Why low-slope sections need their own playbook
Plenty of houses on the South Hill near Manito Park carry a flat or near-flat section somewhere - a porch roof, a dormer connector, a rear addition, or a full mid-century flat deck. Water does not run off these the way it sheets down a pitched roof. It pools, it lingers, and it works its way under any seam that has loosened. That is why a low-slope roof has to be treated as a continuous membrane rather than a field of overlapping shingles.
On the older, established homes in Comstock we often find a patchwork of past repairs: layered roll roofing, tar that has gone brittle, and flashing that was never tied into the membrane correctly. Each of those transitions is a place standing water can find its way in.
What TPO brings to a Comstock roof
TPO (thermoplastic polyolefin) is a single-ply membrane that is heat-welded at every seam. Instead of relying on adhesive or sealant that ages out, the seams become one fused sheet of material - which is exactly what you want on a surface that holds water and snowmelt through a long Inland Northwest winter.
- Hot-air welded seams that resist the wind-driven moisture common up on the hill
- A reflective white surface that eases summer heat load on flat decks
- Flexibility through freeze-thaw, so the membrane moves with the deck instead of cracking
- Clean detailing around drains, scuppers, vents, and parapet walls
For full and partial flat roofs alike, TPO gives you a predictable, serviceable surface that an installer can inspect and maintain for decades.
Snow, ice dams, and the freeze-thaw cycle
The mature tree-lined streets of Comstock are beautiful, but they also mean shade that holds snow on a flat deck long after the sun has cleared open roofs. Snow that sits, then partially melts, then refreezes overnight is the engine behind ice dams and standing water. On a low-slope roof there is no pitch to bail you out - the membrane and the drainage detailing are doing all the work.
We design the drainage path first: where does the water go, and does it actually get there before it freezes? Proper tapered insulation, correctly placed drains or scuppers, and welded flashing at every wall transition keep meltwater moving instead of ponding and pushing back under the system.
Tie-ins where flat meets steep
Many Comstock homes are not fully flat - they pair a steep main roof with a low-slope addition or porch. The junction between the two is one of the hardest details to get right, and it is where a lot of failures hide. The TPO membrane has to be carried up the wall, flashed, and integrated cleanly with the shingle field above it so that water sheeting off the steep roof never gets a chance to drive under the flat section.
If your home mixes roof types, you may also want to look at how we handle pitched surfaces. You can read more on our roof replacement page, since a sound transition depends on both systems being installed to work together.
Working with DG Contracting
DG Contracting has served Spokane-area homeowners since 2013, and we are a GAF Master Elite contractor - a credential held by only the top 2 to 3 percent of roofers nationwide. We are licensed and insured in both Washington and Idaho.
- 15-25 year workmanship warranty backing the installation itself
- GAF Golden Pledge coverage with 25 and 50-year options on qualifying systems
- a 15-25 year workmanship warranty with a roof replacement
- Flexible financing and free, no-pressure estimates
Every estimate starts with a real look at how water moves across your specific roof, not a guess from the driveway. Call (509) 209-1894 to set up a visit.
