Asphalt shingles typically can have one more layer added over the top two roofs total.
How many layers of roof shingles are allowed in new york.
Although the new york state building code does allow for up to two layers of roof materials.
The soundness of the building you re re roofing is another consideration.
For example cedar or tile roofs are only allowed one layer.
First of all multiple layers of shingles simply means layering a new asphalt shingle roof on top of the old one rather than stripping the roof completely to expose the sheathing and replacing it with new shingles.
December 18 2019 by taylor made roofing signs that your roof has reached the end of its life are typically fairly obvious.
How many layers of shingles are allowed on a roof.
Consistent leaks shingle loss and mold growth can all point to the need for a new roof.
Steep sloped roof products such as tile slate metal and shakes only allow one layer.
On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.
Having the old shingles removed before the new shingles are.
Most building codes allow this but is it a good idea.
However this depends upon the roof materials.
Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio.
In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition.
But contractors who spoke with angie s list say best practices call for stripping the roof down to the wood deck to inspect it before installing a new roof.
Pros to overlaying a shingle roof.
Once you have discovered how many layers of roof shingles are allowed the next decision you should make is whether you will have the existing shingles completely removed to make way for two or three new layers or whether you will have another layer of shingles placed on top of the existing layer.
Now you just have to decide whether to remove the existing roof shingles or recover the roof.
Advantages of reroofing most building codes allow two layers of organic or fiberglass asphalt shingles on roofs with a 4 12 pitch or less and three layers on steeper roofs.
Any amount of short term savings you might see from a layover roof installation is not far outweighed by the longer term peace of mind that comes from knowing that the integrity of the decking has been confirmed.
Here are the pros and cons.