An unsealed roof deck allows up to 60% of the rain that falls to enter the attic.
A properly installed sealed roof deck can reduce water entry by as much as 95%.
Tape and Underlayment
Self-adhering polymer-modified bitumen flashing tape, applied directly to the roof deck to all horizontal and vertical joints in the roof deck; then underlayment or a reinforced synthetic underlayment over the entire roof deck. Specific tape, underlayment and fastening requirements may be found in the FORTIFIED standards.
Fully Adhered Layer
A full layer of self-adhering polymer-modified bitumen membrane (peel-and-stick) is installed over the entire roof deck.
Two Layers of Felt
Install two (2) layers of qualifying underlayment, overlapped on each other as specified in the FORTIFIED standards.
Install a closed-cell polyurethane spray foam applied to the underside of the roof sheathing at the joints between the sheathing panels and along all intersections between roof sheathing and all roof framing members.
Frequently Asked Questions
When is the best time to get a sealed roof deck?
The best time to seal your deck is when you’re re-roofing because there are more options and sealing the roof deck is most affordable when a new roof is being installed.
Can I seal the roof deck without replacing my roof?
Yes, in most cases, the roof deck can be sealed even if the roof covering is not being replaced. If the entire attic is accessible, closed-cell polyurethane spray foam can be applied to the underside of the roof sheathing from the attic. Spray foam insulation companies can usually install these products.
What do I tell my roofer?
Any roofer can install a qualified sealed roof deck system like those described on this page. Tell your roofer to review the information found on this page (see the links in the box on the right) and tell them to provide pricing for the system you prefer. You can also download and share the Roofing Checklist (see box above) with all of the roofers who are giving you pricing for your roof project.
Can I do more than just seal the roof deck?
Yes you can! Sealing the roof deck is a key part of a FORTIFIED Roof™. FORTIFIED Roof is a product of the Insurance Institute for Business & Home Safety (IBHS), a non-profit company, totally committed to preventing avoidable hardship, like family displacement and financial loss caused by severe weather.
IBHS has used more than 20-years of top-tier science to develop FORTIFIED Roof, a complete guide for keeping the roof system intact and water out. Learn more about FORTIFIED Roof.