Steel shingles weigh about 1 4 what asphalt shingles weigh and aluminum shingles weigh about 1 8 what standard shingles weigh.
How to install metal roofing over shingle roof.
Installing the metal roofing over 1x4 s allows the ability to also install additional insulation under the metal roof.
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.
The metal used for the roof can be tin copper aluminum or steel.
Venting the eaves to vent the roof holes are cut in the old roof above the soffit which pulls air through the soffit vents underneath.
Make a slat board base on top of the shingles.
Installing metal roofing over shingles is the best solution.
Install your metal edging around the perimeter of your roof.
Use 1 1 4 inch.
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.
The vast majority of installations of the metal roofing systems produced by my company are over existing shingles.
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.
You will need to lay some 1 by 4 inch pine boards lengthwise every two feet on your roof.
Install the metal edging.
The low weight of metal roofing is one thing that encourages this.