How To Make Basic Roofing Repairs

by Josh on September 19, 2011 · 0 comments

in Outdoors,Projects

Homeowners who neglect the condition of their roof do so at their peril. After all, water will always take the path of least resistance– and with damaged shingles that could be through your ceiling or walls. Knowing how to make a few basic repairs to your roof can not only save you the cost of hiring a roofer or handyperson, it can save you the headache and cost of repairing interior water damage.

First, a warning: Put your personal safety first whenever using a ladder or working at height. Don’t work around power lines, antennas or when inclement weather is possible. If you feel uncertain about the steepness of your roof or the safety of your work area, don’t risk your health: call a professional.

If you can safely access your roof, here are a couple of simple repairs that can help keep your home dry and secure.

damaged shingle

Replace a Damaged Shingle

Shingles are designed to shed water over a series of overlapping layers of roofing from peak to gutter. However, if a shingle is damaged, water can flow underneath the lower shingle courses, through the roof deck to the insulation, ceilings and walls, according to Roof Co. They fixed my roof in Winnipeg so I’ve relied on their advice ever since. Fortunately, replacing a shingle isn’t hard if you work carefully.

removing damaged shingle

Begin by loosening the damaged shingle from the course below it with a flat pry bar, breaking the tar seal that helps hold the installed shingles together. It’s best to do this on a warm day after the sun has heated up the roof a bit. If the roof is too cold, the shingles will be brittle and susceptible to cracking; too hot and your footsteps can damage the soft shingles. Remember, a three-tab shingle has–you guessed it– three tabs that all need to be loosened in order for the shingle to be removed, even if only one of the tabs is damaged.

pulling roofing nail with prybar

With the necessary shingle tabs loosened, remove the roofing nails from the damaged shingle with the end of the prybar. You will likely need to remove nails from the damaged shingle and the shingle course above it to remove the damaged roofing. Once all the necessary nails have been removed, the broken shingle should slide out easily.

damaged shingle comes out

If a cut in the replacement shingle is necessary, like in this open valley on my roof, try to use the damaged shingle as a cutting template.

scoring shingle cut

In the photo above, I have lined up the old shingle on top of the new and am using the edge of the old shingle to score a cut line with my razor knife. Be careful when cutting on top of the roof so you don’t damage installed shingles with your knife. Using the backside of an old shingle as a cutting board is a good way to protect your roof from damage when making cuts.

new shingle cut to size

With the replacement shingle cut to size, position it on the roof and nail it in place to complete the repair.

nailing in replacement shingle

Use care when hammering to avoid accidentally damaging nearby shingles. For a small job like this, it may be tempting to cut corners on the hardware. Don’t do it. Use galvanized roofing nails that won’t corrode and stain your roof and that have a wide flat head to resist tear-out. I picked up the nails I needed at my local True Value Hardware. I was fortunate to have a bundle of extra shingles left by the previous owners in my storage crawlspace.

shingle color comparison

Other than the slight color difference between the new replacement shingle and the sun-faded roof, the completed repair is seamless and ready for rain.

Sealing Valley Flashing

Recently the open roof valley (different from the one in the photos above) that ends over my front porch has started leaking during moderate or heavy rains. There hasn’t been any permanent damage to the porch because of this, but I want to stop the leak before it becomes a bigger problem.

The first step to diagnosing the source of a leak is to look for obvious damage to the flashing or shingles– like the repair I showed above. In this case, both the shingles and flashing looked fine so I decided on a blunt but straightforward repair: roof cement.

roof cement

Without obvious roof damage to point to, I suspect that water may be getting under the shingles where they overlap the valley flashing. Roofing cement can seal that transition and prevent water from getting through. Roofing cement comes in tubes like caulk, is applied like caulk, and works like caulk, so this is also roofing job any DIYer can handle. It’s inexpensive, too– the three tubes of Black Jack I used for this job cost less than $10 at True Value.

applying roof cement at valley

To seal the valley flashing, start by loading the roofing cement in a caulk gun and taking a large cut off the end of the nozzle so that it will leave a thick bead of sealant. Because of the overlap of shingles from bottom to top, it is easiest to start at the eave and work up to the peak.

roof cement overfill

In a few spots, I used a bit too much roof cement or got the bead too close to the edge of the shingle, resulting in overfill/squeezeout. Although I’m not thrilled with the aesthetics of this mistake, it should still perform fine. It can take a bit of trial and error to synchronize pulling the trigger and aiming the nozzle, so take it slow and steady.

Since making this repair to the porch roof, I haven’t seen the leak return. For thoroughness, I am going to dab a bit of roof cement between the overlapping shingles at the valley, too, so the roof is ready for the stress of another long Minnesota winter.


Now is a great time to make sure your roof is ready for winter precipitation. If you are able to safely inspect your roof for damage, simple roofing repairs can be inexpensive and straightforward DIY house projects.

Got a roof over your head? Share your roofing questions, tips and tricks in the comments.

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