Pitched roofs are those that are visible as you approach a building. This type of roofing system will likely be best for snow and rain. Melting snow and summer rain will be able to make its way off the roof leaving less risk of water damage.
There are many material options for pitched roofs, including shingles, wood shake, tile, metal or slate. For areas with heavy snow accumulation, metal might be preferable because other materials may lead to costly ice damage issues. Depending on the specific factors affecting your facility or building, metal options range from cold-rolled steel or zincalume to painted steel, painted aluminum, or even copper or zinc.
One of the most important decisions you can make for a pitched roof is the underlayment because it will impact its durability. For example, a #30 felt is the typical underlayment for tile and metal; however, synthetic or modified underlayments tend to have a longer service life.
Heavy Rain / Strong wind
Either a pitched roofing system or a flat roof would be ideal for heavy rain and strong winds with each having its pros and cons. The advantage of a pitched roof is water drains rapidly. The downside is that depending on how strong the wind is roof material can be stripped away, or in a worst-case scenario, the roof can uplift and detach from the walls.
If properly installed, flat roof systems will hold up to strong winds, but are more susceptible to water leakage after heavy rain. With proper maintenance and annual inspections, this roofing system is also a great fit for many building facing heavy rain and strong winds, but just be sure to use a material that is continuous with no open seams.
Materials make all the difference. For a pitched roof, shingles are the most popular because of their water resistant properties. However, they are not waterproof and rely heavily on the roof’s slope to drive water off the roof. Again, metal could also be a good choice for these types of weather conditions. Materials for a flat roof include TPO, PVC, built-up systems and spray polyurethane foam, — to name a few — and each has its benefits. For example, spray polyurethane foam is fairly simple to maintain and provides insulation and soundproofing.
Dry Heat / Summer Storms
In dry desert climates like Arizona, Utah and Nevada, a pitched or flat roofing system will work. However, with both roofing systems, you need to consider that thermal shock is a possibility. Thermal shock occurs when a roof that has been baking in the sun is rained on. The rain rapidly draws heat out of the roofing material, causing it to shrink as it cools. This rapid cooling can cause the roofing material to crack because it is shrinking on the surface faster than the bottom can accommodate. With rain, the roof temperature may drop as much as 100 degrees F. within a matter of minutes, which places a severe strain on the roof system.
As for materials, the flat roof materials (mentioned above) are standard. However, it is key to note that the heat and sun damages organic roofing materials faster than elsewhere and regular maintenance is encouraged. For a pitched roof, you can get creative and have anything from metal to shingle, to tile. If you choose to go with tile, they are available in a selection of profiles and colors ranging from hand-made sun-dried “sandcast” tile to clay and concrete.