There are many ways to handle your roof replacement. A lot of commercial and residential flat roof owners know that you can install a new roof over top of an old one. Many old built-up roofs are still out there, and most even have rocks on them. These roofs can be expensive to tear off and dispose of, so for years roofers have been overlaying with “recovery” insulation board and single – ply roof systems such as TPO membrane, E.P.D.M., modified bitumen membrane, and P.V.C. membrane. These roof systems will last about 20 years and then you tear both roof layers off and start over.
Single-Ply roof systems are also roofed over. Building codes only allow for two layers of roofing and we agree with this code. Also, the insulation and roof deck on your existing roof must be dry and in such a certain condition to be roofed over. Some roofs cannot be left in place and roofed over for several reasons, so consult with a roofing professional to see if it is an option.
Special specifications are made by the industry when roofing over, so be sure you can trust and rely on your roofer to do the job correctly. Generally, it is better to tear off the old roof, but in many cases a roof over is a very acceptable option. In fact, based on my experience, the vast majority of one layer flat roofs get a retro-fit treatment.
Call or email me if you want to talk about it. Thanks for reading.
Robert Andrews, II