Yavapai County Contractors Association
Q: We are in need of a new roof and, following your advice, we obtained three bids, requesting a separation of labor, material and product description. We also verified that tax was charged appropriately. Our question is: Subcontractor A quoted 15# underlayment, subcontractor B quoted 30# underlayment and subcontractor C quoted synthetic underlayment. Would you please walk us through the difference and what should we do? -Ernie and Donna, Prescott Valley
A: As defined by the International Building Code: [un∙der∙lay∙ment n.] - "One or more layers of felt, sheathing paper, nonbituminous saturated felt, or other approved material over which a steep-slope roofing covering is applied."
There is a multitude of material types, with felt being the most commonly used. There is no one-size-fits-all for the type of roofing underlayment, since the guidelines of underlayment pertain to the pitch of the roof, and the roofing material. Using an example of the most common type of roof material, which would be asphalt shingles, and the most common roof pitch of 4/12, the underlayment requirement is a 15# felt. Other types of roof covering and pitch will require increased poundage of underlayment. If the pitch of your roof is 4/12 or less, the 15# underlayment is per code, and it could be that Subcontractor B was just adding a second layer for "protection." There is not a huge cost difference for a double layer of felt versus a single layer.
Synthetic underlayment, which Subcontractor C quoted, can be used as long as it meets UL listing. There are advantages to using synthetic underlayment and, in talking with Dave Kinion of Central Basin Roofing and Greg Barstad of Granite Basin Roofing, they only use synthetic underlayment. Felt material serves a minimum purpose. Is it the best underlayment? No. Synthetic underlayment is engineered to withstand heat and precipitation for better and longer protection for your roof system. Synthetic underlayment has a much higher strength factor (it will not tear around nails and requires fewer nails to hold in place); is resistant to bugs, rot and fungus; and can remain exposed for extended periods such as 6 to 12 months without degradation. Synthetic is promoted to be a "premium" performance upgrade for an underlayment as compared to the traditional felt products and, yes, it does cost slightly more, but it has better performance and has a longer warranty.
The only question I would have pertaining to your quotes would be if your roof has a higher than 4/12 pitch, because if it does, you are required to have #30 felt vs. #15 pound and synthetic will work on both applications.
The Prescott Fire Department, Central Yavapai Fire Department and Chino Valley Fire Department are holding a series of public meetings for questions and answers pertaining to fire code changes. The meetings are 11:30 a.m. March 6, March 13 and March 27 in Prescott Council chambers.
Yavapai County Contractors Association (YCCA) is a professional association representing licensed, bonded and insured contractors, suppliers, distributors and business entities. Call YCCA for information on hiring a contractor at 778-0040. Submit questions to email@example.com or through www.ycca.org.