Flat roofing in Oregon and Washington requires a number of technical considerations. First, we have one of the wettest, most tree debris-laden environments in North America. Secondly, we have substantial periods of high humidity and cold weather that can create condensation under the roof surface. We have unique building shapes and designs with a variety of exterior sidings and claddings. Therefore, we must be very careful when designing and applying flat roofs in the Northwest.
Regional and national industry experts have determined that in Oregon and Washington require an interior moisture proofing element as well as exterior waterproofing. If you are considering a flat roofing project, it is critical to be educated on both the interior and exterior aspects of this roofing. In some cases, insulation is added above the wood substrate of the roof. This creates a condensation barrier and increases energy efficiency. Often, we also add slope to a roof that might be holding water. Homeowners need to be aware of any issues that might occur as a result of this added slope.
The most common roofing materials used in the northwest are asphalt shingles, fiberglass shingles, wood shakes, and standing seam metal roofs. These four categories are further broken down into two subcategories: flat roofing and metal roofing.