Limitations and Disadvantages of flat roofing:
Flat roofs have a number of disadvantages. The main issue is the fact that there is no slope and all the water/snow sits on the roof. While water can be taken care of with proper drainage, snow will sit on the roof until it melts. All this moisture and sun drying it causes cracking. Another disadvantage that haunted flat roof installs for over 50 years is pooling water. Until the invention of rubber membranes such as an IB roof, there was no effective and cost effective way to eliminate the leaks caused by pooling water. Creating a slight pitch and multiple drains was required, and still pooling water caused over 75% of all flat roof leaks.
Benefits of flat roofing construction:
Flat roofs also have a big misconception among many home-improvement contractors and residential builders / architects that flat roofs = problems. This roof isn’t the “norm”.
The truth is that flat roofs are very convenient, easier to build, and cost less than a pitched roof. Building a reliable pitched roof in those cases will require extra design to accommodate for additional weight.
When you compare all the construction costs and environmental benefits, flat roofs can sometimes surpass any sloped roof. These asphalt shingles end up in our landfills every 12-15 years, and yet more and more of them are produced.