Where we live matters when we design our buildings. The local weather conditions can make a big difference on the durability of a building – and a garage is no exception. Roofing a garage often starts with the choice between flat roof and pitched roof, and what choice you make makes a difference – depending on where you live. Let us look at a couple of examples.
A flat roof garage and snow
If you live in an area with a lot of snowfall in the winter, you may be wondering whether having a flat roof garage is a good idea. Normally, a roof is designed to take a certain load – both downward pressure, but also lateral pressure from strong winds. A snow-covered roof will experience an extra down load, which is typically described in engineering handbooks as a multiplying factor. I will not get into the math of calculating loads on a roof construction, since this is something best left to engineers, but this factor will vary between locations, depending on the average snowfall in a given area. Therefore, if you live in such an area – or you suspect that you do – do yourself the favor of consulting a local engineer, or checking with the local building codes. Simply relying on your own gut feeling or what a contractor tells you may not be enough. A pitched roof will have slightly better characteristics when it comes to snowfall, but since heavy snowfall usually means that the snow will be packed on the roof, you could end up having almost the same amount of snow on a pitched roof, as you would a flat one.
The effects of heavy rainfall
Rain is of course different from snow, in that it will always drain off completely, given a normal functional roof. Especially with a flat roof, you must pay great attention to the roof in both the construction phase and when the roof is in use. It does not take much of a hollow for water to gather for a longer duration, potentially penetrating the roof surface somehow, somewhere. Keeping the guttering and downspouts absolutely clear of debris also becomes essential – especially when the roof has a parapet around its perimeter. If not, then the only escape for the water is blocked, and you will have a miniature lake on top of your roof in no time. Disaster will be imminent in this case. Whether you go with a pitched or flat roof, you will want to make sure that your guttering is fully functional and adequate in terms of how much water it can transport.
Follow these simple pieces of advice, and you will have done much to make your garage roof compatible with your local climate.