Modified Bitumen Flat Roofs


Modified Bitumen Membrane (MBM) roofing is the most reliable, trouble-free and long lasting system available for flat or low slope roofs. It is made from asphalt modified with synthetic rubber which results in a very flexible product even in very cold temperatures. One that is highly resistant to cracking or breaking during roof expansion & contraction in temperature fluctuations. Modified Bitumen Membrane is easy to work with, especially in making alterations to a roof, like when retro-fitting curbs, HVACs, vents, plumbing stacks, skylights, etc. An added bonus is that there are no smelly fumes involved in its application as there are in tar and gravel roofing. Available in many colours, this ceramic stone-coated product is ideal for both residential and commercial applications. Modified Bitumen Membrane was developed in 1908, it is today the most common type of flat roofing application.

The procedure usually involves layering 2 plies of modified bitumen membrane, plus a reinforcement layer in key transition areas, and welding them together to form a completely sealed system that has no flaws. The base sheet can either be nailed, screwed, glued, welded, or mopped in hot asphalt, depending on the nature of the substrate and whether insulation is to be added to the system. The cap sheet is usually welded onto the base sheet, but there are also applications in which it can be glued, mopped in hot asphalt, or come as a peel & stick membrane.

The fact that the tiny granules of coloured stone are embedded in the cap sheet to protect from UV rays degrading the asphalt is a huge advantage over traditional tar and gravel systems. The latter normally cannot be continuously carried up parapet walls, curbs, boxes, etc., whereas the MBM is ideal for application from the flat roof and right up vertical surfaces. There is no limit to the height it can be applied. This is a major improvement over tar and gravel which can only go up a few inches and then must be covered with metal. Additionally, Modified Bitumen Membranes typically have double the life expectancy and much higher manufacturer warranties than most other types of flat roofing products. Rooftek is a manufacturer trained and certified installer of MBM membranes. Our very experienced Foremen are actually partners in the company, so we achieve that extra level of care in the application of such flat roofing systems.