Roofing Underlayment

Peel-and-stick underlayment applied to the plywood roof deck during the installation of a standing seam metal roof.

"Tar paper" underlayment during the installation of an asphalt shingle roof.

Useful Links:

1. General: "The Use of Underlayment with Asphalt Shingles" explains why you use it. Available at the Canadian Asphalt Shingle Manufacturers' Association website.

2. Technical: "Grace Ice & Water Shield HT" is a product sheet worth taking a look at for information on this very popular underlayment. Includes product description, guidelines for use, and installation procedure. Available at Grace Construction Products.

3. A list of roofing underlayment manufacturers.