Did You Know.............
Is your client concerned with multiple layers of shingles on a roof? Perhaps they should be and here is why.
Shingles weigh between 350-450 lbs per 100 square feet. Roofs are not typically designed to carry more than two layers of shingles. Evident by the bowing roof lines of some homes over 100 years old.
Many roof shingle manufacturers will not warranty their product over another layer of shingles. Shingles are designed to go down over bare plywood.
Multiple layers of roof shingles may mask a previous problem. Another layer of shingles is not going to fix the leak in the one below.
Many newly written building codes are starting to address the problem of multiple layers of roof shingles. Municipalities are seeing the problems that multiple layers of roof shingles can cause.
Although insurance companies do not have a specific limit to layers it is easy to see that the lower layer on a multiple layer roof could be 20 plus years old and a potential problem. If you have any questions or need a professional opinion please call or email me.