If you are considering building a new roof for your house or commercial property, a built-up roof, otherwise known as BUR, might be a good option for you.
However, if you don’t know what that is, no worries, because we’re about to do an in-depth review of what exactly built-up roofing is, and what its pros and cons are. By the end of this article, you should know whether or not built-up roofs are the right choice for you.
What Is Built-Up Roofing?
Built-up roofing, simply known as BUR, is a special type of roofing system that is commonly used for industrial buildings and commercial properties.
For many years now, this type of roofing system has been very popular for both low-sloped roofs and flat roofs, although it is generally not used for regular sloped roofs, such as on the typical American house.
This roofing consists of various layers of either coal tar or asphalt bitumen, alternated with a variety of reinforcing fabrics, which may include organic materials such as paper or felt, as well as fiberglass. These layers are built-up on top of each other, hence the name, and stuck together using bitumen, which creates a durable and strong roofing membrane.
There are a variety of layers that this type of roofing usually involves, starting with a vapor retarder that is designed to prevent moisture from seeping into the building, and this is applied directly to the deck. The second layer generally involves insulation, which is applied above, which helps to improve energy efficiency.
You then have the membrane layers, which consist of various layers of reinforcing fabrics in bitumen, which are alternately laid on top and mopped, which means that they are applied with hot asphalt, to form a monolithic and continuous membrane. Exactly how many layers are used depends on the application in question.
The final layer involves surfacing, which means that there is a mineral cap sheet or a layer of gravel put on top, which helps to ward off UV radiation, physical damage, and damage caused by weather.
This is a fairly labor-intensive process because there are many layers that need to be installed, but this type of roofing is also great for warding off water, it’s durable, and it’s very resistant overall, meaning it can last for several decades.
8 Pros of Built-Up Roofing
Let’s take a quick look at the advantages of built-up roofing.
Durability and Longevity
Overall, this is a very durable type of roof, and if properly installed, those multiple layers can last for up to 30 years or even longer. It’s one of the most durable roofing systems around. This type of roof also tends to be quite resistant to mechanical equipment and foot traffic.
Thanks to the vapor barrier, the waterproofing membranes, and the multiple layers of bitumen and reinforcing fabrics, this type of roofing is very effective at keeping water away from the interior. This is very important for low-sloped and flat roofs.
Due to the added layer on the exterior, the mineral cap, or the gravel, it’s also very UV-resistant. It prevents the roof itself from suffering from UV damage.
The next benefit of a built-up roof is that it is also very resistant to the weather. All of those layers come together to keep water, wind, and other elements at bay. It’s definitely one of the better roofs to use if you live in an area that has inclement weather.
Thanks to the fact that this type of roofing can be installed with additional insulation layers, it can also help to improve the overall efficiency and thermal performance of a building. At the end of the day, this can help reduce both heating and cooling costs.
Yet another big benefit of a built-up roof is that it is very resistant to fire. When many layers of bitumen are used, along with mineral surfacing and gravel, this type of roof features excellent fire resistance.
Although some problems can be difficult to solve, in general, repairing a built-up roof is as easy as just adding new layers of reinforcing fabrics and bitumen.
Built-up roofs can be quite expensive to install, but thanks to their long lifespan, minimal maintenance, and thermal benefits, they tend to be very cost-effective in the long run.
6 Cons of Built-Up Roofing
Now that we know what makes a built-up roof beneficial, let’s figure out what its drawbacks are.
This type of roof is very heavy due to all of those layers, and this may spell disaster for older buildings. Some buildings may require structural reinforcement to support the weight of a built-up roof.
Another big drawback of built-up roofing is that it requires skilled roofing professionals to install, and it is very labor intensive. This is a time-consuming process, and it can also be quite expensive.
Although this type of roofing is very resistant to moisture, a problem it has is that water often tends to build up or pond on top of these flat roofs, which can lead to pretty serious damage.
Fumes and Odors
This type of roof has to be installed using hot asphalt, which can release some very strong fumes and odors. Furthermore, it can also be dangerous to the people installing it.
High Initial Cost
Yet another drawback of this roofing system is that the initial cost is quite high. If you are on a tight budget, the upfront cost might simply be too high for you.
The fact that using bitumen and hot asphalt is not very eco-friendly is something that you must consider. This just is not a very sustainable or eco-friendly roofing method, and for some, this is really quite important.
Should You Use Built-Up Roofing?
What it comes down to is that if you have a flat roof or a low-sloped roof, you need a method that has good fire and weather resistance, handles foot traffic just fine, and is relatively easy to repair, then a built-up roof is always a good option to consider. Just keep in mind that the upfront cost is fairly high, and installing this type of roof also isn’t very eco-friendly.
Now that you know exactly what a built-up roof is, you can make an informed decision as to whether or not this is the right type of roof for you.
If you do not think this is the best option, then you might also want to read our article about the best types of roofing materials for flat roofs.