Flat roofs are popular for garage roofing. You and I both know this, because we have seen it so many times. In fact, flat roof garages are everywhere, most likely there are several in your neighborhood. So why are they so popular?
Flat roof designs have two major advantages in my view: they are both cheap and easy to build. In addition, the relatively low rise of the roof, means you are less likely to get in trouble local building codes, especially as related to how close to adjacent buildings you are allowed to build. The rules in this area are going to be different depending on where you live, but in some places the rules are so restrictive that flat roof designs are the only way you can be allowed to erect a garage in your desired location.
The reason a flat roof is cheap, is because it often uses less construction wood and less costly roofing materials generally. The classic example of a flat roof, is one that is clad with roofing felt or corrugated roofing sheets – both of which are relatively cheap roofing materials. They are also among the easiest types of roof cladding to install, which makes them ideal for the do-it-yourself person to use. Flat roof trusses are also very simple to construct, so if you put this together with easy to install roofing materials, you can see why there are a lot of flat roof garages around.
Does this also mean that a flat roof is the best roof you can choose? Certainly not always. Decades ago, a flat roof really was virtually flat. These roofs did have a draining system, but there weren’t any hard and fast rules as to how much of an angle you have to build into the roof. So if you have a roof which is flat and around 20 to 30 years old, you might find that water tends to gather on the middle of the roof during the wet seasons. If water remain standing on the roof during late autumn and into winter, you could suddenly have a very large mass of solid ice up there. When water freezes, it expands, which means powerful forces are now pushing and pulling in the roof cladding, possibly causing leaks in the process. Later, roofers acknowledged the fact that totally flat roofs are deeply flawed, and nowadays there are much more strict rules about how flat exactly a roof can be.
The bottom line is, flat roof can still work, but you have to make sure that water can be drained from the roof surface and won’t remain standing there. No matter how waterproof you think a construction is, if you let water remain on your roof for an extended period of time, it will find its way through the membrane. Remember that, when you design your next flat roof.
