How to Repair a Shed Roof

Unlike our homes, which often receive regular care and attention, the shed tucked away at the back of your garden can often be forgotten. Left to the elements and the ravages of time, a shed’s roof can deteriorate. If left unrepaired, it could even become dangerous – and expensive to sort!

Table of Contents

Common Issues with Shed Roofs

Leaks

Leaks are the number one reason why shed roofs will need repairing. Due to their lightweight construction, sheds cannot bear as much weight as other structures. Roofing materials such as felt, bitumen or plastic are all common shed roof coverings as they’re easy for homeowners to install, but this comes at the price of durability and longevity. Cracks, tears, missing shingles or just general wear and tear can all lead to roof leaks. Not only do these present the danger of structural damage, but the resulting mould and mildew could pose serious health risks.

Sagging

An issue that’s very easy to identify, a sagging shed roof can cause a lot of anxiety. A small amount may not mean that you’re in immediate danger, but it’s important to address the issue quickly. Reinforcing and repairing a sagging shed roof will prevent catastrophic issues such as collapse. Sagging is often caused by excess weight on your roof’s surface. As stated, shed roofs are not designed to carry much weight, so any debris such as snow left unaddressed can quickly cause harm.

Exposed Timber/Aged Roofs

An aging or otherwise unmaintained roof will not only look unpleasant but can lead to both leaks and sagging. Aside from the structural benefits, refurbishing, repairing or replacing your shed roof will add value to your property, and a lovely shed will only help to entice any buyers pottering around your garden.

Repairing Your Shed Roof

A quick safety tip when working on your shed. You should always check the inside first to determine the weakest and strongest part of your roof, meaning which areas will not be able to take your weight and which are loadbearing. Appropriate safety measures should be taking when working at any kind of height.

Repairing a Shed Roof Leak

How to Repair Shed Roof Felt?

Torn, damaged shed roof felt, when left alone, can allow water ingress, which will not only damage your shed but also anything left inside. Fortunately, patching up these tears can be done quickly and easily with only a few tools. You’ll need: A hammer, tape measure, screwdriver, utility knife, tacks, ladder and of course some new roofing felt suitable for your shed roof.

  • The first step is to remove your shed finials and fascia boards. These will likely be either screwed or nailed on and should be simple to remove using a hammer or screwdriver. Put these boards to the side and keep them safe. If the boards are suffering from rot, you can also take this opportunity to source replacements.
  • Next untack and remove the damaged felt. The nails holding the felt in place should be easily pried off with a flat-headed screwdriver, though you should be extra careful when doing so to avoid further rips and tears.
  • Measure the length of your shed roof and cut the new felt to an appropriate size. When cutting ensure that you allow a two-inch overlap on all sides, when your new piece of felt is prepared, compare it to your roof to make sure it is the correct size and adjust, as necessary.
  • Smooth out and nail down the new piece of felt. Nails should be placed at 6 inch intervals.
  • Re-affix your fascia boards and finials and the job is done. If you are using new timber, remember to treat it first with preservative to increase its lifespan.

Now that your shed roof has been repaired, be sure to perform regular checks and maintenance to prevent the need for expensive repairs in future.

How to Repair a Shed Roof Ridge?

The exact method for repairing a leak in the ridge of your apex shed roof will largely depend on the material used. However, no matter the shed roof material you have, the process is largely the same.

For felt roof ridges, any damage can be repaired in much the same way as a repair to any other part of a felt roof. You could also consider using a suitable sealant to ensure a secure, waterproof seal. With shed roof shingles, tiles or roofing sheets, the roof ridge will likely be made from a strip of material or individual ridge pieces. In this case, leaks will likely be caused by a tear, crack, or other damage to an individual piece. If this is the case, all you may need to do is simply replace this piece. You should also inspect the timber below for damage however, as water-damaged timber can quickly suffer from damp or rot.

Depending on the size of the crack in your roof ridge, sealants are available for both wood and bitumen roof ridges, as a relatively inexpensive repair option that also provides quality waterproofing. When applying sealant, first ensure that the area is clean and dry, and that you’re wearing the right PPE such as gloves. When using an application gun, squeeze the trigger gently and move the gun in a smooth motion to ensure a clean and neat finish.

How to Repair a Pent Shed Roof?

Leaks in a pent roof shed are largely repaired using the methods already mentioned. Once the section of roof that’s causing the leak has been identified (either the section of felt, or individual shingle, tile, or roofing sheet), it should be removed and replaced. Whenever you’re replacing roofing materials, it’s important to use the correct fixings to ensure a secure fit. It may be possible to use some of the fixings from the damaged roof sections you’re removing, but this isn’t always possible. Always check the quality of any fixings you re-use, or you may soon find yourself in need of yet another replacement.

Repairing a Sagging Shed Roof

As soon as you’ve noticed your shed roof beginning to sag, fixing it should be at the top of your to-do list. You should first identify what the initial cause of the sagging was. If it was pooling water or other water damage, you’ll know this by the fact that the rafters are damp. You should then refer to our previous section on repairing shed roof leaks. We’ve also got a fantastic guide to waterproofing a shed from top to bottom, which you may find invaluable.

Roof sagging related to excess weight is simple to deal with. All you need to do is clear away the debris. You could also consider switching to a more lightweight roofing material, as this will lighten the burden placed on your shed’s structure.

Once you’ve dealt with the root causes of your sagging shed roof, you can move onto repairing the sag itself. This is generally done by providing extra support to the inside of your shed roof. Fitting new rafters, particularly if your existing ones have been damaged by water ingress, along with installing new purlins, struts and angle brackets are all good choices. Remember, it’s best to sort a sagging shed roof out sooner rather than later, as a collapsed roof will be many times more expensive and difficult to deal with.

Replacing Your Shed Roof

Unfortunately, in some cases, simply patching up a tear or sealing a gap in your shed roof simply won’t be enough. The best way to repair your shed roof may be to fully replace it. On the bright side, this is a fantastic opportunity to breathe new life into your garden shed by protecting it with a higher-quality, lower-maintenance roof that will last longer.

How to Replace Roofing Felt?

One of the cheaper options, high quality polyester felt can still provide long lasting protection thanks to its internal reinforcement. The first step of course, is to remove the old layer of felt. More often than not, this will be lower quality felt which has either been nailed down, glued, or hot bonded.

First things first, all trims such as finials and bargeboards should be removed carefully and placed to one side, ideally keeping as many of the fixings as you can intact for later use. If your shed has a ‘nailed on’ felt roof, these nails can be levered up using a pry bar or claw hammer. The felt can then be lifted off. Hot bonded roofs take a little more effort to strip off, but it’s simple enough to peel away the material using a flat spade. Once your shed roof has been stripped, the final step is to check the surface for any remaining nails, which should also be removed if found.

Fitting a brand new felt roof on a shed should take most DIYers a few hours. When measuring and cutting this felt for your roof you’ll want to add and extra 50-75mm at both the front and back ends to allow for an overhang which can be nailed into the verge. Similarly, when fitting the felt at the eaves you should leave an overhang long enough that it goes past the timber, so that rainwater will not run down the shed’s walls. Nails should be fitted at roughly 150mm centres at the top and bottom parts of your roof and at 50mm centres across the verge and eaves. If you are working on an apex roof two matching pieces of felt should be installed on either side. The ridge (or highest point for pent sheds) should be left clear for a separate piece of felt.

Again, when cutting this piece, you should allow for some overhang across the front and back of your shed as well as over the piece or pieces of felt already fitted. This is so the ridge piece can be secured to the main section(s) of roofing felt using felt adhesive to create a strong seal. Nails should then be used to secure the ridge piece to the roof deck, again at roughly 150mm centres.

The edges of the felt can be curled or cut to fit around the corners and again, secured with a nail. Once the roof has been properly secured, trims can be re-affixed, hiding any rough edges for a clean, professional finish.

How to Replace Shed Roof Tiles or Shingles?

Offering a similar level of protection to felt, but with a much more appealing aesthetic. Shingles and tiles are perfect for homeowners that want to make their sheds look fantastic. A lot easier to replace than felt roofs, some plastic tiles (which are more suited to sheds due to their light weight) have been designed as strips, moulded to fit together perfectly with minimal fixings. This means that most can be replaced quickly simply by removing the fixings, sliding out the damaged tile or tile strip and then fitting the new one it its place. The methods for replacing more traditional tiles will depend on the profile of that tile (Plain, interlocking etc.) however in the majority of cases this can be done with the use of a flat ended prybar by carefully levering out the unwanted tile and sliding in the new one. Depending on the damage, it may be necessary to remove multiple layers of tiles for an effective replacement.

When replacing tiled ridge pieces, you could also consider using roof putty as a gap filler. It can be used straight out of the box, and being watertight and weather resistant may prevent the need to replace any other tiles in the future.

To replace roof shingles, you’ll first need to clearly identify which strip needs to be replaced. This is because it’s highly likely that the above layers of shingles will also need to be pried away from the roof deck to access the fixings. Once you’ve removed all of the nails connecting the damaged strip to the roof deck, pry the shingle away and simply slip your new shingles into place and fix them to the roof deck. If you’re concerned that this may not be secure enough, you could use a small amount of roofing sealant for added security.

How to Replace Bitumen Roofing Sheets?

Like plastic roof tiles, bitumen roofing sheets are fairly straightforward to replace. First remove the fixings, then the sheet itself, and affix your new roofing sheet in its place. You may need to cut the sheet to size yourself, which you should do using a handsaw that has been lubricated.

As with roofing felt, bitumen sheets should overhang at both the verges and the eaves, at most around 70mm over the eaves. It should overlap with the other sheets on the roof deck and be secured to verge with fittings at approximately 100mm centres if replacing the first sheet at the front of the roof or the last sheet at the back.

How to Replace a Flat Shed Roof

If you’ve got a garden shed with a flat roof, you should consider covering it with an EPDM membrane. Unlike roofing felt, which is prone to any number of issues, EPDM is installed in a single easy-to-fit sheet that will last decades with minimal maintenance. Cut to size and fitted to the shed roof, verge and eaves using a water-based adhesive, this flat roofing material, while not sharing the stylish qualities of tiles or shingles, offers unmatched reliability.