Johns Manville Formaldehyde-free fiberglass rolls are for use in 2' x 6' exterior sidewalls, basement walls, garage walls, floors and ceilings/attics. Because they are friction fit no staples are needed. Use of a separate vapor barrier may be required. They help save energy and provide good sound absorption. Glass fiber will not settle rot, mildew or deteriorate. Rolls can be cut to any length. This product has been GREENGUARD® certified for superior indoor air quality.