How to Patch a Flat or Low-Pitched Roof
Flat-roof patches are temporary fixes. You should plan to replace them with a permanent repair as soon as is practical, unless you'll be reroofing in the next year or so.
- Difficulty:
- Moderately challenging
Instructions
Things You'll Need
- Fiberglass Reinforcing Cloth
- Plastic Roof Cement
- Cloth
- Window Cleaner
- Brush
- Disposable Trowel Or Wide Putty Knife
- White Gas Or Splicecleaning Fluid
- Utility Knife
- Caulking Gun
- Butyl or polyurethane sealant, or peel-and-stick roofing tape
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1
Brush aside the existing gravel (in a built-up roofing system) and scrape off any that remains in the area you're patching. For double-coverage roll-roof systems without gravel, just brush and/or blow off dirt, loose materials and dust.
- 2
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3
Immediately embed a layer of fiberglass cloth into the cement, pressing it lightly with the trowel or wide putty knife.
- 4
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5
Allow the patch to dry and preferably withstand the test of another rainstorm before you cover it with gravel.
Repairing in the rain
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1
In the case of sudden damage--caused by, say, a fallen tree limb or a storm that blows loose an object anchored to the roof--make an immediate repair, even in the rain, to limit interior damage. Use a roof cement formulated for application on a wet roof.
Repairing a rubber roof
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1
Clean the damaged area with window cleaner, then wipe it using a cloth dampened with white gas or splice-cleaning fluid (available from a roofing supplier).
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2
Cut the tip off a caulking gun and use it to apply butyl or polyurethane sealant to the tear or hole, then smooth the sealant with a trowel. Alternatively, use a peel-and-stick roofing tape and apply weight to press it firmly into place.
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1
Tips & Warnings
Never make a repair if there is any danger of lightning.
Walk and work carefully on a built-up roof to avoid damaging it.
Protect your hands with rubber gloves when cleaning a rubber roof or work gloves when installing a roof patch.