Do I have to remove the asphalt shingles from my roof before I install a steel one?

Q:

Do I have to remove the asphalt shingles from my roof before I install a steel one?

A:

It is recommended that you remove the existing asphalt shingles from your home before you install any new kind of roofing on it. The reasons are as follows;

• Asphalt shingles are heavy, adding more roofing material on top of this can add to the weight and might cause problems over time it any snow where to sit on it.
• Nails or screws from the old roofing can work themselves loose overtime or with the changing temperatures and come in contract with the new roof. This could lead to a damaging of the new roof.
• It can be difficult to get the steel in straight and level going over existing asphalt, care has to be taken when installing the strapping and new material.
• You don't get the full picture of the roof sub structure so won't know if there is any damage or rot that requires fixing. 

Even though it is recommended that you remove them that doesn't mean that you have too. When you install a steel roof you usually have to strap the roof over the roof deck to create and air space to help the roof ventilate or breath. This strapping can be done over top of existing asphalt shingles, this give you the air space needed and also keeps the steel roofing from sitting directly against the old roofing.

Steel roofing also sheds snow rather well so that there shouldn't be that much weight from snow loads over the winter, this will help negate the concern for the extra weight added from not removing the asphalt shingles.

New steel comes in one piece so that it runs without a seam from the ridge to the eave, this helps strengthen the roof and has less places for leakage.

Sometimes there is no way around it you have to leave the existing shingles on; budget, customer preference whatever the reason it can be done.

Rob Abbott
Village Builders Inc.