This guide covers the basics of flat roof repair, also known as low-slope roof repair, including:
- Locating the leak
- Repairing flat roofing
- Knowing when replacing the roof is a better option
- The cost of flat roof repair and replacement
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If your home or building has a flat roof, then you know that water is its major nemesis and leaks must be aggressively addressed with top-quality flat roof repair materials and methods. We explore whether DIY flat roof repair is something you want to attempt or if it makes more sense to hire a professional flat roofing specialist.
These flat roof repair techniques can be used on the most common flat roof materials:
- EPDM, aka Rubber
- Modified bitumen
- BUR (Built up roofing), aka tar and gravel
Note: If you happen to have a PVC or TPO roof leak, such as a leaky seam or a hole/puncture caused by a fallen tree branch or an accidental cut, then you will need to find a qualified specialist equipped with all the necessary tools and supplies; a roll of appropriate membrane and a heat air gun. Look for a company specializing in PVC or TPO.
Locating a Flat Roof Leak
While finding a leak in a flat roof is easier than on a steep-sloped, shingled roof, leaks can still be deceiving. Where water enters your interior space might not be exactly where the leak is, because any water that penetrates a roofing membrane can travel for some distance until it finds a seam in the sub-roof or sheathing and seeps inside.
These steps will allow you to isolate the source of the leak, if it isn’t readily evident when you inspect the roof.
- From inside, measure the distance from where the leak is visible to the two nearest walls.
- Use those measurements on the rooftop to create a starting point for your search.
- Most flat roofs are very slightly sloped to facilitate runoff, so explore from the point of the water’s entrance up the slope, since water runs downhill.
- Look for punctures, popping screws, rips, worn spots, seam separations, blisters and other imperfections in the membrane.
- If no damage is found in the membrane, examine nearby vent pipe boots, flashing, caulk around vents and similar structures for damage.
- When you still cannot locate the leak, call a professional flat roof contractor for assistance and repair.
Caution: It’s always smart to respect ladders and heights, so proceed with extreme care! If you can’t access the roof from inside, use a quality ladder rated for more than your weight, and have a strong adult hold the ladder steady for you. If the roof is icy, even greater precaution is required, or a pro should be called in.
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Repairing a Minor Flat Roof Issue
Warranties for flat roofs can range from 5 to 20 years. If your roof is under warranty, call the contractor that installed it to make the repair. Even if the warranty is prorated for the age of the roof, you might still save money with pro repair. You’ll have the confidence the job was done correctly and have recourse if it wasn’t.
If the warranty is up, then you can attempt the repair yourself. If it holds, you’ve saved money; If not, you won’t make it worse with the methods we suggest, and a flat roof contractor can repair it.
Rubber Roof Repair Tools:
- Roofing Seams Probing tool
- Roofing Hand Roller tool
- Roofing Membrane Cleaner
- EPDM rubber glue
- EPDM peel and stick roofing tape
- Appropriate Ladder with ladder stabilizer
- Paint brush used to spread the glue
- Bucket of warm water and clean towels
Other tools you may need will depend on the roofing system in question and a specific problem you’re repairing. The common tools used for repairs include a utility knife ($3-$6), tube of roofing sealant or cement ($4-$6), a caulk gun ($5-$20), a 2” putty knife or brush ($1-$4) and peel & stick flashing ($35-$125/size of the roll).
EPDM repairs require a few specialty items including EPDM glue ($12/tube or $40/gallon), weathered membrane cleaner for older roofs ($12/quart or $25/gallon) and EPDM/TPO primer ($15/quart or $40/gallon).
EPDM Rubber Roof Repair Kit
Did you know? Rather than trying to get all of the above items individually, you can save a lot of time by getting an all inclusive Rubber Roof Repair Kit here