Do flat roofs always leak?
Monday, October 4, 2021
Not true. But it may seem like that to a frustrated homeowner with an older flat (low-slope) roof. Here’s three reasons why:
1) Flat roofs leak more water when the roof begins to fail - A sloped roof only has to resist water briefly as it rolls over the surface and heads quickly downhill. Although roofs that are called flat all have a slight slope for drainage, low spots develop over time where water puddles until it evaporates. Because leaves tend to collect in the low spots and add acidity to the standing water, this hastens roof deterioration. And these are often the first places to leak, with the water continuing to drip through even a tiny opening until the puddle has drained. So flat roof leaks tend to be more dramatic.
2) Flat roofs typically don’t last as long as sloped roofs - Several common flat roof materials have a shorter average lifespan than their sloped roof counterparts. The 3-tab shingles at the left in the picture above have a 20-year average life, while the modified bitumen flat roof is rated at only 15-years—making it likely to fail first.
3) Installing a flat roof requires more skill and experience to do correctly than a sloped shingle roof - So a sloppy installation of a flat roof is more likely to leak.
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Here’s links to some of our other articles about “FLAT ROOFS (LOW SLOPE)":
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