Shingle layers


#1

how many layers of shingle maximum can be put on a roof before its too heavy of a load? because i already have two layers on it, and don’t know if its ideal to put over the third layer.


#2

Depending on the city that you live in it could be 2 or 3. I dont suggest going over 2 layers and some of the manufacturers dont either. Best advise i can give you is to tear it off and it will last alot longer. A typical 2nd layer will only last half the life of a tear off so with 3 which is illgegal where i am could be even less. With a tear off it will last close to the warranty as long as the ventilation and installation is done correctly.


#3

Like gtp1003 stated, it is not wise to go over two layers. However, as far as the legality, it depends on where you live. I can tell you most places don’t want more than two layers of shingles on a roof, but will allow it if you get a structural engineer to sign off on the roof as being able to support the load of a third roof. Now, with that said, I don’t recommend installing a third shingle roof on a building let alone a second. I personally hate roof-overs, and always try to dissuade my clients from installing a new roof over a failing/failed roof.


#4

hello john doe,
if your goin to put a third layer on you may want to consider a 5 v crimp metal roof.
the third layer of shingles usually gets very lumpy and doesnt hold up as well/last as long. not to mention hard to get fastened well.

the metal roof can use the proper length of scew to secure all three roofs
very well, a good thing if your in high wind area.

5 v crimp metal roofs, performed the best in the hurricane hit areas i visited over the last ten years.

homestead, vero beach, punta gorda, the 5 v crimp was the only roof material that you would find not blown off.

good luck.

gweedo.