How to Extend a Gable End Roof Overhang

Co-authored by Eric McClure

Last Updated: October 21, 2021 References

A gable roof refers to any pitched roof that meets in the center of the building to give it a triangular look. Gable roofs are excellent at keeping water away from the building when it rain since the natural angle makes it hard for the water to build up. Unfortunately, if your overhang is too short, the water may slide down the side of the building when it rains—even if you have a gutter installed—which can lead to foundation damage and erosion over time. Extending a gable roof can be tricky since it involves working on the roof, but you may be able to do it yourself if you only need to add ¹⁄₂–2 inches (1.3–5.1 cm). However, for larger extensions you’ll need to hire a professional to get up there and remove large portions of the roof before extending the overhang.

Method 1

Method 1 of 2:

Adding Flashing

1
Look up your local building codes to see if you need a work permit. This project is a little ambiguous as far as most local laws are concerned. Some local laws will require you to get a permit to work on your roof’s exterior, while others will not. Look up your local building code and contact your local government to see if you can add flashing to a roof without a permit or if you can take a permit out yourself. In some areas, you’ll be required to hire a contractor for this kind of work.^{[1]
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- Building permits and codes are often published online. They’re formatted differently by each city or county. Look for the section about roofing or exterior work.
- Adding flashing will give you an additional ¹⁄₂–2 inches (1.3–5.1 cm). It won’t extend your roof by much, but this is more than enough if the water is barely missing the gutters or you just need to make a minor correction.
Warning: This is really not a good idea if your roof is more than 1 story off of the ground. Since working from a ladder can be kind of tricky, you’re better off hiring a contractor to do this if it’s a 2-story building or bigger.
2
Purchase enough drip-edge flashing to cover the overhang. You can measure the overhang’s edge if you’d like, but it should be pretty easy to make an educated guess just by doubling the length of the wall underneath the roof. Head to your local construction supply store and purchase enough flashing to cover the sides of your overhang.^{[2]
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- Drip-edge flashing is roughly $1-2 per 1 foot (30 cm). It shouldn’t cost a lot to get enough for your overhang.
- Drip-edge flashing is also known as drip-cap flashing. It’s usually used to insulate shingles from water, but there’s nothing wrong with using it to extend an overhang a little. It’s basically an L-shaped sheet of aluminum that will rest on the edge of the roof and send water away.
- It’s best to have some flashing left over in the event that you miscut a piece.
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3
Rent some scaffolding or get a heavy duty ladder to stay safe. Since you’re going to be working on the roof, it’s important to have a strong, stable platform to work from. Either rent some scaffolding from a local company or get a reinforced ladder and enlist a friend to hold it for you while you work.^{[3]
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- It will typically cost $20-150 a day to rent scaffolding depending on the type of scaffolding you choose.
- Again, this really isn’t safe if you’re working on anything above 1 story. Hire a contractor to do this for you if your overhang is more than 15 feet (4.6 m) off of the ground.
4
Cut the flashing into 3–4 ft (0.91–1.22 m) sheets using tin snips. Tin flashing typically comes in 6–8 ft (1.8–2.4 m) sheets. To make the flashing easier to work with on your roof, use tin snips to cut the pieces into 3–4 ft (0.91–1.22 m) portions. Throw on some thick gloves and cut perpendicular through the length of each piece of flashing to make the pieces more manageable.^{[4]
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- Keep your cuts as straight as possible. When you put two pieces together, you’ll have trouble fitting the pieces if the cuts aren’t straight. You can fill in gaps with caulk or roofing cement if this happens, though.
5
Slide your first sheet of flashing under the first layer of shingles. Get up on your roof or scaffolding. Take the longer, flat side of the flashing and gently slide it in between the first row of shingles and the roof. Slide the flashing in and line it up so that the bent angle runs parallel to the overhang.^{[5]
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- You can either slide the flashing in all the way so that the bottom of the L-shaped aluminum is flush with the overhang, or leave a 1–2 in (2.5–5.1 cm) gap between the back of the flashing and the side of the overhang.
- Keep the bent lip side pointing down when you’re installing the flashing. Orient the small angled edge on the bottom of the L-shaped sheet away from your home.
- You may need to pry the shingles up a little with a flathead screwdriver or putty knife if a heavy-duty adhesive was used to install them. There’s usually a little give and flashing is extremely thin, so this shouldn’t be a problem.
6
Place 1 nail every 1–2 ft (0.30–0.61 m) to fix the flashing to the roof. You can do this with a nail and hammer, but it’ll be easier to use a nail gun. Use 2–3 in (5.1–7.6 cm) roofing nails and drive a nail into the shingle, through the flashing, and into the roof underneath.^{[6]
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- The flashing is really thin, but shingles can be relatively thick. Choose the size of your roofing nails based on the thickness of your shingles. The nails must be at least twice as long as the thickness of the shingles.
7
Cover the head of each roofing nail with roofing cement. Grab a small container of roofing cement and throw on some nitrile gloves. Use a putty knife to scoop up a small dollop of roofing cement and place it directly on top of the first nail. Spread the cement around with the edge of your putty knife. The roofing cement will keep water from sneaking in through the edges of the nail over time. Repeat this process for each nail you used to attach the flashing.^{[7]
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8
Continue working your way around the overhang until it’s fully extended. Move your scaffolding or ladder to the area adjacent to the first piece you’ve installed. Repeat the process by sliding your second sheet of flashing under the shingles. Line the edges of the first piece up with the edges of your second piece before nailing and patching it into place. Continue doing this until you’ve fully extended the overhang.^{[8]
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- When you reach a corner, simply measure the distance from the end of the corner to your last sheet and cut the flashing to size. Thinner flashing can typically be bent by hand if you need to go around the peak of an angled roof. Just be sure to wear thick gloves if you do this!
- You do not need to extend the entire roof if only one side or area is problematic. It may look better if you do the entire roof, but it may not matter if it’s on the side or back of your building.

Method 2

Method 2 of 2:

Hiring a Contractor to Extend the Roof

1
Look online to find reputable roofing contractors to extend the roof. Search online to find roofing contractors or companies in your area. Look up independent reviews to see if they’re reputable. Check out the company websites to find out if they’re insured and permitted to work in your area. Compile a list of 4-5 reputable contractors to contact and get quotes.^{[9]
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Warning: Extending a roof is not realistically something you can do on your own, even if you’re an experienced woodworker or builder. You need a contractor that is capable of pulling the permits and has insurance to do this work for you. Apart from being illegal in most areas, this process involves removing a portion of a roof and rebuilding it. If it isn’t done by a professional, you could end up with a leaky or collapsing roof.
2
Call multiple contractors to get quotes for your project. The cost of this project will vary from contractor to contractor. Most roofing companies will provide quotes for a project free of charge. Call each of the contractors on your list to see what they’ll charge to extend your overhang. Depending on the size of the building and the scope of the project, this may cost anywhere from $50-350 per foot of overhang.^{[10]
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3
Get additional rafters installed to extend the overhang by more than 10 inches (25 cm). If you’re trying to add more than 10 inches (25 cm) to your roof, you’ll need to have the contractor install additional rafters to manage the additional weight of the materials. The contractor will remove the drywall and shingles before nailing additional rafters against the old rafters. This way, the new rafters will be supported by the old rafters and you won’t need to worry about the roof collapsing.^{[11]
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- This option tends to cost more than just adding a short amount to the existing rafters, but it’s the only way to safely extend the overhang by more than 10 inches (25 cm).
- You do not need more than 2 feet (0.61 m) of total overhang for your building to stay safe and avoid water damage. If you only have 1–2 inches (2.5–5.1 cm) of overhang, you likely need to go with this option.
4
Choose to extend the preexisting rafters to add 2–9 inches (5.1–22.9 cm). For minor additions, the contractor can remove the side of the roof and attach additional pieces of wood to the preexisting rafters before refinishing the roof. The extensions won’t hold much weight, but this is a fine choice if you’re only adding 2–9 inches (5.1–22.9 cm) to the overhang.^{[12]
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- Most buildings are designed with reasonable overhangs to begin with, so this is the best choice if you already have plenty of overhang extending past your roof.
5
Pay the contractor once you’ve found a price you’re happy with. Once you find a reasonable quote from a reputable contractor, pay the upfront material costs and wait for them to fill out the necessary permits. Once all of the paperwork is filed, the contractor will bring a crew out and get to work on your overhang.^{[13]
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- The price for this work really varies. For a short extension on a smaller building, it may only cost $1,000-1,500. For larger, complicated projects, this may run you $5,000-15,000. It really depends on the size of the building, the shape of the attic, the height of overhang, and whether you’re extending the rafters or installing new ones.
6
Get out of the building to give the work crew space to work if possible. If you can, get out for the week or so that the crew is working. The contractor’s crew will be removing large portions of your attic and roof. They’ll also be hauling lumber up the stairs, cutting the lumber, and nailing it into place. Expect to deal with some loud banging and heavy disruption if you’re sticking around while they work.^{[14]
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- Start the work on a Monday when you know you’re going to be out for work if you’re extending the overhang on your home.
7
Wait a week or so for the work to be completed. The crew will start by removing the drywall in your attic, to access the rafters. They’ll also need to remove the shingles and siding on the roof. Then, they’ll either add the extensions or install the new rafters depending on what you chose. Once the overhang is extended, they’ll reinstall the drywall, and refinish the roof to give you the coverage you need.^{[15]
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- If your building is really big, this project may take 2 weeks or more. Contractors typically bring a pretty big crew for this though, so it won’t typically take this long.
- When the work crew is done, your overhang should look basically the same as it did before except it will extend further away from the building. The newer materials may clash a little with the rest of the building, but it should blend in pretty seamlessly over time.

Warnings

Do not attempt to install rafters yourself. Not only is it probably illegal, but you’re risking the structural integrity of your building if you don’t complete the work perfectly.^{[16]
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