Underlay is used as part of torch applied roofing. The torch on underlay is designed for use beneath the top layer or capsheet and is designed to be melt-welded onto the roof surface with the rest of the torch applied roofing system.
What is torch on roofing underlay? A torch-on roofing system is designed specifically for flat roofs and contains three layers of felt (otherwise known as modified bitumen) that is then welded onto the roof surface to create a waterproof seal. Torch on underlay is one of the three layers that makes up torch applied roofing — felt, a capsheet, and a vapour control sheet. These three layers are required by roofing regulations, so the torch on underlay is a key component.
Do you torch on the underlay? Yes, the underlay is one of three components that make up the torch applied roofing system, so it is welded on using a blowtorch. Discover more about torch on roofing systems and the components, including capsheets, here at Roofstores.