This method has its benefits as well.
Installing metal roofing on top of shingles.
Building officials in some areas will only allow a re roof over one layer of shingles while officials in other places may allow you to place the roof over two layers of shingles.
Use 1 1 4 inch.
How to install a metal roof over shingles.
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.
Make a slat board base on top of the shingles.
However you ll want to check with your local building department before you make any decisions.
Install your metal edging around the perimeter of your roof.
This is by far the most common way to install a metal roof.
You will need to lay some 1 by 4 inch pine boards lengthwise every two feet on your roof.
The metal used for the roof can be tin copper aluminum or steel.
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.
In terms of performance many homeowners choose a steel roof making it the most popular option when it comes to creating a metal roof over existing shingles.
Steel shingles weigh about 1 4 what asphalt shingles weigh and aluminum shingles weigh about 1 8 what standard shingles weigh.
Install the metal edging.
Most metal shingles will be attached to the roof using metal shingle.
I would say that in most cases less weight is being added to the home by the new metal roof than what the current shingles have lost due to granule wear and oil evaporation.
The second way to install a metal roof over a shingle roof is with the use of purlins or battens.
As long as the plywood under the shingle roof is in good condition this way can provide many benefits.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.