Flat roofs aren’t very different in shape from slope roofs, but they are less efficient. They do drain but not as well as a sloped roof would. Be it rain, hail or other debris, it slides off much easily on a sloped roof and therefore does not cause much damage.
Usually, water puddles remain on a flat roof, which compromises the roofing material and might lead to water leakages. This is one reason why waterproofing your roof is so important. If you live in an area where the weather isn’t gentle, or rain or snowfall is frequent, choosing a sloping roof over a flat one would be a better option.
When it comes to flat roofs and choosing a roofing material, you are limited to a few options. More often than not, they have some issues and the life span of these roof materials isn’t exactly spectacular.
BURs are inherently heavy, so you might need to get the joists strengthened. Also, as gravel clogs gutters it might be difficult to locate the source of a leak. MRB is a type of roofing material that employs a torch-down system during installation and it can in some cases be considered as a fire hazard.
Finally, EPDM is considered to be a fairly good material but is relatively expensive. You may pay extra if you decide to go with light-coloured coatings. Considering most people choose to go with flat roofs because they are more affordable, paying extra doesn’t advocate the case for flat roofs.