Three Layer Felt Roofing Method

What is torch on roofing felt torch on roofing or torch down roofing as it is also known is a flat roof covering solution that involves three layers of modified bitumen felt melt welded onto the roof surface and each other with the use of a blowtorch to create an impenetrable waterproof seal.

Three layer felt roofing method.

Each of the three layers is laid in a half lap system so any joint in the roof is as far away as possible from another joint. Three layer felt systems have come a long way from the early days. Roofing felt is comprised of a base made from natural materials such as wood cellulose or synthetic ones such as fiberglass or polyester and then coated or saturated with a protective coating such as bitumen asphalt which repels water but still allows the product to breathe. These layers are all laid in a half lap manner so all the joints are the furthest away they can be from another joint.

Laying the first nailed layer of underlay felt. The products used today are a 3 layer membrane system applied with the use of a gas gun. Fitted using a blowtorch the 3 layer felt roof system benefits from being more stable than the older methods. An extra coating of sand or fine gravel can be added on top to improve the aesthetic appeal.

This layer is not bonded to the decking so that the decking can move without damaging the felt roof. Typically it s applied as a 3 layer system usually consisting of a perforated underlay a 2mm underlay layer then thick 4 5mm felt. Laying roofing felt this is then applied to a fibrous membrane which is typically made of fibreglass polyester or hessian. Showing the method of roll and pour on fixing felt onto a flat roof.

Showing the method of roll and pour on fixing felt onto a flat roof. In these kinds of felt roofs it is possible to fill low spots with two or three layers of felt applied with tar or another bitumen. Old style flat roofs were often designed with pieces of asphalt felt paper sandwiched between tar. Laying the second bonded layer of underlay felt.

Another method for fixing low spots is to apply new roofing plies to the problem spot. Installing any gutter drips. The two main methods of its application are pour roll and torch on. They are no longer laid with hot bitumen and have stone chippings put on top.