Osb Under Metal Roof

1 metal 2 air space of 3 4 or greater using 1x4 or 2x4 purlins 3 wrb and 4 5 8 to 3 4 of ply or osb.

Osb under metal roof.

Underlayment must also act as a secondary weather barrier in case the roof fails. 1 some metal roofs will be more likely than others to telegraph any unevenness of the surface beneath them. Metal roofing roofing answers roofing installation roofing materials oriented strand board commonly referred to as osb is a type of engineered lumber similar to particle board formed by adding adhesives and then compressing layers of wood strands. Then the top of all your purlins once osb under metal roof panels is placed will be in the same plane and the roof steel will lay flat.

Cross purlin designs with 16 oc are sometimes called for. April 3 2017 filed under. Traditionally metal roofs have used standard 30 pound felt paper underlayment. Metal should be installed using a cold roof design so the typical metal assembly would be.

This case is most certainly the exception to the general rule and happens in far less than 5 of all post frame buildings. Allen a couple of things to consider. You can test fastener pull out resistance. In order to avoid a hump at the transition from two layers of materials to one the notation on the building plans advises to lower the roof purlins in these areas by 7 16.

Osb is widely used as roof decking material. The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. The best underlayment for metal roofs. Screws will do better than nails.