When in the market to build your new roof, you will need to know what materials will be best to do this with. In this article we will go over the typically used materials for a Low-Slope Roof. Low slope or flat roof, where the slope rises less than four inches in a run of 12 inches , these will require a special system to prevent you from having any leaks. Whatever system you have protecting a giant industrial building or your home, you want to choose the best system for your structure. Most low-slope roofs are now built or re-covered with one of four main material types, TPO, PVC, EPDM or Modified Bitumen, while Built-Up declines in popularity. We will discuss these different types and what the use for each will be, let’s get started!
Built-Up Roofing
Built-up roofing, also called BUR, this is one of the most popular roofing material used on low-slope roofs. BUR is built of alternating layers of reinforcing fabric and bitumen (asphalt) and is finished with a top layer of aggregate, for example stone or gravel. You may be asking what the difference between BUR and modified bitumen is, Modified bitumen is a roofing membrane consisting of asphalt and plastic or rubber polymers, and is therefore widely considered an evolution of asphalt built-up roofing (BUR). Modified bitumen displays the built-in redundancy of asphalt built up, as well as the UV resistance and flexibility of a modified membrane. Another factor that could come into play is the cost of this material, the average roofing installation price for a tar & gravel (built up) roof costs anywhere between $3,750 to $6,750 depending on the slope, pitch, and size of your roof. You can expect to pay $2.50 to $4.00 per sq. foot or $250 to $400 per square installed on a standard sized single story home.
Modified Bitumen
One of the other options to use which we previously discussed is the Modified Bitumen, this is also known as Atactic Polypropylene (APP) or also called Mod-bit. This is an asphalt product, modified bitumen does cost a lot less than when you use the plastic and rubber membranes and it is known for holding up very well just as long as the roof never has to sustain pooling water. The options here include torch-down, this is where the crew melts the back with a torch as they are rolling it out, or they peel and stick the self adhering membrane. This is known as the most up-front economical choice. This option will require replacement more often than some of the other options in materials. Another bonus to this material is that it comes in many different color options for you to pick from!
EPDM
A modified rubber material, Ethylene Propylene Diene Terpolymer (EPDM) brings many benefits to any flat roof system. This is incredibly flexible, EPDM can last through decades of hot/cold cycles and differential settling of the building without difficulty if it is fully adhered. Chemically inert, EPDM can withstand almost any chemical. Furthermore, this is the same material used to line leach pits and retention ponds. The most commonly used color is black, EPDM comes in white, as well. Of all the single-ply membranes, EPDM can handle hail the best. Also, as a rubber product, EPDM easily resists punctures under ordinary conditions; however, gravel embedded in boot soles can cut the membrane, so it may not work well where there will be heavy foot traffic. If you are in the market for a tough material this may be the one you need to dig deeper into and see if this is the material you should go with.
TPO
TPO is a new material to most roofing projects. TPO stands for Thermoplastic Polyolefin, this means it is a single-ply membrane with many different beneficial factors. As this is a plastic material, the seams can be heat welded so you have lots of durability. If you live in an area that is known for its hot weather and you normally have a lot of sun that hits your roof, you would need to use the white TPO because it reflects the light and will keep the interior of your home or building cooler than if you used a black color for the job. This material will hold up in weather that may come around. If you have a tough hide this material withstands punctures and will stand up against hail.
PVC
Before TPO came into the roofing world, we normally used PVC , which stands for Polyvinyl Chloride, this was the king of the single ply roofing. This material has many similarities to TPO. Architects and others in the building world found this was a good alternative to tar and gravel systems known as BUR. This is a bendable and capable of of heat welding, also a plus this cool roof qualified, the advantage over TPO comes from how it can withstand many chemicals. PVC is a wonderful membrane roof covering for any building that has a vent system installed.