Torchdown
Often referred to as “2-ply” roofing, torchdown roofing is a flame activated bitumen-backed membrane installed over a fiberglass base sheet. The development of this product style has effectively pushed the “hot tar” roof systems out of use in the residential roofing industry. Its development allowed “pitched roof” contractors to compete for low-pitch or flat-roof installation without incurring the high cost of tar kettles or the equipment needed to get the tar to the roof. Torchdown is available in smooth and granulated styles and can be installed as a single-ply or dual-ply system. Although not technically a “torchdown” product, the self-adhering membranes are also sold in this product category. Some of the torchdown systems available are listed below:
| Style | UV Protective Coating | Manufacturer's Warranty (Years) | Functional Life Expectancy (Years) |
| Single-Ply, Smooth | Required | 10 | 10 |
| Single-Ply, Granulated | Not required | 10 | 10 |
| Dual-Ply, Self-Adhered | Not required | 10 | 10 - 15 |
| Dual-Ply, Granulated | Not required | 20 | 15 - 20 |
Pros
Ease of installation
Low cost
Low maintenance on granulated surface application
Cons
Open flame on roof
Ponding water limitations
Potential seam failure
High maintenance on smooth surface application
Limited life expectancy
