Spray on Class II Vapor Retarder, Thermal Barrier, Ignition Barrier Intumescent Paint
Intumescent fire protection and vapor retarder coating for interior spaces over spray polyurethane foam.
Product Overview
No-Burn® ThB Spray Seal ™ is an intumescent coating for use over open and closed cell spray polyurethane foam as a Class II vapor retarder, thermal barrier, and ignition barrier in one application. Durability features also include exposure to UV and weather for up to 6 months. Compliant with the International Building Code and International Residential Code.
Higher R-value requirements in building codes are making it more and more difficult to achieve the needed values with traditional insulation methods. To achieve this, SPF insulation is becoming more popular for builders and homeowners alike.
In the International Energy Conservation Code (IECC) Climate Zones 4B, 5, 6, 7 and 8, high density closed cell spray foam qualifies as a Class II vapor retarder at 1.5”. Low density open cell spray foam can be utilized with an interior vapor retarder to control condensation, such as a spray-applied vapor retarder paint like No-Burn ThB Spray SealTM.
Unvented conditioned attics can be constructed by installing low density open cell or high density closed cell spray foam directly to the underside of the roof deck. Both foam types work in all climates. In IECC Climate Zones 5 and higher low density open cell spray foam can be utilized with an interior vapor retarder (Class II) to control condensation. This interior vapor retarder should be a spray applied vapor retarder such as No-Burn ThB Spray Seal (Figure 2). Note that in many jurisdictions a thermal and ignition barrier coating may also be required. No-Burn ThB Spray Seal also satisfies this requirement.
Joseph Lstiburek, Ph.D., P.Eng., Building Science Corporation
Contact us to learn how No-Burn can help meet your project specifications.
