Flat roofs for commercial housing.

Flat roofs for commercial housing or apartment buildings in cities are an expanding market and new technologies are sprouting up. Though if you look closely it’s generally the same process.


Some applications are much lighter than others and tend to work well in non-industrial settings. Rooftop Designs has the highest CertainTeed certification available, putting us in the top 1% of all roofing contractors nationwide.

Modified Bitumen Roofing

Modified Bitumen Roofing or MBR is a thin membrane-like roofing application. Bitumen is defined as a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation. It is used for road surfacing and roofing. (Def. from Oxford Languages)  Bitumen is slightly different from Asphalt.

The Modified Bitumen Roofing process starts with a deck to hold the insulation, then placed over top is the modified bitumen rolled layer. Depending on the type of MBR the side that is touching the building will adhere either with glue or some heating process. Below is an overview of the installation process in more detail

Installing MBR

  1. Always check the weather. You’ll need dry conditions
  2. Gather all necessary safety gear and then check the structure to see if it can handle the roofing application.
  3. Next, you’ll need to prep the surface. Clean and remove all debris and dust and make sure your deck is dry. Use an asphalt primer on concrete decks first before the base layer
  4. A base sheet is then applied. This layer is generally fastened down mechanically with nails or washers and must be overlapped to provide for a better seal. This is very much like underlayment on sloped roofing applications.
  5. Then insulation is added. What type of insulation you use can change your final steps of adding the capping layer or the actual roll of MBR. Make sure to reference the installation guide and manufacturer's notes for any specifics.
  6. Next is the MBR layer. This MBR layer can either be glued down or torched with a blow torch to activate the seal.


Certainteed is known for its high-quality roofing materials. Rooftop Designs likes to give the best service possible. Certainteed’s Flintlastic MBR will last your building a long time with warranties lasting up to 25 years. Give Rooftop Designs a call today to get a professional to help you with your roofing and roof replacement needs.