Skip to content
Johns Manville ENRGY 3 4.3 in. x 4 ft x 8 ft Polyiso Roof Insulation Board, Grade II (20 psi)
Regular price $75.76Orders start at $399 — combine any items to reach the minimum. Learn more
Johns Manville ENRGY 3 4.3 in. x 4 ft x 8 ft Polyiso Roof Insulation Board, Grade II (20 psi)
This Johns Manville ENRGY 3 board is a 4.3 in. thick, 4 ft x 8 ft Grade-II flat polyiso roof insulation with a closed-cell foam core and glass-reinforced facers. One board is one sell unit covering 32 sq ft. It installs mechanically fastened, with urethane adhesive or hot asphalt beneath JM single-ply and multi-ply systems.
Key Features:
- High R-Value Core: The closed-cell polyisocyanurate foam core provides high R-value per inch.
- Durable Facers: Glass-reinforced facers give rigidity and resistance to indentation and crushing.
- Steel Deck Rated: Approved for direct application to steel decks.
- 20 psi Grade II: Meets ASTM C1289, Type II, Class 1, Grade 2 (20 psi compressive resistance).
- System Compatible: Compatible with BUR, modified bitumen and single-ply (TPO, PVC, EPDM) systems.
- Code Approvals: UL Classified, FM approved, Miami-Dade County and Florida Building Code approved, PIMA QualityMark certified.
- LTTR 25.5: The 4.3 in. thickness carries an LTTR value of 25.5 (hr-ft2-F)/BTU per the JM data sheet.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Johns Manville |
| Manufacturer model | 90016271 |
| Sell unit | 1 board, 4 ft x 8 ft x 4.3 in. |
| Product line | ENRGY 3 |
| Material | Closed-cell polyisocyanurate foam core with glass-reinforced facers |
| Color | Tan |
| Dimensions | 4 ft x 8 ft, 4.3 in. thick |
| Thickness | 4.3 in. |
| Compressive strength | Grade 2 (20 psi minimum) |
| Coverage per unit | 32 sq ft per board |
| Standards | ASTM C1289 Type II Class 1 Grade 2; CAN/ULC S704 Type 2 & 3, Class 3; UL 790, 263, 1256; FM 4450/4470 |
| Certifications | PIMA QualityMark certified, UL Classified, FM Approved, Miami-Dade County approved, Florida Building Code approved, Title 24 compliant, LEED |
| Weight | 23.942 lb per board |
Coverage & How Much You Need:
Each 4 ft x 8 ft board covers 32 square feet of roof deck; divide total roof area by 32 to size board quantities.
Fit and Compatibility:
Eligible for approved JM Peak Advantage roofing guarantees and compatible with JM TPO, PVC and EPDM single-ply systems as well as BUR, APP and SBS multi-ply systems, installed mechanically fastened, adhered or with hot asphalt. Fasteners, plates, adhesives and membranes are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included in one order?
A: One 4.3 in. thick, 4 ft x 8 ft ENRGY 3 Grade-II polyiso roof insulation board.
Q: How many boards do I need for my roof?
A: Each 4 ft x 8 ft board covers 32 square feet; divide roof area by 32 and allow for waste.
Q: How is the board attached?
A: It can be mechanically fastened, installed in urethane adhesive, or set in hot asphalt per JM application guidelines.
Q: What R-value does 4.3 in. provide?
A: The JM data sheet lists an LTTR of 25.5 (hr-ft2-F)/BTU for the 4.3 in. thickness; actual R-value depends on installation conditions.
Q: Is it approved for direct steel deck application?
A: Yes, the closed-cell foam core is approved for direct application to steel decks.
Q: Does it qualify for JM guarantees?
A: ENRGY 3 is for use in approved JM Peak Advantage roofing guarantees.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
At 4.3 in. this board delivers a high LTTR of 25.5 per JM's published table, letting you hit demanding R-value targets with fewer layers. Note that thicker boards at 20 psi still need fasteners long enough to penetrate the deck properly, so verify fastener length with total assembly thickness. Keep the large 4x8 panels flat and dry on the deck and follow JM's pre-securement patterns under mechanically fastened membranes.
Large rigid boards catch wind easily before fastening; stage and secure panels promptly and follow manufacturer installation instructions and local code.
Order Johns Manville ENRGY 3 4.3 in. polyiso boards to maximize insulation value in your commercial roof.
All third party trademarks, including logos and icons, referenced on our website and product pages remain the property of their respective owners. Unless specifically identified as such, Arbor's use of third party trademarks does not indicate any relationship, affiliation, sponsorship, or endorsement between Arbor Home and the owners of these trademarks. Any references by Arbor Home to third party trademarks are to identify the corresponding third party goods.
