How Many Layers Of Roof Shingles Are Allowed

However this depends upon the roof materials.

How many layers of roof shingles are allowed.

Installing new roof shingles over old effectively doubles the weight of the roofing so you have to make sure your roof structure can handle the extra load. This roofing system has two layers of material. When replacement is required there will likely be an added expense in removal and disposal of the material it s not a deficiency so i just give an informational statement. 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.

On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. Most areas only allow for a maximum of two layers. This will also be constrained by other factors. Asphalt shingles typically can have one more layer added over the top two roofs total.

In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition. 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. Most building codes allow up to two layers of organic or fiberglass asphalt shingles. In some instances 3 layers may be allowed but this is rare.

For example cedar or tile roofs are only allowed one layer. That limit pertains to roofs with up to a 4 12 pitch. Steep sloped roof products such as tile slate metal and shakes only allow one layer. For many years it was acceptable to put even the third layer.

If the structure can support the added weight a typical 20 square 2 000 square foot reroof will cost at least 1 000 less than a tear off job. While this is acceptable under the florida building code it is the maximum number of layers allowable. That s also why building codes commonly limit re roofing to no more than two layers. A roofing contractor will know exactly how many layers of roof shingles are allowed in your area for your building but it is normal that you will be permitted up to three layers of shingles.