Tool
Which low-slope system suits the building
The membrane is chosen for the building, the equipment on it and how it drains. Get those three right and the brand argument mostly disappears.
This works out an answer as you change the controls, which needs JavaScript. Without it, the reference section below covers the same ground, and we are happy to talk it through.
The five systems, plainly
| System | Where it belongs | What to know |
|---|---|---|
| TPO | Large simple planes, warehouse and retail | Heat-welded seams, reflective surface. The volume choice, and a good one when the building suits it. |
| PVC | Restaurants, labs, anywhere with grease or chemical exhaust | Chemically resistant and heat-welded. The right answer where TPO and EPDM would be degraded. |
| EPDM | Simple rectangles with few penetrations | Mature, economical, easy to repair. Attention goes to seams and terminations. |
| Modified bitumen | Roofs with heavy foot traffic and lots of detail | Takes traffic well and patches easily in place, which matters on an occupied building. |
| Standing seam metal | Visible rooflines, long horizons, few penetrations | Outlives membranes by a wide margin on the right building; wrong on a roof crowded with equipment. |
Four of the five join their sheets differently, and the drawing below cuts through each lap so the distinction the ranking turns on is visible.
Ponding is a drainage defect, not a membrane choice. If water stands on the roof, the membrane over it has to tolerate that, but the thing to fix is the drainage.
Specification starts with somebody on the roof, not with a form.
Talk to us about the buildingAll work is performed by licensed and insured local roofing professionals.