Metal Roof On Top Of Asphalt Shingles

3 install 1x4 purlins down over the shingles before installing the metal roof the third way to install a metal roof over shingles is by applying 1x4 purlins over the shingle roof.

Metal roof on top of asphalt shingles.

Most codes now allow no more than two layers of roofing before requiring a complete tear off. Things to know about metal over shingle roof problems. Metal roof over shingles condensation. After all you ll be making a significant and long term investment.

This method has its benefits as well. Put the steel down directly on a vapor barrier. Metal roofs must be laid flat on a vapor barrier because steel will condensate if there s any air space underneath it. The second way to install a metal roof over a shingle roof is with the use of purlins or battens.

Both metal and shingle roofs are great options for your next roofing project. The purlins are screwed or nailed down to the roof deck depending on how the metal roofing manufacture has testing for their roofing panels and then the metal is installed to the purlins. It is very much like constructing a non loadbearing interior wall framework and sticking that framework on top of your roof. As long as the plywood under the shingle roof is in good condition this way can provide many benefits.

This is by far the most common way to install a metal roof. Can you avoid tearing off your old asphalt shingle roof by putting a steel roof over it. It doesn t matter if the air space is a half inch or six inches because the condensation factor will remain the same.