Short answer
For a small low slope roof, buy one EPDM sheet big enough to cover the whole roof plus enough to turn down over the edges, so you have no seams to make. Common thicknesses are 45 and 60 mil; thicker resists punctures better. You also need the maker’s bonding adhesive, plus seam tape and primer if you have any seams, and edge trim or drip edge. Kits bundle these.
Why EPDM on a flat roof
Asphalt roll roofing relies on water running off over its laps, which is why it needs slope. A single EPDM sheet has no laps in the field at all, so it tolerates the low slopes of garage and extension roofs much better. The weak points move to the edges, seams and anything that pokes through the roof. Hunker puts EPDM life at more than 20 years and gives a cost of $5 to $9 per square foot installed (Hunker).
What to buy
-
01Easiest start
EPDM roofing kit
Best for: garages, sheds and extensions under about one sheet in size
- Includes
- sheet + adhesive (check)
- Thickness
- often 45 mil
- Seams
- none if one sheet fits
- Check exactly what the kit includes: membrane, adhesive, seam tape, primer, trims.
- Measure the roof plus overhang and upturns before choosing a size.
-
02Tougher
60 mil EPDM sheet
Best for: roofs with foot traffic, trees overhead or hail
- Thickness
- 60 mil
- Sold
- by size or by the foot
- Elevate lists RubberGard EPDM in 45, 60 and 90 mil (Elevate).
- Heavier and stiffer to handle; get help on a windy day.
-
03Required
EPDM bonding adhesive, primer and seam tape
Best for: gluing the field and making any seam
- Adhesive
- membrane maker’s
- Seams
- primer + tape
- Only EPDM rated products bond reliably to the rubber.
- Follow the open time on the can: too soon or too late and it will not grip.
Before you start
- Check the drainage. Water should run off within a day or so of rain. Fix ponding first.
- Check the deck. Soft or rotten boards must be replaced; the sheet follows every bump.
- Plan edges and walls. Where the roof meets a wall, the sheet turns up and gets flashed. At open edges it turns over drip edge or trim.
- Pick a dry, calm, mild day. Adhesive needs the temperatures on its label, and a big sheet catches wind.
Comparing options? See TPO roofing, peel-and-stick roll roofing and roll roofing for flat roofs.
Questions people ask
Is 45 mil or 60 mil EPDM better?
Sixty mil is thicker, so it handles foot traffic, hail and branches better and costs more. Forty-five mil is common on small DIY roofs. Elevate (formerly Firestone) makes RubberGard EPDM in 45, 60 and 90 mil. Pick by how much abuse the roof will take and what the warranty requires.
What size do EPDM rolls come in?
Retail sheets range from small patches to wide sheets sold by the foot. Hunker notes 10 by 25 foot rolls are commonly sold. Measure the roof, add enough for the edges and any upturns at walls, and buy one piece if you can.
Can EPDM go on a sloped roof?
It is made for flat and low slope roofs that still drain. On steeper roofs, shingles or roll roofing are usually simpler. Check the maker’s limits.
How long does EPDM last?
Hunker estimates EPDM can last more than 20 years. Life depends on thickness, sun, detailing at edges and penetrations, and how well seams were made.
Can I use any glue or caulk on EPDM?
No. Use the adhesives, primers, tapes and sealants made for EPDM, ideally from the membrane maker. Many general purpose products do not bond to rubber or can damage it.
See EPDM rubber roofing rolls on Amazon
Sources
Last reviewed October 12, 2026. Products and listings change; check the data sheet and wrapper before you buy, follow the maker’s instructions, and check your local building code.