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Flat and low-slope roofing
TPO and modified bitumen for additions, dormers, and porches, installed with real slope so water drains instead of sitting.
Get a free estimateThe parts of the roof a shingle cannot cover
Plenty of valley homes have a low-slope section: a converted porch, a mid-century wing, a dormer, a garage addition. Shingles need pitch to shed water and will leak on anything close to flat. Those areas need a membrane system.
What we install
- TPO single-ply membrane, heat-welded seams
- Modified bitumen (torch or self-adhered) for smaller sections
- Tapered insulation to build slope toward drains
- New edge metal, drains, and scuppers
Not sure yet? We will look at it, tell you what we find, and put a written number on repair and on replacement so you can choose.
Built for this climate
What matters here in Oregon
On a low-slope roof in Oregon the enemy is ponding: water that sits in a low spot for days after the rain stops. It finds every seam and accelerates aging. The fix is slope, built in with tapered insulation, plus drains and scuppers that are actually at the low point.
Older valley flat roofs are often built-up tar and gravel near the end of their life, or a failed rolled roof with lap seams lifting. A modern welded TPO membrane is a large step up in reliability.
We flash the transition where the low-slope meets the main pitched roof carefully, because that intersection is where most of these systems leak.
How it goes
The process, start to finish
- Inspect. We check the current slope, the drains, and where water is sitting or getting in.
- Design the slope. We lay out tapered insulation so water runs to the drains, and quote it in writing.
- Tear-off. The failed membrane or built-up roof comes off down to solid deck.
- Membrane. Insulation, membrane, and heat-welded seams go down, with new edge metal and drains.
- Detail and check. Transitions and penetrations flashed, water-tested, cleaned up, warrantied.
Common questions
Good to know
Which membrane is best for my flat roof?
TPO is the common choice for most residential low-slope areas: durable, reflective, welded seams. Modified bitumen suits smaller or heavily trafficked sections. We match the system to the area.
Why does my flat roof pond water?
Usually because it was built dead flat or has settled, and the drains are not at the low point. Tapered insulation rebuilds the slope so it drains.
How long does a TPO roof last?
A properly installed and drained TPO roof gets 20 to 25 years. Ponding water is the main thing that shortens it.
Can you just recover it instead of tearing off?
Sometimes, if the existing roof is dry and sound. If there is trapped moisture or multiple old layers, a tear-off is the only real fix.
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“Your satisfaction is our priority”
Tell us what is going on with your roof. We come look, put a real number on it, and give you the honest option.