The old shingles become a layer that can foster mildew growth and trap layers of moisture.
How many layers of shingles are allowed on a roof in kentucky.
This will also be constrained by other factors.
In some instances 3 layers may be allowed but this is rare.
However this depends upon the roof materials.
That limit pertains to roofs with up to a 4 12 pitch.
Adding a second or third layer of shingles adds significant weight to the structure.
Generally it is fine to have three layers of shingle codes but you should check this is the case with your local building permit people and you should make sure that your roof and the rest of the structure have the strength to cope with the extra weight.
In some situations depending on type of material and assembly the code does not allow any layers of existing roofing materials to remain under new roof covering.
So how many layers of roof shingles are allowed.
Finally consider whether reroofing over the.
The soundness of the building you re re roofing is another consideration.
There are important reasons why this code is in effect.
The contractor may do a walk on the roof and also inspect from the attic for any rot before installing a second layer of shingles.
For example cedar or tile roofs are only allowed one layer.
New roof covering materials are generally allowed to cover only one layer of existing roofing material.
In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition.
Some home insurance policies will not cover roof repairs that include multiple layers of shingles.
Most building codes allow up to two layers of organic or fiberglass asphalt shingles.
Regulations allow a maximum of two layers of shingles on a roof but experts say you shouldn t lay asphalt shingles over an existing roof.
When it s time to replace your roof there are several factors that might lead your roofing professional to recommend adding shingles on top of your existing layers.
Most areas only allow for a maximum of two layers.