Do you have to use wood strips on roof before metal roofing is applied?

Answer 1

Whether you have to use wood strips on metal roofing will depend on several things:

1. The type of metal roofing. Most types of metal roofing do not require wood strips although strips can be used. Other types must be placed on wood strips, and some types of metal roofing cannot be placed on wood strips.
2. Whether the metal roofing is going over an existing roof. if you are going over an existing shingle roof, you will need to put something between the existing roof and the metal roofing, such as wood strips or 30 lb felt.
3. Wind requirements. in general, your roof will be more wind resistant by going down over the solid decking vs. the wood strips, which will not be as wind resistant.
4. Ventilation. The use of wood strips will allow the panels to breath better, reducing the change of condensation (water droplets) building up on the bottom of the panels.
5. Straightening out the roof line. You can shim wood strips up to reduce and eliminate sag lines in the roof if your plywood is wavy, or uneven.

When installing the most popular 3' wide metal roofing, many contractors choose to install wood strips first, but in most cases, you don't have to.