We hate to say it, but summer is winding down. Before we know it, it will be fall – an important time for roof care. Flat and low-sloped roofs require special attention if you want them to be prepared for the colder winter months.
Inspect your roof for any damage, such as blisters or cracks, and repair them immediately. Renewing coating is necessary every two to four years unless the roof is also covered with a layer of gravel. If so, keep the gravel spread over the entire surface and add more if any is lost.
Repairing blisters eight inches or less is relatively simple, but a professional roofer should repair larger ones or inspect a roof with many blisters. Start by sweeping off the area and make an X-shaped slit in the roofing, one layer at a time, with a utility knife.
Should the blister contain moisture, stand on it to squeeze out as much water as you can, and prop the flaps open to let the area dry. If you can find the source of the moisture, try to repair it – the reason is often cracked or torn roofing or parapet flashing. If you don’t fix it, the problem will persist and may cause severe damage.
Once the area is dry, spread plastic or asphalt roofing cement beneath the flaps and press them flat with a putty knife. Spread additional cement over the repair and press a piece of asphalt-saturated cotton patching into it. Finish it by spreading a layer of cement at least an eighth of an inch thick over the fabric and several inches beyond it, and smooth it out so there are no ridges to collect water.
If opening a blister on a roof reveals rust, use a wire brush to scour the area and once it is dry, apply rust-inhibiting primer. Repair the area once it dries. If the rusting is severe, have a licensed roofer inspect your roof.
Spread roofing cement over cracks to repair, embed fabric in the cement and cover it with more cement. If felts are torn, cut out a square or rectangle around the spot with a utility knife, cutting as deeply as the damaged layer. Make a patch of 15-pound or heavier roofing felt thick enough to fill the area, and cement the patch into place. Finish as if repairing a blister.
If you have parapet flashing that needs to be patched, first pry up the metal cap protecting the ridge and spread roofing cement over the damaged area. Then cover it with a layer of new flashing material that goes three inches beyond the damage on all sides. Position the top edge of the new flashing so the metal cap will be able to cover it when reinstalled. Cement a larger piece of new flashing over the first, cover it with the cement and reinstall the cap.
When applying coating, do so in dry weather when the temperature is between 65 and 75 degrees. Higher temperatures soften roofing, and walking on it can cause damage. Make repairs first if necessary then sweep the roof free of debris. Stir the coating thoroughly and begin spreading it with a brush at a point farthest from the ladder so you will be able to get off the roof when finished. Spread the coating about an eighth of an inch thick or as otherwise directed. Discard the brush when finished, and store the unused coating, closed tightly in an area where it won’t freeze – it can be stored for up to three years.
Courtesy of The New York Times