If you have a tar and gravel flat roof, you have to be on guard for roof leaks. A leak in a flat roof is more serious since the rain won't roll to the side as fast as it does on a sloped roof. When the roof is covered with gravel, it's often difficult to tell the condition of the roof underneath. One problem that can develop is blister formation. This is both a sign of a moisture problem and a leak hazard if the blister opens. Here's a look at how a roofing contractor may repair a flat roof with blister leaks.
Determine Why Your Roof Is Blistering
Blistering of a tar roof is often the result of moisture accumulation from the underside of the roof. This can happen when there isn't sufficient ventilation to keep the roof dry and to control temperature and humidity. Ways to increase ventilation on a flat roof are to add insulation and a vapor barrier or to put vents on the roof or soffit that allow air to circulate through the roof.
Check the Entire Roof
If the roofer determines that poor ventilation and moisture buildup are to blame for the blistering and leaking, they'll probably check your entire roof for blisters since the problem could be more widespread than you think. While a few blistered areas can be patched or fixed, it may be time to get a new roof rather than spend money on repairs if the entire roof is in bad shape.
Choose the Roof Repair Method
Roofing contractors don't always repair a blister that isn't leaking. The extent of roof damage and blistering is taken into consideration. The roofer might advise watching the area to see if the damage escalates and then take action. However, if the blister has split and the roof is leaking, then repair is essential.
The area to be repaired has to be cleared of gravel and then cleaned. Then, the blister material can be cut away along with the layers underneath it. This step gives the roofer a chance to inspect the deck to see if it has water damage and needs to be cut out and replaced. When it's time to patch the damaged area, the contractor will apply patch layers and seal the area with adhesive. A second patch may be applied over the first and the patch is covered with gravel.
Roof blisters can also be caused by poor drainage and moisture problems on top of the roof like happens when the debris accumulates or when water ponds in an area. Also, a flat roof can leak with or without blisters, so any time you suspect your roof has problems, it's good to call a roofer contractor to check the situation and make repairs if they're needed.