No Sheathing Under Metal Roof

If your home s existing shingles are pretty curled you could install a textured metal roof such as a metal shingle shake or tile directly over the curled shingles along with underlayment.

No sheathing under metal roof.

Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes. You also could install a corrugated through fastened metal roofing product and probably not have issues. How to prevent condensation under a metal roof. Owners of agricultural buildings man caves and horse barns all are worried about the corrosive effects of condensation.

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. Mike the pole barn guru. Underlayment must also act as a secondary weather barrier in case the roof fails. This would mean a plywood deck with some sort of building paper to handle the inevitable condensation that forms on the underside of the roofing.

The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. 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. The best underlayment for metal roofs. In order to add moisture barrier under metal roof you can spray the undersides of the roof by using a thick layer of polyurethane spray foam.

For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. Traditionally metal roofs have used standard 30 pound felt paper underlayment. Polyurethane spray foam metal roof insulation. My understanding is that with metal roofing you absolutely have to have a drainage plain.

July 28 2017.