With memberships in several business associations, Dr. Roof General Contractors has long been caring for houses since 1998. Portland homeowners can depend on them for total roof substitution working with a range of products. Composition Roofing TPO Roofing For small slope and flat roofs, we endorse TPO, or thermoplastic olefin, https://us.enrollbusiness.com/BusinessProfile/7564164/Premium%20Roofing%20Systems