose areas on the felt as well, particularly around the edges and at folds. Be gentle with bitumen felts while you’re working as well because they can tear. 

Try to do occasional maintenance to your shed roof as well to prolong its lifespan.