Modified Bitumen Roofing: Everything You Need To Know
Find Out What Makes Modified Bitumen A Great Flat Roofing Choice, How We Install It And More In Our Tell All Guide.
FREE CONTACTLESS ROOF INSPECTIONS
Get A Free Estimate
Let's Talk About Modified Bitumen Roofing
Flat roofs, a traditional go-to choice for commercial buildings, are gaining popularity in the residential sector as well. Flat roofs offer easier maintenance, greater versatility, and higher energy efficiency than sloped roofs. Often, contractors recommend modified bitumen (mod bit) as an optimal flat roofing choice. What exactly is modified bitumen, what are its pros and cons, and how long does it last? The experts at Maxx Roof LLC have the answers.
What Is Modified Bitumen Roofing?
Modified bitumen roofing has evolved from the traditional BUR (built-up roofing) systems. The modern sheet roll packaging of modified bitumen makes it easy to transport and install. Thanks to the layered structure of this asphalt-based roofing material, roofs made from modified bitumen are highly durable, insulating, and water-resistant.
A mod bit roof is a five-layer system that consists of the following:
- Structural deck
- Asphalt emulsion base sheet
- Polyester/fiberglass reinforcing fabric
- Base coat
- Top coat
The two common mod bit roofing materials are SBS (styrene-butadiene-styrene) and APP (atactic polypropylene). The two options involve different installation techniques but yield largely the same results.
Modified Bitumen vs. Other Flat Roof Types
Apart from modified bitumen, two common types of flat roofing are the old-school BUR (built-up roof) and EPDM (rubber membrane roof). BUR roofs use alternating layers of bitumen and reinforcing fabric, topped with a stone or gravel layer. They are affordable but very heavy and difficult to install. EPDM is a sturdy single-ply roofing material, light and easy to install and repair. However, EPDM is highly puncture-prone, tends to absorb heat, and costs more than mod bit. PVC roofing is another popular option if you are looking for a light colored roofing material that can reflect sunlight.
Modified Bitumen Roofing Installation
Modified bitumen roofers use two main installation methods: torch-down (hot) or adhesive backing (cold), depending on the type of bitumen: SBS or APP.
- APP: APP installation uses the high-heat torch-down method. APP melts easily and cools directly on the base roof layer. The result is a hard plastic-like membrane with high resilience and superior waterproofing qualities.
- SBS: The rubbery nature of SBS allows for cold adhesive back sheet installation. The finished product is flexible and puncture-resistant.
In a hot mod bit installation, the roofing contractors roll out the bitumen sheets, making sure they overlap and cover the entire roof surface. As the contractor rolls out the sheet, he will apply high heat with a torch, making the bitumen melt and stick. This high-heat method of bitumen installation is hazardous and requires expert work with careful precautions.
Adhesive Back Sheet Installation
During cold installation, the contractor will carefully peel the adhesive film and roll out the bitumen sheet. The next step is smoothing out the sheets with a weighted roller, especially in overlap areas. The contractor will seal the edges with roofing cement as necessary.
The weather is a crucial element in cold mod bit installations. The optimal temperature range is 50-100F, which can be a problem during the winter months. Additionally, it is important to store the bitumen sheets in a warm place before installation to preserve their flexible, pliable nature.
APP vs. SBS: Which Is Better?
Both APP and SBS Modified Bitumen roofing systems have their pros and cons. APP is more resistant to UV radiation, while SBS is more flexible. SBS is easier, quicker, and safer to install. APP sheets may shrink over time, causing leaks, while SBS typically endures longer. After inspecting your roof, the expert contractors of Maxx Roof LLC will recommend a roofing material based on your roof size, budget, and other factors.
Lifespan Of Modified Bitumen Roofing
When choosing a roofing system, one of the first questions customers ask is usually “How long will my new roof last?” With proper upkeep, modified bitumen systems can endure 20+ years, depending on factors such as:
- The building’s location(ie: weather)
- Architectural design
- Installation quality
- Roof maintenance
Installation quality is a key factor for a long-lasting roof. An unprofessionally installed roof can lead to water pooling, which may cause weight imbalance, leaks, and structural damage to the building. To avoid such aggravations down the road, choose a reputable local contractor like Maxx Roof LLC. We stand behind our work on all projects, big or small.
Modified Bitumen Roofing Costs
Modified bitumen roofing system costs vary depending on several elements, including:
- The quality of installation materials
- The size of the roof
- Roof accessibility
- Installation complexity
- Seasonal pricing discounts
We can’t put an exact number on what your roof will cost to replace as there are too many variables at hand, however we would be happy to come out to your property and give you a complimentary estimate after we have inspected your roof. Once a full inspection has been done, then we can gather all the information needed to perform an accurate estimate for your modified bitumen roof.
Advantages Of Modified Bitumen Roofing
Modified bitumen roofing has several important advantages for the homeowner, such as durability and low maintenance. Below are the main reasons why many people choose mod bit for their roof systems.
- Leak Resistance: Both hot and cold modified bitumen installation methods create a seamless, tight connection between the bitumen sheets. The multi-level structure enables the roof to endure all weather elements.
- Heat and UV Resistance: Modified bitumen has excellent heat-reflective properties. This quality makes bitumen UV-resistant and energy-efficient, especially if the installation uses a light-colored sheet or includes a reflective top coating.
- Cold Weather Performance: Modified bitumen can remain flexible even in freezing temperatures, so it is less prone to cracking and leaks. Cold resistance is vital for buildings that must withstand long winters.
- Tear Resistance: The reinforcing layers of the bitumen sheets make for a tear-resistant roof. Tear resistance is a must for roofs exposed to heavy foot traffic.
- Color Variety: Many people think of a drab gray surface when they hear “bitumen.” However, nowadays mod bit sheets are available in a variety of attractive colors, including white, black, and tan.
- Ease of Installation and Repair: Modified bitumen comes in ready-to-roll, three-foot-wide sheets that are very quick and easy to install. If the roof surface becomes damaged at any point, a roofing contractor can easily patch it.
- Recyclability: It is possible to recycle bitumen, which makes it an environmentally friendly roofing choice.
Disadvantages Of Modified Bitumen Roofing
With all the advantages of modified bitumen, it does have some drawbacks.
- Lifespan: Although a modified bitumen roof can last over 20 years under favorable conditions, some roofing options offer a longer lifespan.
- Risky Installation: Many mod bit projects involve the torch-down hot application method, which can create a fire hazard and danger to the contractors unless they adhere to a strict safety protocol.
- Tendency to Pond: Like every low-slope roofing system, a mod bit roof may retain water from rains or melting snow. Standing water can lead to serious damage and shorten the roof’s lifespan.
How Is A Modified Bitumen Roof Repaired?
Inevitably, a mod bit roofing system will suffer wear and tear with long-term exposure to the elements. Over time, the roof may show leaks, structural damage, and poor insulation properties.
Often, roof issues will start slowly and worsen over time. To prevent such problems, we recommend an annual roof inspection and maintenance schedule. Regular upkeep will extend your roof’s lifespan and save you money down the road.
During a check-up, sometimes you’ll discover any of the following issues:
- Surface erosion: spots or areas of worn asphalt and possible exposure of underlying layers.
- Delamination: separation or slipping of individual roof layers.
- Tears, punctures, or cracks.
- Water pooling that warps the roof structure.
- Collection of dirt and debris.
In many cases, it is possible to restore a mod bit roof. Repair often involves the following steps:
- Thorough cleaning, pressure-washing, and using a biodegradable degreaser if necessary.
- Carefully sealing all seams and flashings to reduce leaks.
- Treating cracks with roof cement, sealant, or patches.
- Covering the roof with a top coating to create a seamless membrane.
At some point, however, repairs are no longer cost-effective. An honest contractor will tell you openly if they believe your roof has reached the end of its lifespan.
Popular Modified Bitumen Roofing Manufacturers
Some leading modified bitumen roofing manufacturers include:
- GAF: a tried-and-true roofing and waterproofing company operating since 1886.
- Bitec Inc.: a manufacturer of high-quality modified bitumen APP and SBS products.
- Johns Manville: a manufacturer specializing in premium roofing systems, membranes, and insulation materials.
- Polyglass: a market leader producing patented modified bitumen roofing systems.
At Maxx Roof LLC, we work with leading suppliers and are committed to giving our clients high-quality, durable materials for long-lasting roofs.
Work With An Experienced Modified Bitumen Roofing Contractor
After reading all that are you thinking about installing a modified bitumen roof? Need to repair or replace your current roof? Look no further than Maxx Roof LLC, your top-tier residential and commercial roofing experts.
At Maxx Roof LLC, we are loyal to our flagship values: stellar roofing work, quality in all details, and outstanding customer service. Add affordable prices and solid warranties to the list of reasons people love to work with us.
For a free contactless roof inspection and project estimate, call (720) 743-4492 now or fill out our contact form.