Which is best for an attic: closed or open cell spray foam?

— Karen Zebulon, NC

Answered by Matthew McCullough on February 22, 2011

Which one is better in the attic: cellulose or rigid foam board?

— Felix Laredo, TX

Answered by Randy Potter on January 27, 2011

The attic in our 2004 house has no insulation. Will spray foam irritate my asthma?

— Marie Richmond Hill, GA

Answered by Danny Kelly on December 2, 2010