Tear off Vs. Roof Over?
It is allowed to install a roof over the top of an existing roof. By doing so the current owner of the building can save some money on the roofing project. However, Roofing over another roof does not provide the same quality of roof, or offer the same level of security that a roof system installed when a complete removal was performed. This is where people say, “Building code, and manufacturers allow it. It must be all right.” Let’s look how the code officials, and manufacturers look at roof over jobs. When installing asphalt composite shingles most Building Codes allow for up to 2 layers of asphalt roofing on a structure. The code has nothing to do with shingle performance. It is written in regards to structure performance, and how much weight it can handle. Manufacturers also prohibit roofing over an old roof. However if you read the fine print of any roofing manufacturer’s warranty you will find verbiage in their warranty exclusions that say “We will not warrant product failure if r