1 remove the shingles before installing the metal roof the first way to install a metal roof over shingles is by completely removing the old shingles before installing the new metal roof.
How to install metal roof panels over shingles.
Use 1 1 4 inch.
A benefit to doing it this way is that you can see if there is any rotten plywood that needs to be replaced before installing the new roof.
Steel shingles weigh about 1 4 what asphalt shingles weigh and aluminum shingles weigh about 1 8 what standard shingles weigh.
Put the steel down directly on a vapor barrier.
Install your metal edging around the perimeter of your roof.
The low weight of metal roofing is one thing that encourages this.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.
Metal roof over shingles condensation metal roofs must be laid flat on a vapor barrier because steel will condensate if there s any air space underneath it.
Work up from the initial row starting at the lower corner in a diagonal pattern staggering the shingles to prevent gaps.
Install the metal edging.
In a standing seam roof long single panels run vertically all the way from the eave to the ridge.
If you want to install steel over asphalt your best choice for installing metal roofing is to use a steel shingle system like the one shown instead of the more common and more expensive standing seam steel.
You will need to lay some 1 by 4 inch pine boards lengthwise every two feet on your roof.
It doesn t matter if the air space is a half inch or six inches because the condensation factor will remain the same.
The vast majority of installations of the metal roofing systems produced by my company are over existing shingles.