Not every roofing system in Seattle, WA should receive the same waterproofing specification. As a top level Master Contractor we like to think of ourselves as “Roof Doctors.” Instead of just prescribing the same medicine to everyone its important to diagnose every patient and to get them the specific treatment that will cure their ailment. In the same manner every roof structure should be approached with the mentality of needing to diagnose the need based on a few factors including:
Roof Pitch
Existing Insulation
Wind Conditions
Existing Layers On Roof
Is There Rot In The Structure
In cases where the roof has less than 3 inches of rise in 1 foot asphalt shingles are not the correct waterproofing application. With low slope or low pitch roofs there are a few viable options including torchdown roofing systems. Here is a description of torchdown from Polyglass, one of the best torchdown membranes on the market:
“Polyglass’ APP (Atactic Polypropylene) modified asphalt roofing membranes are reinforced with polyester and/or fiberglass mat offering excellent tensile strength and dimensional stability. Polyglass APP membranes can be heat-welded or cold-applied and are meant to be applied directly over an acceptable substrate or as part of a multi-ply system.”