This has advantages and disadvantages and each of those should be weighed carefully.
Overlay shingles roof.
What you need power nailer or roofing hatchet tape measure roofing shovel or flat pry bar hammer drill carpenter s square straight cut tin snips utility knife chalkline broom.
That said overlaying asphalt shingles with a metal roof could be an option provided there is no underlying damage.
In general overlaying a new roof takes less time less labor and thus less money.
An overlay roof occurs when keep your existing roof as is choosing instead to shingle on top of it.
It s good to know that you can only choose this option if your roof has not been overlaid previously.
However this can only be done once.