Built-up roofing consists of two or three layers of bitumen sheet bonded together through adhesive or hot bitumen.The bitumen is produced through the distillation of crude oil.
Reinforced bitumen sheets are manufactured using a base layer consisting of one of a number of materials including organic fibres, glass fibre or bitumen-saturated polyester, though in practice, organic felts rarely meet performance criteria.
The material is passed through a bath of molten bitumen and then coated with sand to prevent adhesion.
Benefits of Felt Roofing:
Used for small outbuildings and Garages
Can be fitted in a day
The underlying structure is really important
The roof needs to have a slight gradient for water to run off
The timber (use wood not chipboard) joists underneath need to be strong to withstand any sagging of the felt over the years
Felt roofing with good preparation can last for many years
It is more economical than rubber and fibreglass