Using House Wrap Under Metal Roof Over Perlins

They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top.

Using house wrap under metal roof over perlins.

The roof is an important element of the building envelope. A building envelope is the physical separator between the conditioned and unconditioned environment of a building including the resistance to air water heat light and noise transfer. They give added support to the roof and also provide a nailing surface for the end panels and drip edge. For new construction florida building code does not require the use of a purlin system and some profiles like our tcm loc panel does not require use of purlins.

You will typically see purlins used for re roof project over existing shingles or other situations. Tips on installing purlins for your metal roofing project. In this case simply lay the insulation between the purlins. I ve seen instances where people have applied house wrap directly between roof purlins and roof steel in an effort to control condensation.

There are two ways to do this put in firring nailing though nails are not used any more for this strips or purlins in steel frame construction on the roof to support it or place the metal roofing directly on a flat surface like foam insulation board or the roof sheathing with roof water barrier in the correct position in the layer. Purlins are 2 by 4 feet and are installed much like metal roofing. House wrap is quite permeable. Taking care of your building envelope.

Can a metal roof be installed over my existing shingles without the use of battens. 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. It needs to be addressed with the utmost care and consideration. This great question comes from edward c a homeowner who plans to have a new metal roof installed over the aging existing shingles on his single story home.

Any warm moist air which would rise to it will pass through to the underside of the roof steel and condense. Thanks edward for allowing me to share our correspondence on this frequently asked question. Make sure that the insulation you are using is the same thickness so that the metal roof will fit better.