How To Felt A Shed Roof?

How To Felt A Shed Roof
Felting a shed roof 1. Lay your first piece of felt Lay your first piece of felt across the bottom of the slope, leaving the overhang mentioned above, then nail in the top edge with the galvanized clout nails, leaving 50mm gaps. Fold the edges of the felt and nail them into place using clout nails.2.

Do I need adhesive for shed roof felt?

Why Felting A Roof Is Important – Made from a compressed cloth fibre base soaked in bitumen, shed felt is one of the most important components of your garden shed. The bitumen is the secret to its importance, as the substance makes the felt, and therefore your roof, waterproof.

Considering the amount of rain that we get in the UK, to say nothing of the snow in winter and early spring, a properly waterproofed shed roof is essential. It is not enough to slap a few pieces of new felt over the old felt with a bit of glue, nor should you forgo the use of nails and glue all the felt down.

If you want to install the product successfully, you will need to remove all the old felt, sort out any problems with the roof timber, and then use clout nails as well as adhesive where required. Do not worry about the holes made by the nails allowing water into your shed.

  1. If you do not use too many nails, the bitumen will seal around them.
  2. The reason you should use adhesive sparingly is because the bitumen in the shed felt will expand in warm weather and it will contract in cold weather.
  3. Not using too much adhesive allows it some give, which prevents it from tearing or cracking.

If you install new standard Green Mineral felt correctly, you probably will not need to replace it for at least five years, although you can extend that by applying an underlay. Other types of more durable felt can have a lifespan of up to 15 years.

How many layers of felt do I need for a shed roof?

2. Calculate the roof area – Next, measure the surface of the shed roofing to calculate how much felt you’ll need – don’t forget to add an extra 5-7.5cm for overlaps at the edges and the gables. Generally, if felting a pitched shed roof you’ll require 3 pieces of felt – 1 for each side and then one to overlap the two edges, but this may vary depending on the size of the shed roof and the width of the felt rolls.

Can you felt over old felt on a shed roof?

It’s best to tear down to the bare roof deck so you can also check for any decking damage. But you can also add another layer of felt on top of existing. This will add additional thickness to the roof, so be sure that fasteners (nails) are long enough to penetrate both layers.

Do you nail or staple roofing felt?

Roof underlayment installation, roofing felt, or “tar paper,” is an important step when roofing a building. Here’s how to do it. –

  • Total Time: 6 hours
  • Skill Level: Intermediate

Before applying roofing, you’ll need to cover the sheathing with roofing felt, also often called “tar paper.” Most local codes call for using 30-pound felt. Some roofers prefer to attach felt underlayment with one-inch roofing nails,or special nails with plastic washers, but most codes allow staples, which are easier to drive.

For the lower portion of the roof—especially the part that overhangs the eaves and is susceptible to ice dams—it’s a good idea to apply self-stick waterproof shingle underlayment (WSU), also called ice guard. Underlayment, flashings, and shingles all work together and must be installed in the correct order.

If you lay the felt perfectly straight, you can use its lines (instead of horizontal chalklines) to align the shingles. Do not use felt as a temporary protection against rain: If it gets wet it will wrinkle, making it harder to shingle. If you need to temporarily protect a roof, cover it with plastic sheeting or a tarp.

What can I stick roof felt down with?

Answer: The Bostik Bituminous Felt Adhesive Black is a solvent based bitumen felt adhesive designed for bonding bitumen based roof felt to various substrates including mastic asphalt, existing roof felt, underfelt and concrete.

Do you nail down roofing felt?

Let’s get started. –

Take a width measurement of your roof, adding 50-75mm to each side to allow for the overhang of the felt. Use a spirit level or straight edge to scratch a marking into your felt. Cut your felt to size along the marking using a Stanley knife.

Attach your felt with galvanised clout nails – these are shallow enough not to go through the roof. Use temporary nails to hold the felt while you tack it down properly. The nail distances should be roughly 6-7 inches apart. Work slowly and keep things neat. Keep yourself safe by ensuring that if you need to stand on the shed or roof that you support yourself on the strongest load bearing areas.

How To Felt A Shed Roof galvanised clout nails

If you are working on a shed roof, tack the felt over the edges of the lip of the roof.

For the corners, use a pig’s ear fold and hold in place with a longer nail. This will leave you with a neat corner.

If you’re doing a pitched roof, you will want to ‘cap off’ the peak. Use felt adhesive to glue down, and then tack with nails as you did before.

How To Felt A Shed Roof felt adhesive

Trim off any excess polythene and replace the trims.

If you’re laying a flat roof, you will want to do three layers for additional protection; a felt underlay, a second bonded underlay adding gutter drips, and finally a top bonded layer. Finish by felting and edges and flashings. Each layer is bonded using the specialist adhesive and by following the manufacturers instructions with regard to application and timings.

Does shed roof need to be dry before felting?

How To Felt A Shed Roof Replacing your shed roof felt is one of those gardening jobs that tends to get pushed to the back of the queue (in our case it comes way behind cider-making, scrubbing demijohns and lounging around slurping sloe gin). But with the recent bouts of hurricane-related weather conditions that have been ravaging the UK, it’s possible that this task has shifted up on your list of priorities. It stands to reason, but take a look at the weather forecast and make sure you are in for a spell of dry weather before tackling your shed roof. Any damp patches that you uncover (see below) will need to dry out before laying down new felt. Rip it off Begin by removing the old roofing felt. Examine and replace Once you’ve relieved the roof of its shabby old skin, take a close look at the underlying timber. The removal of the old felt may well have revealed rotten planks and joists (an early indication of this would be the sagging and bowing of your shed roof).

  • Repair or replace before continuing your task.
  • Splash the cash Try to buy the best felt you can afford – ideally professional grade roofing felt – rather than the cheaper, tissue-thin varieties.
  • Look for felt that has been reinforced with polyester for a superior, weather-foiling finish that will last for years.
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Calculate Work out your roof area, making sure you add on extra for overlaps on joins and overhangs. Ideally, allow for a 50mm overhang on both the gable ends and sides. You’ll most likely need three rows of roofing felt to cover a small shed – one for each side, then one running across the apex, that will overlap the two pieces.

Measure your roof again, prior to cutting your felt, then roll out your felt on the ground and cut it to size using a trusty blade and a straight edge. Tack it down Lay your first piece of felt across the roof – rough side up – and smooth out any wrinkles, then crack open a packet of clout nails, especially designed for the job in hand.

These large headed nails will hold the felt secure and the shallow pointy end – typically 15-20mm mm long – will drive into the wood without penetrating the shed interior. Tack the felt at the central roof edge to prevent it sliding around whilst you straighten it up, then proceed to tack it into place, starting with the roof edges, followed by the gable ends. How To Felt A Shed Roof Cap it off Lay the final piece of shed roof felt over the apex, and tack into place using clout nails. If all goes to plan, the heads of the clout nails will sink into the felt to produce a watertight seal. It’s worth going around giving them an extra tap on the head, just to be sure. How To Felt A Shed Roof The Two Thirsty Gardeners, Rich and Nick, are bloggers who love gardening, eating and drinking in equal measure! They love to share tales from their allotment including their experiments turning the spoils of their crops into alcohol, both the good and the bad! To find out more about Rich and Nick, click here.

Can you put 2 layers of felt on a shed roof?

Step two – Now that you have a clear flat surface on which to install your shed roof felt. I normally lift the roll of replacement felt on to the roof with the roll going across the slope. This way I can get the correct length of material. I allow for the felt to over hang the depth of the roof structure and then an additional 25mm. How To Felt A Shed Roof Unrolling the shed felt on the roof deck To fit the felt, start at the bottom of the roof slope. Overhang the felt by the depth of the roof structure and an additional 2.5cm. The first sheet is secured in place by using the clout nails at approximately 50cm intervals along the top edge. How To Felt A Shed Roof The seams between sheets use nails at 5cm spacing. Most domestic shed roofs will require at most two runs of felt before they come to the ridge. Each run of shed felt should overlap the next by at least 7.5cm. Overlapping sheet, shed felt adhesive sticks, felt to felt. Not felt to timber. Stops capillary action up the slope and strong winds driving water up the roof slope in between the gaps.

Can you felt a roof yourself?

Felt is affordable and very lightweight, making it easy to install and repair, even for those who aren’t experienced in DIY. So, if you want to learn how to felt a flat roof, you’re in the right place. This guide is designed to teach you how to felt different types of flat roof, from garages to extensions.

How Long Does felt last on a shed?

How Long Does Shed Roof Felt Last? – Shed felt will typically last around 5 years. However, if you go for a shed with a polyester backed shed felt, this can last up to 15 years. Although polyester backed felt is the same thickness as standard, it is much stronger and more difficult to tear, so it lasts longer.

Can you cut roofing felt with scissors?

3. Cut The Felt to Size – By the time you have prepared the roof the rolled-out felt should already be ready to use. Carefully measure the roof and count an extra piece (4 inches or 10 cm) for effective coverage and use white chalk to mark where needs cutting. How To Felt A Shed Roof

How much does it cost to Refelt a shed roof UK?

The average cost of felt roofing per square metre is about £30 – £45. The roof felt cost for a medium-sized shed is around £250 – £450. Part of the cost of refelting a roof is the price of labour, which will cost around £200 per day.

Should roof felt be tight?

Fitting the felt – Starting at the bottom, run the felt along the roof and align the felt so that the lower edge extents over the fascia board by enough to reach the middle of the gutter. Starting at one end, nail the felt to the rafters using galvanised 25mm (1 inch) clout nails, put a nail in the middle of the width, and about 250mm (10 inches) in from the fascia on every other rafter (leave the top of the felt unsecured at this point).

  • Work along the roof taking out any excess slack in the felt, but do not pull it tight; a slight sag between rafters is ideal as it will allow any water to drain down the felt.
  • When the first length is complete, lay the next layer of felt on top of the first so that it overlaps by at least 100mm (4 inches) – horizontal overlaps (where one roll ends, and the next one is started) should be at least 150mm (6 inches).

Nail the second strip of underfelt to the rafters in the same manner as the first, with the lower nails positioned about 50mm (2 inches) from the edge so that it secures both this strip and the previously laid one. Repeat this sequence with further strips of felt up to the top of the roof.

At the ridge, take the underlay over the top of the ridge by at least 150mm (6 inches), then, when installing the top run of felt on the second side of a pitch roof, take the felt over the felt from the first side and nail it through to the top of the rafters on the first side. At a verge, lay the underlay about half way over the outer wall skin (or the outer rafter on an overhanging verge). Where the roof abuts to a wall, either at the side or top, trim the underfelt to allow about 50mm (2 inches) onto the wall. At a hip, take the underlay from the first side around the corner, and overlap from the second side by at least 150mm (6 inches). Make sure that all folds are done so that no pockets are left where would could collect.

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Does it matter what side of roofing felt goes down?

Download Article Download Article Roof felt, also known as tar paper, is a waterproof fiberglass product. It is used for temporary roofing, for weatherproofing, and as an underlayment under shingles or other permanent roofing materials. Whatever your reason for attaching roof felt, you should only do it after cutting your pieces to the appropriate size and cleaning and preparing your roof.

  1. 1 Calculate the area of your roof by combining the area of each surface. Start by measuring the length and width of one side of the roof in inches. Afterward, multiply them to calculate the area. For example, if its length is 120 inches (10 ft) and its width is 240 inches (20 ft), the area is 28,800 square inches (200 sq ft).
    • Add about 2 inches (5 cm) to each of your measurements before calculating the area. This will give you extra felt to hang over the eaves of your roof.
  2. 2 Purchase enough felt to cover your roof’s area. Convert the area from inches to feet prior to purchasing your felt. One roll of conventional #15 felt covers 432 square feet (40.1 m 2 ). However, you must allow for overlaps on joints. In most cases this will leave 400 square feet (37 m 2 ) of net coverage per 1 roll.
    • Purchase an extra pack of felt in case you need more or end up damaging your first roll.
    • Divide your area in square inches by 144 to get the area in square feet.


  3. 3 Cut the felt to size using a hooked blade knife. Unroll your felt onto a flat surface. Lightly scratch a vertical line on the surface with the rear of the blade to mark the length of your shed plus the front and rear overlaps. Mark the same at the other end of the roll.
    • For example, if the width of your shed is 240 inches (610 cm) plus 4 inches (10 cm) of overlap, mark a line 244 inches (620 cm) from the left width of your felt piece.
    • Purchase a hooked blade—which has a small hook extending from a standard blade—from a home hardware store. You can also use a standard straight blade if you don’t have a hooked blade. However, this will make cutting more difficult.
    • Be sure the flat surface doesn’t have anything sharp on it.
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  1. 1 Remove old felt from the roof with your hands and a putty knife. Grab loose pieces of felt and pull them off the roof with your hands. For pieces that aren’t coming loose, press a putty knife underneath it. Apply pressure and chisel away at it until it comes loose.
    • Pull out nails that are holding felt to the roof using the sharp end of a claw hammer.
  2. 2 Clean the roof decking of any debris, protruding nails, or other objects. Gently scrub the roof using a bristle brush, taking care not to damage it. Creating dents will make it harder for your roof felt to adhere to the roof. Use the sharp end of a claw hammer to gently pull out any crooked or protruding nails. Replace any removed nails with new ones.
    • Use coarse sandpaper (40- to 60-grit) to remove tough dirt.
  3. 3 Dry the roof surface using a towel after you’re finished cleaning. Scrub the wet spots with a small towel in clockwise motions. Never apply roof felt over wet or damp decking, as this condition will cause the decking to warp or buckle, and possibly rot.
  4. 4 Replace any damaged or rotten material on the roof decking. Remove any nails from the damaging decking using the sharp end of a claw hammer. Insert a square nose spade, shovel, or special scraper under the panel and lever the decking upward. Continue loosening it until it comes off or it’s loose enough to pull off with your hands. Install another base sheet of the same material.
    • Be sure to use the same nails to fix it to the wooden beams underneath.
  5. 5 Apply waterproof paint or primer to promote felt attachment. Use a 4 inch (10 cm) paintbrush or a roller to apply the paint or primer. Drag it gently from one end of the roof to the other (east to west or west to east). Begin at the bottom, working in horizontal lines and gradually moving upward.
    • If you use paint, be sure to choose high-quality water-based enamel acrylic brands with rust-inhibiting properties.
    • Select general purpose felt primer with low viscosity.
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  1. 1 Start rolling the first layer of felt out from the bottom of one side of the roof. Begin at the bottom-right or bottom-left of the roof. Afterward, roll the felt away from you lengthwise along the lower edge about 10 feet (120 in). As you roll it out, make sure that it remains flat.
    • Adjust the felt as you roll it, making sure that it’s straight with no bubbling.
    • Never install the felt vertically across your roof.
    • Hang the lower edge of the felt over the eave—the part of the roof that meets or overhangs the shed’s walls—by about 0.5 to 0.75 inches (1.3 to 1.9 cm).
  2. 2 Tack the felt onto the initial rolling spot using a tack gun. Return to the side that you began rolling from and apply 3 tacks vertically using a tacking gun. To load the gun, turn the front dial 180 degrees and insert a needle by lining up the long groove of the needle with the groove on the tack gun. Press the needle into place and then turn the lever back around.
    • Keep each tack about 2 to 3 inches (5.1 to 7.6 cm) from the edge of the roof.
  3. 3 Continue pulling the felt tight from the untacked end. With one side tacked to the roof, pull the opposite end tightly and hold it to the ground, making sure it lies flat on the roof surface.
    • Take care not to rip the felt as you pull it.
  4. 4 Roll a new row of felt into the opposite direction as the first. If you rolled the first row from west to east, the new row should be east to west. Allow about 4 inches (10 cm) of overlap between the bottom of the second row and the top of the first layer.
    • Apply each row in a perfectly parallel manner. Most roof felt pieces have guidelines stenciled into them to ensure you apply them in straight, parallel lines.
  5. 5 Continue rolling new felt rows until you are close to the roof’s peak. Once you get close to the top, add another layer of felt so that you overlap the ridge of your roof by about 1 foot (0.30 m). Afterward, apply the felt in the same manner on the opposite side.
  6. 6 Nail the felt in using 0.59 inch (15 mm) galvanized clout nails. Grip the hammer tightly by the end of the handle and hold your thumb at the top of the shaft. Start at one of the upper corners of the felt and continue along the perimeter. Space each nail apart by about 30 to 36 inches (76 to 91 cm) along the side of the felt closest to the roof’s peak and 12 inch (30.5 cm) along the side closest to the ground.
    • Small sheds usually require about 100 to 150 clout nails.
    • Be careful to drive nails flush. If the circular nail heads penetrate the felt they can cause leakage.
    • Remember that each nail must be long enough to pierce 2 layers of felt during across regions that overlap.
    • Simplex or plastic cap felting nails are also sufficient.
  7. 7 Cover all nail heads with roofing mastic for long-term roofing. If this felt is more than a temporary waterproofing measure, apply roofing mastic using a caulking gun, Hold the gun at a 45-degree angle with the nozzle pointed downwards. Pull the trigger of the gun and move the nozzle around the circumference of each nail.
    • Move at a steady, consistent pace to ensure even application.
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Add New Question

  • Question Do you need a blowtorch for felt? No, you only use that for applying the large sheet of granular roofing rolls. Install the first row along the edge of the house and then add the drip edge flashing. Continue up to the top with each each new row overlapping at least three inches. Then you can roll on the peel and stick underlay that will act as a vapor barrier and ice shield and finally, the shingles.
  • Question Is there a top or bottom on felt paper? Richard Cooke Community Answer It has to go rougher side up, but there is no specific top or bottom. Make sure the felt placed higher up overlaps the lower piece.
  • Question Do I need to spread a layer of tar on the roof before laying the felt? You don’t need to apply any tar before laying the felt, however it depends on your needs. You can go whole hog by sanding and priming the roof decking and then using a bituminous paint to stick the underlay felt down. Then use a second layer of top felt, again with bituminous paint, without having to use any clout nails. Of course, this could limit your options for replacing the felt at a later stage.

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  • Use a heavy-duty felt for long-term weatherproofing. Felt comes in either 15-pound or 30-pound ratings. The 30-pound felt is twice as strong as the 15-pound felt.
  • If the roof felt tears, cut a piece large enough to cover the tear with lots of overlap, slip the top under the next lap above it, and nail into place.
  • For a more permanent roof coverage, use roll roofing products, which are created with mineral aggregate coating to stand up to the elements for a longer period.


  • Use ladders with caution, and have someone available in case of accidents.
  • Never step on roof felt before it is securely nailed, as it may slide and cause you to fall off the roof.


  • Roof felt
  • Hammer
  • Utility knife (hooked or straight blade)
  • Paint or primer
  • 4 inches (10 cm) paint brush or paint roller
  • 100 to 150 15 millimetres (0.59 in) galvanized clout nails

Article Summary X To attach roof felt on a shed, start by calculating the area of your roof and buying enough felt to cover it. For easier cutting, unroll the material on a flat surface and use a hooked blade knife to cut the felt to the size of your shed’s roof.

Before you attach the new felt to your roof, use a putty knife to scrape off old pieces of felt and remove any old nails with a claw hammer. Then, scrub the surface with a bristle brush to clean it and use coarse sandpaper to remove tough dirt. When the roof is dry, use a paint roller to apply waterproof paint or primer to the surface to be the adhesive for the felt.

Start rolling the first layer of felt in the bottom-right or bottom-left corner of the roof, being sure to keep it flat as you roll it on. Continue rolling until you reach the roof’s peak, and then use galvanized clout nails to secure it in place. For more tips on adding new roof felt to your shed, like how to cover the nail heads with roofing mastic, keep reading! Did this summary help you? Thanks to all authors for creating a page that has been read 535,455 times.

Does roofing felt go under drip edge?

Place the metal roof drip edge flashing along the gable ends – /CHOKCHAI POOMICHAIYA/shutterstock Once all the underlayment is applied, go back and place the roof drip edge flashing along the gable ends of the roof. Covering the ends of the ice-and-water barrier or felt paper with drip edge ensures that windblown rain that gets under the shingles will run over the underlayment, not on the sheathing.

Why do you put gravel on a felt roof?

Gravel flat roofs and pea shingle flat roofs – Gravel and pea shingle have two primary purposes on a flat roof; they provide a ‘loading coat’ and they afford UV protection. As ballast, the gravel will help anchor the material underneath and lower the risk of it being blown off in high winds.

Do you have to use adhesive with roofing felt?

Can Roofing Felt be Glued? – Roofing felt products should not be glued to the decking in lieu of using nails or screws. However, on low-slope roof applications from 2:12 to 4:12, roofers may use adhesive on felt. If you have a low-slope roof, your roofer may need to use roofing felt adhesive to bond together multiple layers of roofing felt or to secure sections that overlap.

Can you stick roofing felt to wood?

From Everbuild, this Black Jack Roofing Felt Adhesive is a black oxidised bitumen-based cold felt roofing adhesive that is cold applied. It is perfect for bonding roofing or gluing roofing felt to itself, concrete, asphalt, metal, wood and comparable surfaces.

Do you have to use adhesive with roofing felt?

Can Roofing Felt be Glued? – Roofing felt products should not be glued to the decking in lieu of using nails or screws. However, on low-slope roof applications from 2:12 to 4:12, roofers may use adhesive on felt. If you have a low-slope roof, your roofer may need to use roofing felt adhesive to bond together multiple layers of roofing felt or to secure sections that overlap.

What is the best way to adhere felt to wood?

What to Look Out For in the Best Adhesive for Gluing Felt to Wood – Tacky glue is the best adhesive for felt to wood; another alternative is permanent glue like super glue or spray glue if you are working on a larger project. By using the correct glue for your project, you will guarantee that the felt and the wood will not be damaged, and the bond created will be effective.

What nails do I need for shed felt?

How long should the clout nails be? – A typical shed roof deck will be made from roof boards or OSB that are about 12mm thick. So, using 13mm nails will be the most secure. This allows for the maximum nail penetration, without going through the roof to the underside. How To Felt A Shed Roof Two different lengths of clout nail (with coin for scale)