Metal Roof Underlayment Requirements

13 1 frequently asked questions.

Metal roof underlayment requirements.

We generally prefer the use of synthetic underlayment as it is more durable and will last longer. 11 plastic string reinforced poly sheeting best value roofing underlayment. Minimum thickness of the outside edge of plastic caps shall be 0 035 inch. This article series discusses roofing felt specifically addressing the roofing code or roofing manufacturer s requirements for use of an underlayment such as roofing felt tarpaper or other underlayment products beneath asphalt shingles and other.

Is roofing felt required. Make sure the product is designed to be used under metal. Underlayment must also act as a secondary weather barrier in case the roof fails. Underlayment shall be attached using metal or plastic cap nails or cap staples with a nominal cap diameter of not less than 1 inch.

How well roof underlayment performs will depend on which type you use. We recommend a polypropylene scrim reinforced underlayment made up of multiple layers. Roofing underlayment roofing felt requirements. Felt details for various roof slopes amp.

This type of underlayment is critical to a quality roof installation. Overhang the roof rake edge 1 5 and cover the underlayment with a metal rake edge trim. Traditionally metal roofs have used standard 30 pound felt paper underlayment. Synthetic roofing underlayment is to be laid horizontally parallel to eave with printed anti slip side up starting at the bottom of the lowest roof eave with a 1 5 underlayment overhang at the eave covering the pre installed eave drip edge.

Whether you re opting for a traditional underlayment or a selfadhered option the average life span of a metal underlayment will vary depending on the product that s selected. Metal caps shall have a thickness of at least 32 gage sheet metal. For architectural metal roof panel systems a roof underlayment is required to help control water leakage through the roofing system during heavy rain storms or under snow melting conditions. 12 roofing underlayment wind by mcm best roof underlayment for tile roofs.

Choosing the right roof underlayment. Becoming familiar with the metal roof underlayment options available can help you decide what s best for your commercial building. The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. At western states metal roofing we have been in the roofing industry for over 20 years and have encountered every type of scenario with both types of underlayment.