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ASAP Commercial Roofing


Modified bitumen roofing is a type of membrane roofing, and an evolution of asphalt roofing materials.

It is made from asphalt and rubber modifiers and solvent. The modifiers and solvent are used to replace plasticizers. The bitumen contains fiberglass or polyester fiber matting to increase durability.

The most commonly used types are SBS and APP. SBS stands for “styrene-butadiene-styrene” and it increases the material’s flexibility. This makes the material stronger, more durable, and able to expand and contract through the weather.

The other type is APP, which stands for “attactic polypropylen.” APP is best for a longer-lasting roof. However, SBS tends to be the more popular of the two, due to the material’s flexibility. This type of roof can generally only be used on flat roofs, or roofs with low slopes.

Modified bitumen roofing is installed in multiple plies. In a traditional installation, each of these plies are torched together, normally at every ¼ turn of the roll. It is also an option to use a cold adhesive, though it is advised that the torching method is used.

Since the materials are torched together, this creates a watertight roof, which more consistently protects your building from the weather. This method must be completed by a professional, as it is a more difficult installation.

There are a couple cons to modified bitumen roofing. This type of installment definitely requires a professional to complete the task. In a traditional installation, torch-down, extreme heat is needed to properly weld the layers of material together, meaning a torch is required. If done improperly, it is possible the roof could catch on fire.

The advantages of mod bit however, seem to outweigh what is negative. For example, there is good uniformity of the roofing system, when done by a professional. Consistent thickness is used and there is tight quality control.

Due to the easy expanding and contracting of the material, it can handle high and low temperatures. It is tear resistant, because there are more layers to it than most roofs. Modified bitumen is weather resistant, and water tight, due to the welding done during installation.

A ModBit roof is also easy to repair in case it does rip; bitumen patches are available to quickly patch up the roof. This roof is also energy efficient, as a “cooling layer” can be added to the top layer, protecting your building from extreme heat, and lowering your cooling bills in the summer.

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