There are many different types of roofing systems available today which makes it more confusing when choosing one for a commercial building. Although affordability and durability are the most common factors that are considered when choosing a roofing type the added advantages that a particular roofing material might offer also come into play while making the decision. Below is a quick look at the built-up roofing system and single-ply membrane roofing system which are two of the most common options recommended by commercial roofing services.
Built-up roofing has been one of the most preferred roofing systems in the US for more than 100 years now. Also known as “tar and gravel” roofs, built-up roofing is installed by alternating asphalt or tar layers along with supporting fabrics that are directly placed onto the roof. The number of asphalt or tar layers depends upon the area of the roof to be covered which is then topped with a layer of stone or gravel.
Commercial roofing services install built-up roofing by applying the first layer onto the roof substrate directly. Sometimes, a base sheet is fixed to the roof as well in order to get a flat and safer workspace. Following that, alternating layers of tar are laid onto the layer along with the reinforced fabric. Then the final layer of rock or stone is applied to protect the layers underneath from extreme weather and to improve its durability. The final layer of stone or gravel also makes the roof more aesthetically appealing.
The cost of installation of built-up roofing usually ranges from $5 to $10 per square foot area but it can vary depending upon the roofing materials as well as the labor charges. The property owners can choose the number of asphalt or tar layers as per their budget and roofing needs.
Single-ply membrane roofing involves using rubber or other synthetic material sheets that are chemically attached or ballasted to create a roof insulation layer. Generally, single-ply membrane roofing is categorized into two main types: Thermoplastic Polyolefin or TPO and Ethylene Propylene Diene Terpolymer or EPDM. Their main difference lies in their composition and chemical structure which has a direct influence on how they are installed and how energy-efficient the roof will be. Additionally, TPO roofs are normally white in color, making them highly reflective, while EPDM roofs feature a natural dark color that makes them more heat retentive.
Regardless, both the types of single-ply membrane roofing are installed in a similar way. First, the roof substrate is prepared for the work either by cleaning the roof or removing it entirely. Then insulation layers are installed onto the prepared surface and covered using a cover board. The insulation layer can be Polyisocyanurate, Extruded Polystyrene, or Expanded Polystyrene depending upon the choice of the property owner. Then the final membrane is attached to the cover board by either ballasting, by mechanically fastening it, or by using an adhesive.
The installation costs of the single-ply membrane roofing system range from $4 to $8 per square foot area. However, this can vary depending upon whether you choose TPO or EPDM roofing material as well as the labor costs. Note that TPO roofing employs a hot-air gun to melt the membrane seams and stick them while EPDM uses a seam tape for the purpose.
Pros and Cons of Built-Up Roofing and Single-Ply Roofing System
Built-up roofing can last for more than 40 years if properly installed and maintained well. Since they have a continuous solid surface there are no joints or seams on the roof which helps reduce the chances of leakages and other such issues. The final stone or gravel layer of the roofing system also provides UV protection to it, while making sure that it requires very low maintenance and upkeep. However, the main disadvantage of a built-up roofing system is that it can take a lot of time to install the roof. Moreover, it can also add a bit more weight to the commercial building structure.
Single-ply membrane roofing can last for more than 30 years if installed by a professional commercial roofing service provider. They have a proven track record for their energy efficiency and have been used in commercial buildings for more than 60 years. Many laboratory and field tests have also been conducted on the roofing materials, which have found them effective for commercial use. Besides, both TPO and EPDM roofing systems are Class A fire-rated which assures the user of their durability and long life.
The main drawback of single-ply membrane roofing is that exposure to UV rays can degrade the adhesive material quickly. They do not have a hard top layer to protect the roofing membrane from harsh weather or other damages either, making proper maintenance of the roofing mandatory to maintain its longevity. Sometimes the presence of seams can also make them vulnerable to leakage problems as well.
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