What Is a Low-Slope Roofing System?

Low slope roofing systems refer to a roof that is nearly flat or slightly pitched. Of course, no roof should be dead flat, ever. If so, the water will not be able to flow in any particular direction. A watertight, monolithic membrane must be formed that remains watertight all the way to the edge or drains.

While a steep slope roof relies on gravity to shed water, low slope roofs do not. In the modern day, low-slope roofs rely on the aforementioned membrane, so that pools of standing water are more easily resisted. Heat welding and other adhesives are used, as the membranes are applied as continuous sheets.

Those who are looking to spend a bit more may decide to utilize sealed metal low-slope roofs that rely on copper or tin. These interlocking systems of metal panels are soldered together. Tar and gravel roofs were used in the past, but the performance and cost concerns associated with them have caused homeowners to pivot in a different direction.

Freeze/thaw cycles, UV radiation, and wind performance can all be problematic for a flat/low slope roof. That’s why they must be able to withstand expansion and contraction. They must remain 100 percent watertight as well, which requires well-engineered attachment, weathering, and seaming to prevent any performance concerns.

The 3 Types of Low Slope Roofing Systems

Built-Up Roof

In order to build up a strong watertight membrane, multiple layers of roofing felt are mopped into their appropriate place. Coal tar pitch or hot asphalt is used. To surface the membrane, coating or gravel is then embedded within a pour coat that contains more hot bitumen. This style of roof is associated with lasting performance, but it is not a very flexible membrane. Crude oil prices can make this process cost prohibitive, and there are also various environmental concerns.

Modified Bitumen

With modified bitumen roofs, the asphalt is chemically modified for greater flexibility. A heavy polyester or fiberglass mat is used as the base, for added strength. There are a wide range of application methods and a proven track record of performance, as well as high tensile strength.

Life cycle costs are competitive, long-term warranties are available, and the waterproofing characteristics are superior. “Cool Roofing” options are included among the top surfacing choices. Insulation can be provided for a better-performing building component. Modified bitumen is also available as part of hail, fire, and wind-rated roofing systems.

Single Ply

With this style of roofing, factory-controlled conditions are utilized to construct entire membranes that are installed as single-ply. Thermoplastic membrane roofs are single-ply membranes that are welded by heat. Typically, these roofs are white, which allows them to reflect and receive a high Energy Star rating. Durability is no problem because the seams are welded, and every aspect of their care and installation is environmentally friendly.

In fact, these thermoplastics are the fastest-growing form of low-slope roofing. This style of low-slope roof is also known for its wide range of application methods, a proven track record of performance, high tensile strength, and superior waterproofing characteristics. These roofs are part of a “Class A” fire-rated roofing system, and insulation is used to provide a building component that offers even better performance. Cool Roofing” options are also among the best surfacing choices.