Roofing systems
EPDM roofing.
Synthetic rubber sheet with a long track record. Easy to repair, and still named in many specs for low-slope commercial roofs.
What it is
A rubber membrane with taped seams.
EPDM (ethylene propylene diene monomer) is a synthetic rubber sheet, usually black, sometimes white. Unlike TPO and PVC it is not welded. Seams are joined with seam tape and primer, and the flashing details use the same family of tapes and cured or uncured flashing.
Sheets come in large widths, so a roof has fewer seams. The membrane stays flexible in heat and cold and is simple to patch years later.
The assembly
What goes on the deck.
At a glance
EPDM in numbers.
- Product standard
- ASTM D4637
- Common thickness
- 45, 60 or 90 mil
- Seams
- Seam tape and primer
- Attachment
- Fully adhered, mechanically fastened or ballasted
- Color
- Black, or white on request
- Typical buildings
- Office, institutional, older commercial roofs
Where it fits
Where specs call for EPDM.
- Roofs where the owner wants a membrane with decades of field history
- Replacements where the spec already names EPDM
- Roofs with structure that can carry ballast, where the spec calls for it
Black EPDM absorbs heat. On a building where the cooling load matters, the spec may call for white EPDM or a reflective single-ply instead. Seams and flashings need careful work, so we photograph each detail before the next layer covers it.
How we price it
Quantities first, then the details.
Field area, perimeter, curbs, drains and penetrations come off the roof plan and details. Seam tape, primer, flashing and termination bar are priced per linear foot or per item, with waste. The insulation and cover board are their own lines, so an alternate is easy to compare.
In the field
Where EPDM roofs need care
Older downtown roofs 
Drains and scuppers 
Curbs and penetrations
FAQ
Questions GCs and owners ask.
Is EPDM still a good choice in Texas?
Yes, for the right building. It handles heat and cold, and repairs are simple. Black sheet runs hot in summer, so reflectivity is the main question in North Texas.
How are EPDM seams made?
With seam tape over primed laps, rolled in place. Seam quality is about clean, dry surfaces and full contact. We check them before the roof is closed out.
Can EPDM be repaired after hail?
Usually. Punctures and cuts take a patch of EPDM with seam tape. Widespread damage or wet insulation below is a different conversation. See roof repair.
Related
Compare systems, or plan a replacement.
Have an EPDM roof out for bid?
Send the invitation. Link the drawings and spec, give the bid date, and we'll confirm we have them and whether we're bidding.