Man on roof installing torch down roofing in Portland OR, Bend OR, and Vancouver WA areas

Modified bitumen roofing, commonly referred to as torch down roofing, is a fantastic option if you have a flat or low pitch structure. American Mastercraft has been serving the Portland OR, Bend OR, and Vancouver WA areas for over 30 years. With these decades of experience come the expertise in many roofing types, including which would be best for your structure. Torch down roofing is a durable and long-lasting roofing material, specifically creates for those flat surfaces. Modified bitumen is a type of asphalt that has been modified with polymer additives to increase durability and weather resistance.

Types of Torch Down Roofing

Torch down roofing earned its name due to the installation process requiring the heat of a torch or open flame applied to the overlapping areas of the rolled roofing, thereby sealing it. There are two main types of torch down to choose from, depending on your roofing needs: two-layer system or three-layer system. Two-layer systems consist of a base sheet and a smooth cap sheet. A three-layer system adds an extra layer of granulated cap sheet for the added benefits of: 

  • Extending the life of the roof 
  • Adding color 
  • Increased energy efficiency  
  • Increased fire resistance 
  • Ultraviolet (UV) radiation protection 

Benefits of Torch Down Roofing

There are many features of torch down roofing that make it the best option for flat or low pitch roofs. 

  • Flexibility: Designed for all climates, the flexibility of the added polymers allows the modified bitumen to expand and contract even in extreme hot or cold weather.  
  • Thickness: One sheet of torch down is up to three times thicker than the average PVC flat roofing system. This makes torch down significantly more resistant to puncturing or snow collapse. 
  • Solves Condensation: You may think that a light-colored roof is better due to the reflection of solar rays, but dark is better. As heat and cold collide, it creates condensation that will rot your roof. Dark torch down roofs are UV ray resistant and reheat in the sun, vaporizing the condensation, thereby preventing roof rot. 
  • Durability: Due to torch down’s resistance to water, UV rays, and puncture damage, this allows the modified bitumen roof to last for up to 20 years with minimal repairs. 

Asphalt Roof Installation and Maintenance Services

Modified bitumen comes in rolled sheets that are unrolled in multiple layers by a professional roofer and sealed with the heat of a propane roofing torch. Both two-layer and three-layer torch down are installed in the same manner:  

  • Insulation: Necessary to retain heat in the building, especially important for flat or low-slope roofs in cold climates. 
  • Vapor barrier: Helps prevent the roof from developing condensation or moisture damage.
  • Overlay board: This layer is important for supporting the bitumen membrane. There are a few material options for this layer, like fiberglass, that a professional must install to ensure it is level. If not level, the roof will experience “ponding” which is when water is collected – like little ponds – where the roof isn’t level. 
  • Base sheet: The first layer of torch down, this is used to secure the overlay board and is sealed with direct heat fusion, hot mopping, or adhesive.  
  • Cap sheet: In a two-layer system, the cap sheet is a smooth top layer that is rolled out by a professional. As it is unrolled, the professional will use a roofing torch to heat the bottom of the cap sheet and seal it to the base sheet. In a three-layer system, there is a smooth cap sheet and then a second granulated cap sheet applied in the same manner. 
  • Flashing: A self-adhering modified bitumen is then applied as a finishing touch to seal around features that penetrate the roof like vents or HVAC (heating or air conditioning) units. 

The roofing professionals with American Mastercraft specialize in many kinds of roofing, for new roofs or small repairs. Because of the inherent nature of torch down roofing installation, for safety purposes this roofing should be left to the professionals.

Your Partners in Torch Down Roofing

The professionals at American Mastercraft have over 30 years of experience serving the communities of Portland OR, Bend OR, and Vancouver WA. Known for providing exceptional craftsmanship, our dedication to quality at every stage means no detail is overlooked. If you have a flat or low-slope roof in need of repair or replacement, don’t hesitate to contact us today for a free estimate!