Carlisle Sure-Seal EPDM 90-mil: Heavy-Duty Spec for Equipment Pads & High-Traffic Roofs
Published: 2026-06-11
Carlisle Sure-Seal 90-mil EPDM is the heavy-duty option in the EPDM lineup. It's not about waterproofing performance — a properly installed 60-mil EPDM roof won't leak for 25+ years. The 90-mil thickness exists for one reason: mechanical robustness. When you're placing a 5,000 lb HVAC unit on a roof, running refrigerant lines across it, and sending techs up there quarterly for maintenance, the membrane under and around that equipment takes abuse that a standard roof section never sees.
Spec 90-mil EPDM under any rooftop equipment exceeding 5 tons, within 10 feet of equipment access paths, and under any area where tools or equipment are regularly placed. The cost premium is approximately $1-1.50/sf over 60-mil — about $1,000-1,500 per 1,000 sq ft. This is less than the cost of one puncture repair during the roof's lifetime.
🛡️ Insurance & Compliance Advisory90-mil EPDM is the spec for roofs with heavy mechanical equipment (HVAC units over 5 tons, cooling towers, generator pads). The extra thickness is not for waterproofing — 60-mil handles that — it's for puncture resistance from service traffic and dropped tools during maintenance. Adjusters: if a 60-mil roof had equipment installed post-construction and is now leaking, check whether 90-mil should have been spec'd under the equipment per manufacturer requirements. Incorrect membrane thickness under equipment can void the warranty.
Equivalent Products & Cross-References
| Equivalent / Alternate Product | Action |
|---|---|
| Firestone RubberGard EPDM 90-mil | |
| JM EPDM 90-mil |
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Frequently Asked Questions
Can I use 90-mil EPDM for the entire roof instead of just under equipment?
Yes, but it's rarely cost-effective. The waterproofing performance is identical — 60-mil EPDM doesn't leak because it's 60-mil; it leaks because of installation errors or mechanical damage. Use 90-mil selectively under equipment pads, access paths, and roof areas with high service traffic. For the field of the roof, 60-mil is sufficient for all FM Global wind uplift classes up to 1-120.
Related Roofing Materials
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References & Industry Standards
- ASTM International. Standard Specifications for Single-Ply Roofing Membranes. astm.org
- FM Approvals. Factory Mutual Roofing Assembly Standards. fmapprovals.com
- UL LLC. Fire Classification of Roofing Materials. ul.com
- NRCA. The NRCA Roofing Manual. nrca.net