Articles » DIY - How to Inspect and Repair Roof Flashing on Your Own

DIY - How to Inspect and Repair Roof Flashing on Your Own

Tags: Roofing, Inspection, Repair

Here is another installment to our roofing Do It Yourself (DIY) series. This time we discuss ways to repair a damaged roof flashing on your own:

Is your ceiling bulging or sporting ugly stains? Is water dripping onto your floor? It's easy to know when you have a leak, but locating the source of the problem might be a bit more difficult. Once you've ruled out a leaking toilet or overflowing bathtub, it's time to suspect your roof.

Head up to the attic or crawl space, position yourself in the general vicinity of the problem area and look for a wet spot in the roof. Although the leak itself is probably not in that exact location, the most likely culprit is the flashing closest to the problem area.

Flashing is made of aluminum or galvanized steel, and its purpose is to cover certain construction areas to keep them from leaking. On the roof, you will ordinarily find it in such areas as the valleys, the vents and the chimney. When flashing fails, it is normally because it has oxidized or, for some reason, come loose.

Replacement may not be necessary. You can plug pinholes with roofing cement, and holes up to ¾ inch respond well to patching. Clean the area and roughen with a wire brush, then cement into place a patch of the same material and cover with additional roofing cement.

Chimney Flashing

The chimney is a common site for roof leaks, but the flashing may not be the problem. First, check the condition of the chimney itself. A damaged chimney can allow water to run under the flashing and, from there, through the roof. If this is the case, you'll have to repair the chimney.

If chimney repair does not solve the problem, check the chimney's cap flashing. If it has come loose, pull it gently away from the chimney and reattach with roofing cement. If the chimney's base flashing needs replacing, lift the surrounding shingles and cement new chimney base flashing underneath. Seal all seams with roofing cement or silicone caulk.

Head Wall Flashing

If you've traced the leak to where the roof butts up against a vertical wall, you could have a problem with the head wall flashing. These repairs will entail dealing with the siding material on the adjoining wall as well as with the roofing material.

Lift the surrounding siding and roofing material gently away from the structure. Cut a piece of replacement flashing larger than you think necessary, apply roofing cement and slide the flashing under the roofing and siding. Chip out any old mortar and use masonry caulk to seal any joints. Use urethane roofing cement or silicone caulk to seal the seams.

Vent Flashing

Roof leaks are often traceable to plumbing, attic, furnace or air-conditioning vents. Before replacing the flashing, remove the roof shingles that cover the flange, then pry off the old flashing and remove nails. Push a new piece of vent pipe flashing into place and nail it near the edges. Replace all shingles, and cover all nail heads with roofing cement.

Roof Valleys

When roof valley flashing fails, some of the water might not make it all the way down to the gutter. To replace, gently pry up the surrounding shingles and spread roofing cement about six inches underneath. Slide the new flashing into place under the shingles.

In General

When patching flashing, make certain that your patches are composed of the same material as that found in the original flashing. If replacement is necessary, be sure to get the right kind of flashing for the area under repair.

Fortunately, repairing roof flashing is more dangerous than difficult. If you have a fear of heights, however, it might be prudent to have your roof repaired by a qualified roofing company.

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