What Is Modified Bitumen Roof?

Modified Bitumen Roofing system is the common low-slope roofing system. It is not like asphalt roll roofing, TPO, or EPDM.

Modified Bitumen doesn’t consist of hot asphalt with plastic and rubber additives. Between sheets of polyester or fiberglass, they are layered.

In the mid-1960s in Europe, modified bitumen first appeared in commercial roofing. The conventional roofing system was built-up roofing. It is made of an asphalt layer with a top layer of gravel.

The BUR is very useful, but it has some downsides too like it is heavy, it is expensive to install, it doesn’t work well in extreme temperatures, and it is difficult to repair.

It was successful in resolving the problems with BUR, it is easy to install, and it works properly even in extreme temperatures like cold weather.

By 1975, modified bitumen was being used in the United States. Now it is one of the most reliable roofing systems.

Today in this post, you learn about what is modified bitumen roof is. How to install modified bitumen roofing?

Also Read: Top 38 Patio Roof Options

What Is Modified Bitumen Roof?

Modified Bitumen Roofing system is the common low-slope roofing system. It is not like asphalt roll roofing, TPO, or EPDM.

Modified Bitumen doesn’t consist of hot asphalt with plastic and rubber additives. Between sheets of polyester or fiberglass, they are layered.

This type of roofing is typically used in Seattle because it gives resistance to tearing. The fiberglass and polyester reinforcement layers help the material to become tear-resistant.

There is everything in the article you want to know about Modified Bitumen Roofing. You come to know about.

What is Modified Bitumen roofing, its history, how to install it, its type, its advantages, and disadvantages? By knowing all of this, you can know what kind of roofing you want to do in your house.

It also gives the waterproof characteristic to the roofing. It also handles foot trafficking well. So it has good advantages over another roofing system which you will read below in the article.

You can take a look at the advantages and disadvantages of the system and compare it to others. Though there are disadvantages to this system, it can be solved by maintenance and precautions.

And the advantages weigh down the disadvantages. It has many advantages, which many house owners prefer. Hope so you get some good out of this article.

The framework of the Modified Bitumen Roofing system is a combination of five-layer roofing components.

The Five Layers Are: insulation Modified Base Sheets or Piles Modified Between Membranes, Adhesive Surfacing

1. Insulation: This layer is used to give R-value or thermal insulation resistance for the temperature stability of the roofing system.

2. Modified Base Sheets or Piles: this layer gives the system the flat surface it has.

3. Modified between membranes: It is a sheet membrane that contains co-polymer reinforced with polyester or fiberglass. This membrane is fabricated in factories.

4. Adhesive: This layer is added for waterproofing. It can be applied on the roof’s surface, either cold or hot.

5. Surfacing: This layer provides protection from UV rays and is used as weather resistance.

Also Read: Top 40 Patio Roof Ideas

What Are the Benefits of Modified Bitumen Roofing?

There are various benefits of modified Bitumen roofing that are as follows:

1. Energy Efficient: Most of the modified roofing systems provide resistance to UV rays. And because of this, the houses are able to maintain the inner temperature well. And It does not affect the HVAC system much. So it saves on energy bills.
2. Tear-resistance: Modified bitumen gives fantastic durability and strength to the roof. It provides resistance from the tearing of debris, weathering, and consistent foot traffic.
3. Waterproof: It also protects the house from moisture. If it is installed properly, it gives waterproofing protection to the roof. And because of its multiple layers, it is more efficient in waterproofing.
4. Flexible: It contracts and expands easily with changing weather conditions. It is flexible in its working method and doesn’t lose its efficiency.
5. Easy to Install, Repair and Maintain: It is very easy to install, so it helps the staff to install it. It is easy to repair if there are any leaks or cracks. It can be maintained well.

Modified Bitumen Membrane Roofing Types:

modified bituminous membrane roofing is categorized into two types-APP, and SBS

1. App Roofing System Membranes:

Atactic polypropylene (APP) is commonly known as plastic asphalt. APP membrane contains a plasticized polymer that shows elasticity properties when going through high temperatures.

It protects the house from UV rays and also gives the structure of the roof a cool look. It is preferred by people who want to protect their houses from extreme conditions.

Also Read: Top 12 Exterior Black Roof House Color Schemes

2. Sbs Roofing System Membrane:

Styrene-butadiene-styrene (SBS) is referred to as an elastic rubberized asphalt membrane, it contains asphalt with polymerized rubber which gives it flexibility and elasticity property.

If your roof expands and contracts in extreme climate conditions, it is one of the best types to choose from. SBS roofing installation also protects the house from high winds.

Application Methods for Modified Bitumen Roof

There are different types of Modified Bitumen roofing systems to install. Below we are going to read about the two different types of installation of Modified Bitumen roofing.

Two types of Bitumen roofing installation are: The torch-Down installation method and a peel and stick installation method.

Tools Used in the Installation of Modified Bitumen Roofing

• Measuring tape
• Hammer
• Chalkline
• Large propane torch
• Utility knife with a hook blade
• Spark igniter

Materials used in the installation of Modified Bitumen Roofing

• Roof insulation
• Heavy roofing felt
• Modified-bitumen roofing
• Drip-edge and other flashings
• Spray primer
• Cap’s nails
• Roofing nails
• Roofing cement

So here is a step-by-step guide to building up a modified bitumen roof.

How to Install Modified Bitumen Roofing?

The process of the installation of the Torch Down Bitumen Roofing is as follows:

• This process is dangerous for those who want to do it alone because it involves working with petroleum products and felting. Because of the work required to be done using fire, it must be done by professional roofing. So here is a step-by-step guide to installing torch-down modified bitumen roofing:
• First, you have to check the roof properly and eliminate all the debris in the area for better results.
• Overtop your decking, insulation, or old roof and install heavy roofing. Secure the felt properly by using cap nails to the rows along the top and bottom and the sheets. And repeat that for the middle rows.
• Drip edge flashing should be installed in this step, and then the primer should be applied so the roofing will adhere to it.
• In this step, you must roll out the roofing sheet, leaving an overhang for a few inches on all sides of the roof. Then again, allowing a few inches of overhang on the roof cut the roofing.
• Adjust the roofing so it can overhang the flashing by a half-inch, and check the roofing; it should be perfectly flat. Otherwise, the installation won’t work properly. Then carefully roll back the roofing back up tightly halfway.
• For this step, you must wear heavy gloves and long sleeves for protection from a propane torch.
• Turn on the propane torch and spread the tip of the flame along the crease between the roofing roll and the roofing felt. Gently roll the roofing forward with your foot when you see bubbles forming during the process of installation.
• The next sheet should be aligned in a way so that it can cover the edge of the sheet of modified bitumen roofing by a few inches. And after that, repeat the process again.
• Press the seam between the two sheets using your foot and gloved hand. Then ensure that it is tightly sealed. A bit of melted bitumen should be oozed out along the joint.
• Repeat this process for the remaining portion of your flat foot.

How to Install a Peel-And-Stick Modified Bitumen Roofing?

It is a built-up, modified bitumen roof that is a type for do-it-yourself. As it does not involve working with fire and fumes, you can do it by yourself. So here are the steps to install peel-and-stick modified bitumen roofing.

First, the five-step is exactly similar to the torch-down modified bitumen roofing installation, which is written above. After following those steps, then you can start working on the steps which are written below.

First, you have to remove the adhesive film and carefully roll the roofing back into the original place. Before adhering the material to the flat roof, ensure it is smooth out.

Leaving an overlap of at least six inches, repeat this process for the entire area of the rooftop.

Roll over the entire area of your roof by using a weighted roller. Pay special attention to the overlap. Otherwise, it will not be done properly.

Seal the edges of the Modified Bitumen Roofing with the help of roofing cement. Then roll all the sheets together to seal them together.

Modified Bitumen Roof Problems

The problems with the Modified Bitumen roofing system are that it has low life expectancy than other roofing systems. It can work well for 10-20 years approximately. Then you have to change the system or upgrade it.

It is one of the main reasons people choose another roofing system, as they want their roof to last for a long time.

It is not easy to install if to choose torch-down modified bitumen roofing. As it involves working with fire and heat.

In the installation process, a blow torch is used to extreme heat to install sheets on top of the roof. If you come in contact with harmful fumes, it can be dangerous.

It also has a problem with the drainage system, as it is a flat roof, it doesn’t have to the drainage system. The water gets collected on the roof’s surface, and if the water is not removed quickly, it can be absorbed by the roof. It can create mold and mildew on the roof.

It can be coated faster than other types of flat roofs. The modified bitumen roof system gives off a strong unpleasant odor after the installation process is complete.

How Long Does a Modified Bitumen Last?

Modified Bitumen Roof Systems can last for 10-20 years. Which is less time in comparison to another roofing system. The amount of time Modified  Bitumen roofing lasts depends on many things.

Like the materials used, if the system is installed properly or not, if it is checked frequently and if there is any issue repair should be done properly and maintained well.

Built Up Roof Vs Modified Bitumen

Built-up and modified bitumen roof systems are usually designed for low slope or flat roof structures. While both can withstand harsh weather conditions and harmful UV rays, the two are different in terms of design, application, advantages, and life expectancy. Read on to learn more about these roofing systems and evaluate the best option for your commercial building.

Modified Bitumen Roofing Installation

A modified bitumen roofing system can be installed using the torch method, asphalts, or cold adhesives. A standard SBS-modified bitumen roof system is a two-ply system applied in rolls overlapping the edge of the previous roll.

Advantages of a Modified Bitumen Roofing

Here are some advantages that the installation of the Modified Bitumen Roof System provides:

1. Seamless connections: There are three ways to install modified bitumen roofing- self-adhesive, cold adhesive, and heat. These are the reasons why the sheets are seamlessly connected properly. It has efficient adhesive nature, which makes the connection between the sheets of the roof durable.
2. Tear resistance: It is made by a combination of fiberglass and polyester reinforcement. Which made the sheets tear-resistant and durable. It also handles foot traffic well. Because of this, it doesn’t have to be repaired quite frequently.
3. Weather resistance: The modified bitumen roofing system is a composition of five-layer to withstand extreme conditions in all climates. It doesn’t allow much heat to pass through the house’s roof. It is also good for cold weather. And it also works efficiently in other environmental conditions.
4. UV rays and heat resistance: This system is well known for its heat-reflective property. Because of the heat reflection, it protects the house from harmful UV rays, which is not only bad for the house but also for the people living in it. This reduces the house’s energy bill. So it is a money-saving scheme in the long term.
5. Leak resistance: It is a flat roofing system that is leakproof. The materials used in this system help the area to be leak-proof for a long time. Its coherent nature made it easy to do that.
6. Style options: The materials used in this system have several varieties, which help you to customize it according to your taste. The color of granules in the cap sheet can choose according to the color of the shingles used in the roofing of your house. You can choose the outside look it gives because of the different types of materials used in this.
7. Easy to install and repair: It is easy to install. It can be done by yourself. You can easily do the peel-and-stick installation modified bitumen roofing method. There are rolled sheets 3 feet wide and up to 36 feet long, which can be rolled easily on the top of the base sheet of the roof. The repair can be done easily and quickly by using bitumen patches on the cracked surface.
8. Environment friendly: The sheets used in this can be recycled. You can reuse the sheets by dumping them outside. It not only saves you money but it helps in reducing the waste of material, which is good for the environment. It reduces the carbon footprint.

Disadvantages of a Modified Bitumen Roof

Here are some disadvantages of the Modified Bitumen Roof system

1. Lifespan: The average life expectancy of Modified Bitumen Roofing is 10-20 years. It is quite a good time for the roof, but if you compare it with other systems, it is very low time. Other types of flat roof systems sustain for more years than this. So if you want your house to be protected long-term, there are better options for a roofing system than this.
2. Water resistance: The absence of a drainage system on the flat roofing system makes it quite difficult for water to run down the roof. Water gets collected on the surface of the roof, which spreads the moisture in the house. Which can turn into mold or mildew at any time.
   Modified bitumen in comparison to other flat roof types like TP or PVC, wears down faster. It can damage the roof if it doesn’t get repaired immediately.
3. Torch fumes: During the modified Bitumen roofing installation process blow torch is used to extreme heat to install the sheets on the roof. Those fumes can be harmful if it comes in contact with people. It also causes some health issues. And it has a good effect on the environment.
4. Foul odor: It gives a strong odor after the completion of the process of installing the Modified Bitumen System. The effect of the odor depends on the area covered in the installation. It is better to relocate temporarily during the process of installation of the roofing system is going on. It will help you to avoid the foul smell of the roofing system.

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