Make a slat board base on top of the shingles.
Installing metal roof directly over shingles.
Yes you can install a metal roof over shingles.
It provides a solid flat surface to attach the new metal roof to it creates an air gap between the back of the metal and the shingle roof which allows for airflow.
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.
How to install a metal roof over shingles hunker.
Best setting for installing a metal roof over shingles on tight budget.
Install over a framework of 2x2s.
First because the frame is screwed directly to the rafters and the interlocked shingles are screwed to the frame the roof can withstand.
This framework has three big advantages.
Install the metal edging.
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.
Can i install a new metal roof over shingles.
How to install a metal roof over shingles on a budget.
Another added benefit is that the layers of your old roof will further insulate your home.
Install your metal edging around the perimeter of your roof.
You will need to lay some 1 by 4 inch pine boards lengthwise every two feet on your roof.
In a standing seam roof long single panels run vertically all the way from the eave to the ridge.