HomeFlat Roofing
TPO and EPDM membrane for flat and low-slope roofs.
Shingles are built to shed water off a slope. A membrane is built to stop water that has nowhere to go but sit. We install single-ply TPO and EPDM on additions, porch roofs, garages and commercial buildings across Boone County, sealed at the seams and flashed at every penetration.
Why a shingle roof and a flat roof solve different problems
A pitched roof works by shedding water. Gravity pulls rain down the slope, off the eave, and into the gutter before it has time to find a way in. Shingles are designed around that assumption; every lap, every course, every nail placement counts on the water moving downhill fast.
Below roughly a 2:12 pitch, water stops moving fast enough for shingles to do their job. It sits, it wicks sideways under the laps, and it finds every fastener hole a shingle roof was never meant to be watertight against. That is the line where a roof stops being a shedding system and needs to become a fully sealed, waterproof membrane instead: additions, porch roofs, garage tie-ins, bay window tops, and most commercial buildings all fall on the low-slope side of that line.
We see the mismatch most often on additions built onto an older house, where a contractor shingled a roof section under a 2:12 pitch because it matched the main roof visually. It looks right for a few years and then leaks at every valley and penetration, because shingles were never the right material for that slope in the first place. If that describes what is happening at your house, the fix is not a better shingle, it is switching the whole section to membrane.
TPO or EPDM: what actually separates them
Both are single-ply membranes, both come in wide rolls, and both are a completely different install method than shingles. Past that, they diverge in ways that matter for which one belongs on your roof.
How the seams get sealed
TPO is a thermoplastic, which means the seams are heat-welded: a hot-air welder melts the top and bottom sheets together into a single continuous membrane at the lap. Done correctly, a heat-welded seam is often stronger than the membrane around it. EPDM is a thermoset rubber, so it cannot be heat-welded. Its seams are joined with seam tape or a liquid adhesive instead, which works well when installed correctly but is the part of an EPDM roof most likely to need attention over the years, since adhesive bonds age differently than the rubber sheet itself.
Color and heat
TPO is manufactured white (other colors exist but white dominates the market), which reflects sunlight and keeps the roof deck and the building below noticeably cooler in summer. EPDM is naturally black and absorbs heat. On a shaded low-slope section where reflectivity does not matter much, that is a non-issue. On a sun-exposed commercial roof, the color difference shows up directly in cooling costs.
Flexibility and aging
EPDM stays flexible in cold weather better than most thermoplastics, which is one reason it has stayed popular in northern climates for decades. It is also generally forgiving of minor foot traffic and small punctures, since the rubber sheet resists tearing rather than cracking. TPO's weak point historically was UV embrittlement in older formulations; current TPO membranes have largely resolved that with improved polymer blends, but it is still the reason we buy membrane from manufacturers with a long track record rather than the cheapest roll on the shelf.
Membrane options for flat and low-slope roofs
| System | Thickness | Seaming | Best fit |
|---|---|---|---|
| TPO | 45, 60 or 80 mil | Heat-welded | Sun-exposed roofs where reflectivity cuts summer heat load, and any job where seam strength matters most. |
| EPDM | 45 to 90 mil | Taped or glued | Shaded low-slope sections, colder applications, roofs with irregular penetrations where the rubber's flexibility helps at flashing details. |
| Modified bitumen (what many older flat roofs already have) | Varies by ply | Torch-applied or self-adhered | Common on roofs built before single-ply became standard. We tear it off rather than overlay it in most cases, since trapped moisture under an old built-up roof rarely shows itself until the membrane is open. |
Neither TPO nor EPDM belongs under a shingle pitch, and shingles do not belong under a low-slope pitch. If your roof has both a steep main section and a low-slope addition, the two materials meeting at the tie-in is the single most common leak point we get called out for, and it is usually the first thing we check on a standard roof replacement quote when a house has an addition.
How a flat roof job runs
- Roof evaluation. We check the existing membrane, the slope toward drains or scuppers, ponding areas, and probe the insulation for trapped moisture.
- Tear-off or overlay decision. Membrane can sometimes go over a sound, dry single-ply roof. It never goes over ponding water, wet insulation, or a torn membrane, because trapped moisture under a new roof rots the deck faster than an open roof would.
- Deck and insulation prep. We install or replace cover board and, where ponding is a recurring problem, tapered insulation to correct the slope toward the drains.
- Membrane install. Fully adhered or mechanically fastened depending on the deck, with seams heat-welded on TPO or taped on EPDM.
- Flashing at every penetration. Pipe boots, wall terminations, drains and scuppers are where flat roofs actually fail. This step gets more attention than the field membrane itself.
- Walk-through and cleanup. We check the seams, confirm drainage, and walk the roof with you before we call it finished.
Warranty
Every roof we install, including TPO and EPDM membrane systems, carries our 5-year workmanship warranty.
Recent flat roofs
What homeowners and building owners ask us about membrane roofs.
Anything under about a 2:12 pitch, roughly a rise of two inches over twelve inches of run, needs a sealed membrane rather than shingles. If you are unsure what your slope is, we measure it for free during the inspection and tell you honestly which category your roof falls into.
Almost never the field of the membrane itself. It is nearly always a flashing detail: a pipe boot that dried out, a wall termination that pulled loose, a drain that clogged and let water sit higher than the flashing was designed for. That is why we spend more labor on penetrations and edges than on the flat field.
Brief ponding after a heavy rain that drains within a day or two is normal on most low-slope roofs. Water that sits for 48 hours or longer usually means the slope toward the drains is wrong, and that gets corrected with tapered insulation rather than just a thicker membrane.
Sun-exposed roofs benefit from TPO's reflectivity and heat-welded seams. Shaded sections, colder applications, or roofs with a lot of odd-shaped penetrations often do better with EPDM's flexibility. We walk both options with you before you decide.
Only if the existing membrane is dry, sound, and free of ponding. Older built-up or modified bitumen roofs often hide trapped moisture in the insulation below, so in most cases we tear off rather than risk sealing wet insulation under a new membrane.
Both. Residential additions and porch roofs are common, and we also install and repair TPO and EPDM on commercial buildings across Boone County. If your building also needs new gutter installation at the roof edge, we can scope both at once.
Within 24 business hours, and usually sooner. Calling gets you a person fastest during office hours, Monday to Friday, 9:00am to 5:00pm.
Yes to both. Projects start with 50% down, which reserves your spot on the schedule and orders material, and the balance is due once the work is finished and you have walked it with us. Financing is available on larger projects, so ask us about options when we come out.
Where to next?
We will check the slope, the seams and the flashing, and tell you what it needs.
No charge, no obligation. If the roof only needs a repair at the flashing, that is what we will quote.
(765) 335-6475Monday to Friday, 9:00am–5:00pm · or text us
Book online in about a minute.
Pick a day and time that works for you and it goes straight onto our schedule. No waiting on a callback.
Get a Free Estimate- Free on-site look, no charge either way
- You keep every photo we take
- We answer every call and text within 24 business hours