Built-Up / Modified Bitumen Roof System Installation and Repair

What to Know About Built Up Roofing and Modified Bitumen Roofs

Choosing the best commercial roofing starts with knowing about available roof materials. Two of the most popular choices today are built up roofing and modified bitumen roofing. They sound the same, but there are some important differences between the two.

Built-Up Roofing System Installation

A built-up roofing system (BUR) is extremely durable, waterproof, and easy to maintain. These roofing systems are multi-ply meaning that they are installed in several layers:

• The first layer is typically rigid roof insulation.
• The insulation is then covered with a cover board and several layers of underlayment (tar paper) with asphalt between each layer.
• A cooling layer cap sheet or coating system goes on next.
• The roofing is finished with some type of stone.

The layers of roofing felt (tar paper) are saturated with the asphalt, creating a strong, water-resistant barrier. In most cases, even if the top layer is damaged in a heavy storm or suffers hail damage the lower layers of saturated roofing felt work to stop the water from entering the structure. Built-up roofing systems also provide fire protection, meeting the highest fire rating in the roofing industry.

Another advantage of built-up roofs is improved energy efficiency by deflecting UV rays. Business owners can earn LEED points by adding a white granulated cap sheet or aluminum coating for cooling.

Modified Bitumen Roof System Installation

Modified bitumen, or mod-bit, is a next generation cousin to a built-up roofing system. A modified bitumen commercial roofing system is made with roofing asphalt (bitumen) that's combined with a special rubber or plastic. The material is then reinforced further with fiberglass, creating a flexible waterproof membrane.

Mod-bit roofing comes in sheets that are installed in layers:

• First a base sheet is laid down.
• Then a cap sheet is placed over an insulating board.
• A cover board is placed over the insulation.

Once the roofing system is installed a roof coating or products with factory-applied coatings may be applied. The process creates roofing that is very durable yet flexible and easy to work with. Modified bitumen roofing comes with uniform strength and flexibility in a range of temperatures.

Newer installation techniques also allow these roofing systems to be installed without hot mopping, reducing the risks associated with fumes during installation.

Built-Up and Mod Bit Roof FAQs

• Why is modified bitumen roofing one of the most popular choices for a business in Austin, TX?

There are a lot of reasons why a business would decide a modified bitumen roof makes sense. For many commercial property owners, it comes down to value. Modified bitumen materials create a resilient roof that's cost effective to install, maintain and repair. These benefits alone are reason enough to choose modified bitumen for commercial roofing.

• How much does a mod-bit roofing system cost?

The cost is going to vary depending on how much material is used and the complexity of the install. Of course, the roofing company you choose to use will also be a huge factor in the overall cost. Typically, you can expect to pay between $4 and $12 per square foot for this type of roof system.

• How often should a modified bitumen roofing system be replaced?

These roofing systems are long lasting. They can easily last for 20-30 years, but in Austin it's possible for the lifespan to be 40 years or longer with regular maintenance. Since a modified bitumen roof does not require fasteners, there's a reduced risk of water, wind, or ice entering. This helps prevent premature wear and unnecessary damage.

These are among the most affordable, practical, and durable roofing systems for low-pitch or flat roofs. At LOA Construction, we install custom built-up roofing systems with professionalism, speed, and the best practices.

• What type of maintenance is involved with a modified bitumen commercial roof?

A modified bitumen commercial roof is durable, but even long lasting materials eventually wear out and can become damaged. Regular inspections once or twice a year are recommended to assess the condition of the roof and make repairs as needed. Leak repairs that are often needed after a storm or hail damage should be addressed immediately to avoid further issues.

Maintenance for a modified bitumen roof regularly involves checking for clogged drains, inspecting gutters, and looking for signs of damage to the roof. Water drainage off the roof will also be carefully evaluated to determine if repairs need to be made to prevent damage from pooling.

You may also need to apply another layer of top coating from time to time. This will ensure optimal energy efficiency and performance as the roof ages.

• How do I know if a built-up or modified bitumen roofing installation is right for my facility?

Choosing a roofing material is a big decision for a commercial property owner. Today, there are a lot of options for businesses in Austin, and each roofing system has unique pros and cons. Some of the top things to consider are the type of roof (sloped or flat), the size of the roof, how long you plan to own the property, how much foot traffic there is on the roof, and specific performance needs for the facility.

Is it time to replace your commercial building roof? Then let's get your roofing project started! LOA Construction can inspect your roof the same day. You'll get expert guidance regarding the type of roofing system that will work best for your building and your budget. It's the easiest way to know for sure if built-up roofing or a modified bitumen roof is an ideal option.