Ask the Expert Question-and-Answer Archive

by Ron Joseph

December, 2004

Intumescent Paint

Q. Using intumescent paint, can I get a 1 hour rating on a steel bar joist/metal deck roof assembly?

I presume that you can get a 1 hour fire rating by using a qualified intumescent paint. I suggest that you visit the websites of several manufacturers of intumescent paint and select only those that have actually performed tests to demonstrate a 1-hour or longer fire rating.

Be aware that once you have applied the paint it must not come into contact with water, rain, etc., as the active ingredients might leach out of the coating rendering it less effective.

I strongly suggest that you insure that the product you select has been tested by the manufacturer for its fire rating. After all, if a fire should occur and the coating fails to provide the required performance, you will want to be able to present your insurance company with documentation to demonstrate that you used a certified product.

Best wishes,

Ron Joseph