{"id":8344,"date":"2018-10-30T09:11:39","date_gmt":"2018-10-30T14:11:39","guid":{"rendered":"https:\/\/www.iko.com\/comm\/?p=8344"},"modified":"2025-08-12T14:12:03","modified_gmt":"2025-08-12T19:12:03","slug":"what-is-a-torch-down-roof","status":"publish","type":"post","link":"https:\/\/www.iko.com\/comm\/blog\/what-is-a-torch-down-roof\/","title":{"rendered":"What is a Torch Down Roof?"},"content":{"rendered":"

Torch down roofing (sometimes referred to as \u201ctorch on\u201d roofing) is so named because it requires an open-flame propane torch. In this installation method,\u00a0sheets of modified bitumen<\/a>\u00a0are rolled out onto the roof, and a roofing professional uses a hand-held propane torch to heat the material and adhere it to the surface. Once the layers reach the right temperature, seams are melted together to create a waterproof seal.<\/p>\n

\"roofers<\/p>\n

The membrane layers of a torch down roof are made of an asphalt compound called bitumen that is modified with either rubber or plastic. The main strength of this type of roofing is that it can expand and contract without melting or cracking. It has a high tolerance for both the heat and the cold it will experience on the roof during the change of seasons. There are different types of torch down roofing including two-layer and three-layer systems.<\/p>\n

\"roofer<\/p>\n

If you\u2019re wondering whether torch down roofing is the right choice for your flat roof, you can learn about the pros and cons of torch down roofing from this article. We\u2019ll also cover the details of the materials and layers that are used to create a torch down roof.<\/p>\n

Torch Down Roofing Materials<\/h2>\n

You may have heard a reference to a torch down roof as a \u201crubberoid\u201d roof (implying the material contains rubber), but that may not be accurate. All torch down roofing is made from modified bitumen, or bitumen with additives. Bitumen is made from asphalt, a tough material that is used in many roofing applications. Manufacturing torch down roofing requires modifying or mixing the bitumen with a polymer.<\/p>\n

\"the<\/p>\n

The first polymer used for this purpose is Atactic Polypropylene (APP), which is a form of plastic, not rubber. APP torch down roofing membranes are flexible and respond well to both heating and cooling.<\/p>\n

\"the<\/p>\n

Another polymer added to create modified bitumen roofing material is Styrene Butadiene Styrene (SBS) modified bitumen. As a form of rubber, SBS also makes the bitumen flexible and has a lower melting point than APP.\u00a0SBS modified bitumen roofing membranes<\/a>\u00a0can be installed by torch application, but are also\u00a0self-adhered<\/a>,\u00a0cold-processed<\/a>, or applied with a mop.<\/p>\n

A mat of fiberglass, polyester, or other material is often used as a sturdy core for torch down roofing membranes. Manufacturers also may embed small granules into\u00a0the top of the membrane to add fire resistance<\/a>, color options, ultraviolet (UV) radiation protection, or other distinctive characteristics.<\/p>\n

Types of Torch Down Roofing<\/h2>\n

\"commercial<\/p>\n

There are two main types of torch down roll roofing: two-layer systems and three-layer systems. Both systems have a base and cap sheet, but in the three-layer system, the roofing professional will apply a\u00a0base sheet<\/a>, then a smooth cap sheet, and finish with a granule cap sheet. This extra layer helps extend the life of the roof and usually enhances fire resistance, energy efficiency, color, or other features.<\/p>\n

Components of Torch Down Roofing Systems<\/h2>\n

\"Components<\/p>\n