Disadvantages of metal roofs.
Can u put metal roofing over shingles.
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.
Otherwise you will need to remove the shingles.
Some contractors feel that there is a problem with too much weight causing stress on the roof trusses and that condensation could be an issue.
On has the metal expands and contracts due to weather changes the metal will actually move.
Asphalt shingles can weigh up to four pounds per square foot depending on the brand.
Installing a metal roof over shingles can also result in an increased chance of trapped water vapor and moisture between the new roof and old roof resulting in new mold and rot.
However you can install metal roofing over the asphalt shingles but vice versa is not recommended.
As you can imagine there are a lot of differing opinions on whether it is permissible to put metal over the top of other roofing materials.
By placing metal roofing over shingles you can save in the labor costs of ripping them off while also preventing them from being thrown into landfills.
Metal roofing weighs less than one pound per square foot.
Metal roofs over shingles will also provide an extra layer covering your home helping to further insulate it.
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.
A metal roof is an alternative to a shingle covered roof but a metal roof can actually be installed over shingles.
This method has its benefits as well.
Can you avoid tearing off your old asphalt shingle roof by putting a steel roof over it.
Can you put metal roof over shingles the reason why this is important is because a shingle roof is granulated very similar to sandpaper.
Can you put steel roofing over asphalt.
Besides the necessary roofing skills you will need to learn tips specific to shingles installation.
In some areas building officials only allow a re roof over one layer of shingles.
The purlins are screwed or nailed down to the roof deck depending on how the metal roofing manufacturer has testing for their roofing panels and then the metal is installed to the purlins.
However you should only install a metal roof over shingles if you have less than four layers of shingles on the roof.
If you don t want to take our word for it check with your local building department.
So if your roof has two layers it may require a complete tear off even though steel is lighter than asphalt.
Most codes now allow no more than two layers of roofing before requiring a complete tear off.
