Metal Roofs – Part III of What is the pitch of my roof and why do I care?
Typically a roof pitch of 3:12 or better is required to be able to use shingles or metal roofing; anything less than that should be using a flat or low sloped product. When choosing roofing products the slope and location of the roof should be the determining factor. I have many people tell me they want metal roofing because it has no maintenance, however if you live in an area like ours with great temperature fluctuations you have to be careful what types of metal you use. Metal moves at a different rate than your wooden roof deck, so the differing movement will work to loosen the fasteners. Also if you live in a hail prone area you need to be aware that hail may dimple your roof and cause cosmetic damage that the insurance won’t cover because it doesn’t damage the integrity of the roof itself. So you will be stuck with a roof that looks dented and may not be able to replace it.
Another reason people give me for wanting metal roofs is so that snow will not stay on the roof. Unless you are in a region that gets a ton of snow the weight of snow on a properly designed roof should not be an issue. What is an issue is when that snow comes off the roof and tears off gutters, deck railings, and buries your vehicle. You will then be looking for ways to keep the snow on your roof, this is done by installing snow guards, which can be expensive, there are numerous types from small plastic shoes that attach to the roof to a series of one or more rods attached at the eave to keep the snow from avalanching off the roof.
There are some great options for metal roofs, Stone coated metals that look like shingles, shakes or tile are smaller panels and so are not subject to the same expansion and contraction problems and the stone coating helps hide dents caused from hail. Standing seam metal is another product that uses clips to attach the roofing to the roof deck so as the metal moves it slides under the clip and doesn’t loosen the fasteners. Please ask a lot of questions and talk to several contractors before choosing a metal roof for your home. Many contractors will tell you what you want to hear and unless you ask questions won’t give you the information you need to make an informed decision. Metal roofing may be a great choice for you, but it may not be.