Low-Slope and Flat Roofing
"Flat" roofs are not flat — they are pitched just enough to drain, typically a quarter-inch per foot. Below roughly 3:12, shingles stop working because they rely on gravity to shed water faster than it can work sideways under the laps.
The three systems we install
- TPO — a single-ply thermoplastic membrane with heat-welded seams. White and reflective, which cuts summer heat gain. The most common choice for residential low-slope sections and small commercial.
- EPDM — synthetic rubber, typically black, seams bonded with adhesive or tape. Very durable, handles temperature swings well, easy to repair.
- Modified bitumen — asphalt-based sheet, torch- or self-adhered. Multi-layer redundancy and good for foot traffic areas like a deck-over.
On a home with a low-slope addition, porch, or dormer roof, the transition detail where the low-slope section meets the pitched shingle roof is the most common failure point. It has to be done as a proper transition, not just lapped.
Low-Slope Roofing Costs
| System | Installed per square | Life |
|---|---|---|
| TPO membrane | $700 – $1,100 | 20 – 30 yrs |
| EPDM rubber | $750 – $1,200 | 20 – 30 yrs |
| Modified bitumen | $800 – $1,300 | 15 – 25 yrs |
| Silicone or acrylic restoration coating | $300 – $650 | 10 – 15 yrs, renewable |
| Localized membrane repair | $400 – $1,600 (flat fee) | — |
Where Roof Leaks Actually Come From
In our experience across the Salt Lake Valley, the overwhelming majority of leaks trace to one of these — and only a small minority are a failure of the shingle field itself.
| Source | How it shows up | Typical fix |
|---|---|---|
| Pipe boot / vent collar | Stain in a hallway or bathroom ceiling, often a few feet off the plumbing stack | $275 – $650 |
| Chimney or wall flashing | Stain along an interior wall line, worse in wind-driven rain | $500 – $1,600 |
| Valley | Stain appears mid-ceiling during heavy or sustained rain | $700 – $2,200 |
| Ice dam at the eave | Wet spot near an exterior wall, only in winter | $1,200 – $4,500 |
| Skylight | Drip directly at the skylight curb | $550 – $1,800 |
| Nail pops / lifted shingles | Intermittent, hard to reproduce, often wind-dependent | $350 – $900 |
| Gutter overflow behind fascia | Water inside the wall near the eave, not the ceiling | $300 – $1,200 |
| Low-slope section with shingles | Recurring, worsens every year, never fully fixed | Membrane replacement |
Flat & Low-Slope Roof Repair FAQs — the Salt Lake Valley
TPO or EPDM?
TPO is white and reflective, which helps with summer heat gain, and its seams are heat welded. EPDM is black rubber, extremely durable, and easy to repair. Both are good; TPO is what we install most often on residential low-slope sections here.
Can a flat roof be coated instead of replaced?
Yes, if the membrane and insulation underneath are dry and sound. A silicone coating system costs roughly a third to a half of a replacement, adds ten to fifteen years, and is renewable. If the insulation is wet, coating over it just seals the moisture in.
How much does a roof repair cost?
Most repairs land between $275 and $2,200. A cracked pipe boot is at the low end; a valley re-line with wet decking underneath is at the high end. Repairs above roughly $2,500 are worth comparing directly against a replacement quote.
Should I repair or replace?
If the roof is under about 15 years old, the damage is localized, and the decking is dry, repair. If shingles are curling or losing granules across whole slopes, the mat is showing, or you have had repeat leaks in different spots, replacement is the better spend. We will tell you which one you actually have.
Can you repair just one section?
Yes, and we do it often. The honest caveat is shingle matching — on a roof more than about eight years old, a new patch will not weather-match the surrounding field. On a back slope that is usually fine. On a front elevation it may bother you.
Do you warranty repairs?
Yes. Repairs carry a workmanship warranty on the specific work performed. It does not extend to the rest of an aging roof, and we will tell you plainly at the time if the rest of the roof is likely to need attention soon.
Free flat roof inspection in the Salt Lake Valley
Photo documented, written, and yours to keep. If your roof does not need work, we will tell you that — and we will put the remaining life in writing.
More Roofing Guides for the Salt Lake Valley
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- Affordable Roofing in the Salt Lake Valley
- Roof Repair Cost in the Salt Lake Valley
- Roof Leak Repair Cost in the Salt Lake Valley
- Roof Installation Cost in the Salt Lake Valley
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- Roof Inspection Cost in the Salt Lake Valley
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