Modified Bitumen Roofing

Commercial Roofing Contractor Serving Bradenton and Sarasota

Modified bitumen roofs are a popular choice in the commercial roofing industry for their long useful life, versatility and inherent resistance to damage of all kinds.

Modified bitumen is a roofing membrane made from asphalt mixed with thermoplastic polymer with reinforcing layers of polyester or glass-fiber fabric, with embedded granular ceramics as the top layer. The addition of thermoplastic polymer in the mix allows the asphalt to take on a plastic-like quality that helps to increase the UV resistance and waterproofing abilities of the roof membrane.

Benefits of Modified Bitumen Roofs

Modified bitumen membranes can be applied in multiple layers, similar to a built-up roof (BUR), but a single-ply application has many advantages on its own.

Cost-efficient As one of the lowest-priced roofing materials in the commercial roofing industry, modified bitumen is also easy to apply, which saves on installation costs.
Energy-efficient The top layer of a modified bitumen roofing system can become more energy efficient through roof treatments that add reflectivity properties. Adding UV resistance helps conserve the energy used by the building’s HVAC system, leading to potentially lower energy bills.
Fire-resistant The composition materials of modified bitumen are inherently fire resistant. This means that the roof is safer and could result in insurance premium savings.
Flexible Modified bitumen’s flexibility makes it versatile enough to endure temperature fluctuations without cracking or becoming compromised. The material can expand with the heat and contract with the cold and not lose its shape.
Low maintenance Properly installed, modified bitumen roofing doesn’t typically require much maintenance. If the time comes in which the roof is damaged, many repairs can be quickly executed with bitumen patches. Though the useful life of modified bitumen can top 40 years, it may be prudent to have coatings applied at around the 20-year mark to extend the life of the roof.
Tear-resistant One of the main benefits of modified bitumen roofing is that it is highly resistant to ripping and tearing. This feature is accomplished due to the reinforcing layers. Resistance to tearing is important for low-slope commercial roofs, especially those that see any amount of foot traffic.
Waterproof Bitumen’s composition makes it inherently waterproof; layering it can create one of the most waterproof commercial roofing material available.
Wind-resistant The strength afforded to modified bitumen roofs by its tough reinforcing layers allows the roof to stand up to high winds, hail and other extreme weather conditions.

Framework & Applications

Modified bitumen is a five-layer composition made of the following components:

1. Insulation, typically polyiso, composite boards or coated glass panels, provides both R-value and a stable substrate for the roofing system
2. Modified base sheets reinforce the base in preparation for the membrane application
3. Modified bitumen membranes are fabricated sheets composed of co-polymer bitumen reinforced with polyester or fiberglass
4. Adhesive provides waterproofing between the layers of the modified bitumen roof
5. Surfacing made from silica, ceramic coated granules or other materials provides reflectivity for UV protection and protection from weather conditions

modified bitumen roofing company in bradenton and sarasota

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If you are in need of a knowledgeable roofing contractor that specializes in modified bitumen roofs, the industry-leading team at AKVM can help. We offer competitive pricing, financing options, and free in-person evaluations and quotes. Contact us with any questions you may have, we will be happy to assist you.

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Developed in the 1960s in Europe specifically for flat or low-slope roofs, modified bitumen is designed to withstand temperature fluctuations and foot traffic without tearing, lifting or cracking and can be installed over the top of an old roof if certain conditions are met, eliminating the tear-off step. The step-by-step installation process is as follows:

It must be noted that the following torch-down method of installation for modified bitumen roofing should only be performed by a qualified roofer, as the process can be dangerous.

1. The roof is cleared of any debris or dirt build-up.
2. Heavy roofing felt is nailed to the decking or insulation in preparation for the membrane.
3. The drip edge and flashings are installed and primed with adhesive.
4. Sheets of roofing membrane are rolled out and cut, with a few inches of overhang allowed to remain.
5. The roofing membrane is adjusted to ensure the proper overhang as well as smoothing the membrane to a perfectly flat surface.
6. The roofing membrane is then re-rolled tightly about halfway.
7. Seams are sealed using a cold-applied adhesive (aka solvent-welding) and a squeegee is used to properly seal the adhered seams together.
8. This process is repeated, overlapping the edges of the sheets.
9. The new seam is pressed tight using a foot or gloved hand to ensure a tight seal.
10. The process is repeated until the entire roof is covered and sealed.
11. The roof must remain undisturbed for the duration of the setting process, as foot traffic could displace the adhesive and compromise the waterproof seals.

The cold-adhesive application method is outlined here, but modified bitumen can also be installed by using a self-adhering sheet, making the installation even easier for the roofers and saving you labor costs. Cold-process adhesive methods do not give off chemical fumes during or after application. In some areas at risk of experiencing high winds, mechanical fasteners are used to create the strongest wind resistance.