With a long life span and 25 year guarantee period, fibreglassing a flat roof can be very economical compared with the alternative, felt. While the process is quite straight forward, there is a high level of technical experience required. The whole process of renewing the roof doesn't have to be completed in a day, however the top coat should be laid within a day to achieve a seal. Therefore very large roofs, like the one shown below, can be fibreglassed, however it does require a great deal of experience. In addition any shape roof can be fibreglassed including a roof with a pitch. Below are a series of pictures, taken while renewing a roof at Texaco Oil refinery in Pembroke, demonstrating the process of fibreglassing a roof.
This process of flat roofing has been around for decades. It is a cheaper option of renewing a roof however, this process is labour intensive and therefore the differential between the two methods of flat roofing is somewhat less than it used to be. Renewing a felt roof can be done in less favourable weather than fibreglassing. The normal guarantee period of felt roofing is 10 years.