Single-ply membranes are a valuable roofing system alternative for commercial and industrial structures. The system is proven to be satisfactory for commercial flat roof applications and is fast becoming a replacement for older multi-layer roofing material systems. In the past and to this day, businesses have incorporated multi-layering roof design systems, but single-ply membranes appear to be just as competitive for flat roof designs.

Why Single-Ply?

There are reasons why single-ply membranes for roofs are being utilized in commercial structures more readily today. They are comparatively less expensive, are fairly easy to install and are a flexible material, but attention should be directed to the actual building and its specific structural requirements before considering the system. Materials and the installation process should be examined before delving into a single-ply application. Other systems should be considered that are compatible with the type of building and its current condition. Understanding the essentials of a single-ply system design is of importance as it will help commercial building owners determine whether the system is the right choice for their roof structure.

Basics of Single-Ply Membranes

A single-ply system is configured with a number of different flexible, durable and ultraviolet resistant materials that are prepared in a one layer configuration. The actual membrane consistency is mainly synthetic polymer which can be reinforced with polyester and glass fiber. The membranes are sealed at the joints to provide waterproofing and when they are joined with insulation, a strong support system is established and the membrane becomes a complete system. The basic make up of a single-ply system should be thoroughly assessed and the benefits and hindrances understood before choosing the system for any roofing project.

Single-Ply Membrane Types

1. Thermosets

The membranes in Thermosets are synthetic and consist of rubber polymers that include Neoprene, EPDM and CSPE. These polymers protect against the ultraviolet rays of the sun as well as any damaging chemicals that can be found in and around a roof area. Their manufactured size is ideally made for larger roofs which limits the number of seams on the membranes and also helps eliminate problems with the wearing and tearing of seams.

Tape or a contact cement is used to adhere the materials and create the lap or overlap. EPDM black membranes contain carbon black that serves as further UV protection for membranes, while membranes that are white often have added titanium dioxide which also helps with reflection and damage from UV rays.

2. Thermoplastics

Thermoplastic single-ply membranes are made from PVC and TPO plastic materials, and their seams are brought together through hot-air welding that seals the materials together and forms a lap or overlap with the membrane materials. There is usually another layer of reinforcement included in the manufacturing process that contains fiberglass or polyester that adds stability and strength to the membrane. These types of membranes are basically light colored which allows for reflectivity and ultraviolet protection along with considerable savings in energy usage.

Whether a thermoset or thermoplastic single-ply membrane is used, both contain a flexibility feature as well as protection from the ultraviolet rays of the sun. Though these membranes are not difficult to install, they do have the drawback of incapability with other single roofing systems.

How is Single-Ply Roof Material Installed?

Installation of a single-ply roofing system will be determined by the structure itself and any of the particulars and peculiarities that are part of the structure. There are preferred installation methods that include:

1. Ballasted roofing

A ballasted roof (one in which a membrane has no adherence to roof decking) would be better able to receive a single-ply system because of its structural nature and ability to take on additional weight. Its components usually consist of gravel, stones or pavers that are loosely in place and are not connected or fastened to the roof membrane or deck. Gravel and other stones are situated to protect underlying roofing materials and to secure or weigh them down, especially in a single-ply application.

This type of roof would be better able to take on the additional weight of a single-ply membrane; however if there were any major slope to the roof, the membrane would likely not function well. The finish is usually black or white and is either installed through fastening, gluing or precise placement over roofing insulation.

2. Steel or Wood Roofing

Steel or wood roofs are better able to handle single-ply membrane roofing that is mechanically fastened. Mechanical fastening involves using the right number of fasteners to secure a single-ply application. If an insufficient amount of fasteners are used, the application could be blown away through strong or hurricane force winds.
This type of fastening is adaptable with all types of slope roofs but if the structure is in a high wind zone, wind lift can be avoided with both a mechanical attachment on the perimeter of the structure along with a manufacture-recommended adhesive.

3. Fully Adhered Roofing

With fully adhered roofing, a single ply application is an additional option to consider. The membrane would be attached using a manufacture-recommenced adhesive, which could be solvent, water or asphalt based. With this type of installation, a smooth finish would result and it would allow for the use of colored membranes for a more pleasing surface presentation.

Single-Ply Costs

Single-ply roofing costs are determined by square footage, and the current price of materials in the marketplace. The average is anywhere from three to five dollars per square foot, or less. When EPDM ballasted roofing is used, the material and installation costs are generally lower per square foot than other single-ply materials. Also, material costs usually don’t include the expense of insulation.

Pros and Cons of Single-Ply Membranes

The Pros:

  • Large number of grades of protection available
  • Installation ease
  • Affordable
  • Lightweight material
  • Limited maintenance
  • Recyclable
  • Endures climate and weather condition fluctuations
  • Superior reflective abilities
  • Energy efficient
  • Protective against acidic pollutants (acid rain)
  • No issues with the proximity of other chemical substances

The Cons

  • Shorter duration of life/use
  • Thinner surface area
  • Easily punctured surface area
  • Water retention susceptibility
  • Seam issues

Single-ply membranes have many advantages and whether you choose single-ply or another roofing system, it is important to take building type, maintenance and proper installation into consideration. Utilizing a trained roofing contractor with single-ply membrane experience is also critical. If you are considering a single-ply system, complete the online contact form and a roofing professional will get back to you with answers to any of your questions or concerns.