I recently purchased a home where part of the roof is not sloped enough for shingles. My home inspector said that portion was roll on roofing and was in good shape. However, he advised me, that the roll on portion would only have a life of 5-7 years and would need redone. When it’s time to redo, are there other roofing materials to consider that would have more longevity?
Your inspector is correct. While many factors can impact the life of a roof, having a low slope is definitely one of them. This type of roofing materials will not have the longevity of the more common asphalt shingle roofs, which require at least a 3:12 pitch (roof slopes downward 3″ over 12″).
One option that would provide additional longevity is EPDM (Ethylene Propylene Diene Terpolymer), which is commonly referred to as “Rubber Roofing”. EPDM is flexible and handles both hot and cold weather cycles, often lasting for decades. Just remember that details count when installing any roof, and are especially important with low-slope roofing. The flashing between EPDM and any intersecting walls or protrusions like plumbing vents or chimneys must be well done to avoid any leaks.
The other low-slope option to consider is modified bitumen. This asphalt based roofing is less expensive than EPDM and provides an effective seal, but will not last nearly as long. One version requires a torch to apply which can be dangerous in the hands of anyone who doesnt use it regularly so this roof is best applied by a professional. Modified Bitumen is also available in a peel-n-stick version as well, which may be better suited for DIY’rs.