TAR AND GRAVEL
Roofing systems constructed of hot asphalt and fiberglass roofing felts have proven themselves over the decades. Our typical four-ply roofs are fully guaranteed for 20 years and with general maintenance have a 35-to-40 year life expectancy.
We have installed hundreds of roofs in the 1950’s and 1960’s that are still water tight today. The generic “tar and gravel” term simply refers to the asphalt and gravel coating on top. An alternate coating at times is a smooth aluminite or a white polymer.
MODIFIED BITUMEN (APP & SBS)
Bitumen-type roofing systems are best applied on low-sloped roofs. Most manufacturers of bitumen roofs do not allow their installation on flat roofs that have any ponding water. Historically, bitumen roofs have not had a good life expectancy, especially on flat roofs.
No manufacturer of bitumen-type roofing warranties these products on residential roofing or re-roofing.
ALTERNATIVE SYSTEMS (Thermoplastic, Thermoset, Liquid Applied Foam, etc.)
There are numerous other types of roofing systems on the market. Typically, these systems have material components that the manufacturers change frequently. This prevents long-term observation and analysis.
The perennial question is “if these systems perform as claimed by the manufacturers, why are they continually changing the material components?” Many of these systems are difficult if not impossible to alter after they are installed. A simple roof penetration (as in bath remodel vents) are extremely difficult to waterproof to some roof systems.