Shed Roof Repair: How to Do It in the Right Way

The first shed I ever built was absolutely bulletproof – it took me way too long to build and cost way more than I’d anticipated. But when it was done I knew it would last me at least the next fifty years. It took one good wind storm and some flying shingles to prove that I wasn’t exactly Mike Holmes.

So I had to learn how to do shed roof repairs. Did I need a shed roof replacement? Could I get away with not replacing the shed roof plywood? I wasn’t sure. But after some research, I realized this was one shed repair I could do without much difficulty.

We’re going to take a look at how to repair a shed roof, which is probably one of the most common shed repair jobs you’ll do. Whether you have a metal or tar paper shed roof, we’ll try and cover every possible material and problem you could have.

Shed Roof Repair

Types of Shed Roof Repairs

When you get down to it, there are hundreds of different types of repair you could do to a shed roof. But they fall into 3 basic categories: outer layers such as shingles and underlayment, sheathing or plywood, and roof rafters.

Hopefully, you don’t have rafter issues because that means the structural integrity of your shed is compromised – don’t go in it, particularly if there is a load of snow on top! Let’s have a quick look at each repair type.

Roofing and Underlayment Repair

If you have damaged shingles or underlayment, then you’ll probably first notice it when you are in your shed. You’ll have a drip here or there, or a noticeable stain on the sheathing when you look up.

A damaged underlayment can often be fixed just by fixing the hole or ripped shingle or another outer layer of roofing material. This usually doesn’t require an entire teardown of the roof. If the leak has occurred over a long time, then you may also have to replace the sheathing beneath – see below.

Roof Sheathing or Plywood Repair

Whether you’ve used typical OSB roof sheathing or plywood, you don’t want either to be exposed to moisture. A hole in your roofing material, or a leak at the edge of a roof vent, will damage sheathing beneath, but not always to the point of replacement.

Both sheathing and plywood can withstand some moisture penetration before needing replacement. Removing outer roofing material and underlayment from above will allow you to see the extent of the damage. If the OSB or plywood is soft, then it has to go.

Also, if there is noticeable sagging to your roof, particularly between the rafters, then your sheathing is compromised — time to replace – no inspection necessary.

If you have to replace a section of plywood, then you’ll have to remove all the material on that piece. For most sheds, this usually means removing some or most of the roof. Depending on your roofing material, it might just be easier to take off the entire roof and replace it. However, I believe in keeping costs to a minimum, so I try to avoid that at all costs!

Rafter Repair

Hopefully, it hasn’t come to this, but if you leave a leak for a long time, then not only will the OSB need replacement, your roof rafters will too. If this is the case, it isn’t always mandatory to replace the entire roof. You’ll have first to fix the sheathing, so see above.

When it comes to fixing the rafter, you might have the option of merely sistering it with the existing damaged rafter. That means cutting it to the exact dimensions of the other rafters, then affixing it, so it sits butting up against the damaged rafter. Of course, make sure the rafter is anchored to the shed – not the damaged rafter!

If you have more than one rafter that is damaged, then a teardown of the shed roof is probably in your future. Regular visual inspection of your shed roof is always a good idea – walk into your shed and look up! 

Be sure to keep an eye from above as well – you should have a close look at the top your shed at least once per season to ensure a shingle hasn’t flown off or a screw has dislodged.

Repairing Shingles on a Shed Roof 

I’d be willing to bet your shed has a shingle roof. They’re cheap, easy to install, and durable as hell. But if exposed to constant sunlight or very high winds, they can deteriorate or fail altogether. Some crack, peel, or fly away, leaving your roof sheathing exposed.

Your next question is probably: Can I replace just one shingle, or do I have to do a whole row or section? Luckily, if you have only one damaged shingle, then you can remove it and install a new one. However, most people find that more than one, and often a whole section of a shingle roof needs replacing.

So how do you replace a single or a section of shed roof shingles? Let’s have a look, step by step.

Remove the damaged shingle.

If the wind blew the shingle off, then you can affix install a new shingle underneath — no need to worry about lining up nail holes or anything like that. Just make sure your new shingle fits exactly like the last one. Nail into the tar strip and you are all set.

If you have a damaged shingle, then you’ll need to use the flat end of a crowbar to pry it up. A 24” crowbar works nicely. Alternatively, there are roofing tools such as a roof ripper or a hammer with an extended claw on the back that will also quickly pull your damaged shingle off.

Important – remove the old shingle slowly and make sure your crowbar or ripper pries the old shingle from where the existing nail is sitting. This will ensure a clean pullout, reducing the risk of the underlayment or sheathing getting more torn up.

Inspect the sheathing and underlayment.

When you have the shingle off, be sure to check underneath for any further damage. For instance, if your leak is a shingle next to a roof vent or pipe, then you should also inspect the flashing around the opening.

Shingles should cover the flashing around a vent on top and sides. The bottom of the vent flashing should be visible and above the row of shingles just beneath it. All exposed nails, as well as the edges around the vent flashing beneath the shingles, should have roof sealer.

Replace the shingle.

Once you’ve removed the damaged shingle, if necessary, and have determined that the OSB is still in decent shape – not soft or rotten – then replace your shingle. Standard 3-tab shingles are of a uniform size, so replace the shingle.

When replacing, be sure not to damage the shingles above. This is the trickiest part, as the shingle above the damaged shingle will need to have its bottom row of nails removed so the new shingle can slide under. Use a flat pry bar or roof ripper to lift each nail gently. Pull the nail up with your fingers.

When reinstalling the new shingle, make sure you re-insert the nails through the original holes to ensure the shingle above does not begin to leak.

How to Repair Metal Shed Roof

If you have a metal shed roof, then consider yourself lucky – metal lasts forever and is far more unlikely to fly off in a storm – unless you live in Kansas! With that being said, your shed metal roof can fail. Often it’s a leaky screw hole or improperly seated sections of roofing.

Here’s a quick overview of how to fix a metal roof on a shed.

Leaking Screw Holes

Metal roofing is impervious. Except that it relies on hex head screws with thick rubber washers. Sometimes these washers fail, hardening and wearing away in extreme sun or cold. When this happens, water can seep under the metal roofing.

Fixing this type of leak is as simple as replacing the screw. Coating the screw hole with a metal roof sealer will ensure the screw will no longer be an issue. It dispenses from a tube just like a tube of silicone or acrylic.

Metal Roof Rust

Over time a metal roof is prone to rust. A new steel roof is most likely galvanized, meaning it has a zinc coating over the top. However, scratches from tree branches or other impacts will expose the steel underneath, leading to rust.

If the rust is really bad, then you’ll have holes and it’s time to replace one or more of your roofing panels. This is as straightforward as removing your old metal roofing panel and installing a new one. Be sure to use new roofing screws, since the rubber washers on the old panel are probably hard and deteriorating.

You can also paint a metal roof. It is recommended that you repaint it every ten years or so. Why? It’s another covering that protects the roof. Before you apply paint, you will want to apply a coat of metal roof sealant which comes in a can and is applied with a brush, roller, or sprayer.

Regular sealing and painting will keep the rust away for much longer than not painting at all.

Corrosion on a Metal Roof

Metal roof corrosion is an issue if you have used other types of metals in conjunction with your steel roof. For instance, aluminum flashing or drip edge around the edge of your roof may corrode the steel faster than galvanized steel flashing.

More importantly, you mustn’t use treated wood for your rafters. Treated wood has copper in it, which will corrode galvanized steel. Left unchecked, your steel roof will corrode wherever it is making contact with the rafters, causing the entire roofing material to either blow away or fall inward.

Lastly, if you are thinking about installing roof vents or solar panels, be sure your fasteners are of the same type of metal as the roof. This is the only way to ensure your roof doesn’t corrode – avoid mixing and matching metals.

Improper Installation

All metal roofs come with specific installation instructions. Failure to follow directions will result in a leak every time.

The first thing to understand about installation is that driving the roof screws requires caution. You want the rubber washer to seat snugly, but not to be too compressed. If you drive a screw too far, the washer will break and allow water to get through, causing a leak in your shed.

Remember – metal roof silicone sealant is your best friend. Every panel should be sealed with a 100% silicone product. All vent openings should also be sealed. Screw holes do not need to be sealed.

How to Repair Shed Roof Felt

Asphalt roofing felt is an extremely cheap and durable option for your shed. If you have it, you already know how easy it is to install. However, you do get what you pay for in terms of durability.

The thickness of asphalt felt lends itself to leaks or damage from storm debris. Let’s have a look at how to fix asphalt roofing felt issues.

Tears, Rips, and Other Penetrations

Fixing roofing felt is not difficult, but you want to purchase the right product for the job. If you have a hole, then using a product like this will get the job done.

If you have rips or a tear, a product like this works pretty well. You’ll still need to use the roof patch compound with the fabric, but this will cover most holes or rips.

In the event of high wind or some other catastrophic event, you can replace an entire row or the whole roof if necessary. Remember, you chose roofing felt because it is cost-effective, so any replacement isn’t going to break your wallet.

Other Roofing Felt Leaks

If you keep having to patch your roofing felt on the shed, then you might need to start thinking about covering up your felt altogether.

Adding a layer of shingles isn’t going to be expensive unless you have a big shed. Keep in mind that even the best, heaviest rated felt doesn’t have nearly the lifespan. If you’ve had more than a leak or two in your felt, cover it up with shingles.

Fixing a Wood Shake or Shingle Shed Roof

Wood is beautiful. However, that beauty comes at a cost. If you’ve lost some wood shakes or shingles from your shed, then you are going to have some work ahead of you. Unlike standard asphalt shingles, wood shingles and shakes don’t bend.

Here’s how to fix a shingle on the wood roof of your shed:

  1. Remove the broken shingle. Use a hammer and chisel or flat head screwdriver to break up the shingle. Carefully pull out the broken pieces of the shingle. Careful not to damage the shingles around the damaged one.
  2. You’ve got to get the old nails out that held the damaged shingle in place. A shingle ripper is a marvelous tool for this purpose – if you have a wood shingle roof, then investing in this tool is a good idea. Slide the ripper up under where nails are, then use a hammer and swing down on the ripper handle edge. This will cut the nails off at their base.
  3. Once you’ve removed the nails, you can install your new shingle. Remember, a wood shingle needs about a quarter inch on each side to account for expansion and contraction, so measure carefully.
  4. Install the new shingle, slide it up under the shingles above. Slide it until it is just about ½” below the other shingles in the row. Then, place your nail at a 45-degree angle so that it buts up against the edge of the shingle above the one you are installing. Nail it at that angle. Do this for both nails.
  5. Lastly, use your hammer to gently hammer the shingle up the last ½” into place. That way the angled nails you just hammered are covered by the shingle above. Make sure you use stainless or galvanized nails only!

Other issues with wood shingles are mold, rot, mildew, and moss. Regular coatings with wood treatment will mitigate many of these problems. However, if you have significant moss or mildew buildup, you will need to call a professional to pressure wash your roof with special fungal compounds.

If you find that after treatment and cleaning that your wood roof is still mildewing quickly, then remove trees and other obstacles that might be impeding the sun. A constantly wet roof will mildew any wood roof, no matter how well you take care of it.

 

How to Replace Shed Roof Plywood

Replacing the plywood or OSB roof sheathing on your roof will require you to remove most, if not all, of your roofing material and underlay. However, if you are already removing much of your roofing material for replacement, then changing out the plywood is not much more trouble.

If you have a leak, and you’ve noticed it, then chances are it has seeped onto – and into – your roof sheathing. A leak that causes visible stains to the undersides of your sheathing – visible from within the shed will need to be replaced.

When replacing the plywood, be sure to remove all the old nails or screws. If you are replacing plywood, then do a thorough visual inspection of the rafters as well. Plywood replacement is also a great time to sister or replace your shed rafters.

When installing the new plywood, be sure you’ve chosen the same thickness of sheathing if you are only repairing one section of plywood. Also, take into consideration your new roofing material, if necessary. Wood shingle roofing requires entirely different sheathing than other types of roofing.

How to Repair Sagging Roof

A sagging roof can mean any number of things: sagging rafters, improperly constructed roof, walls not appropriately built, etc. First, check to make sure your roof was correctly built if you were not the builder. Look inside your shed. Are there ceiling or roof joists? Are there webs or collars further reinforcing the roof? If you answer no to all of these, then you have larger, structural problems that require a roof replacement.

If your roof seems properly constructed, and the walls of your shed aren’t bowed outward (or inward!), then you are in luck. It is likely that you can get by just replacing the sheathing or rafters of your shed.

To replace your rafters and sheathing, whether OSB or plywood, see above. Understand that sagging in a roof, when not a structural problem, is always going to be either the sheathing or rafters. Simply adding a different or extra, a layer of roofing material will only make the sagging worse – avoid!

Repairing Other Types of Shed Roof

Other types of shed roof materials have their issues – let’s take a quick look at roofing material alternatives and the types of repairs you will encounter with each.

Rubber Repair

Fixing a rubber roof is as simple as buying a can – or bucket – of a rubberized cement sealer like this. These compounds are designed to be used with either a section of rubber roofing, for larger holes or by itself for smaller holes.

Remember that rubber roofs are incredibly durable. In some cases, they can last for over 50 years. However, if you have to use rubber roofing cement, know that regular inspection of the patch is essential. The cement will break down before the rubber, and you’ll have to reapply before you replace your rubber roof.

Often rubber sealers can be painted. This is always advisable because the paint acts as an added barrier to scratches and UV damage.

Polycarbonate Repair

One of the most common issues with polycarbonate or plastic roofing is that people mistakenly use silicone with the plastic panels. This is a big-time mistake. Polycarbonate roofing expands and contracts. It needs room to move. The silicone used in large doses, such as to seal panel edges, will restrict this movement.

If that happens, panels will crack either at the screw holes are along the seams where silicone was applied. You will have to remove all the panels where the sealant was used and replace.

Also, polycarbonate panels require using flashing products designed for use with the roofing material. Do not mix and match materials. This can lead to leaks around the edges or will break the roofing material altogether.

If you get a small hole in the plastic, using silicone is fine. You don’t want to use it to connect two pieces of polycarbonate. Also, removing polycarbonate panels to clean out the spaces where the panels overlap is a good idea. If the panels don’t mesh properly, water can eventually work its way down and back up and into your shed.

Conclusion

A roof leak isn’t the end of the world. With the right materials and help from this article, you should be able to take care of pretty much any leak that comes your way.

Remember, inspecting your roof regularly, such as once a season, is the best way to avoid leaks and time-consuming damage to your shed.

I hope you found this article helpful and that you were able to use it to help you fix your shed. As always, feel free to share this article if you liked it.

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