Single Ply Roofing Basics

Pros and Cons of Single Ply Roofing

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Single Ply roofing membranes provide a variety of materials to choose from. Their main characteristic is that they are designed to be installed in one layer. They also exhibit great flexibility and their resistant to UV radiation is superior when compared to other products. It is usually black or white finish, and glued, fastened or install directly over roof insulation material.

Types of Membranes

Single-ply membranes can be generally categorized into two groups: Thermosets and Thermoplastics.

Thermoset membranes are compounded from synthetic rubber polymers, and the most commonly used polymers are EPDM, CSPE and Neoprene.

Thermosets membranes are ideal for large roof areas, due to the fact that their manufacturing size is ideal to reduce or minimize seams. The majority of EPDM thermosest black membranes have carbon black as an additional component, which increases the UV protection; and in the case of white membranes, the manufacturer adds titanium dioxide, increasing the reflection property against UV rays.

Seams on thermoplastic single-ply membranes can be hot-air welded together to form cohesive laps. When thermoplastic membranes cool, they return to their original material type. Two of the most commonly used thermoplastic single-ply membranes are PVC and TPO, both of them plastic-based materials. Thermoplastic membranes are usually manufactured to include a reinforcement layer, normally polyester or fiber glass that provides additional strength and stability.

Both types of membrane are highly flexible and resistant to ultraviolet radiation. These types of membranes are relatively easy to install, but normally are also incompatible and cannot be used in combination with other single roofing systems.

Single Ply Roofing Installation Methods

The type of installation for the single ply roofing will depend on each particular situation and building.

Ballasted roof might be the best and preferred installation method when the structural roof is capable to withstand the additional loads. Nonetheless, in the case where the roof has a slope greater than 1" in 6", then this method might not function properly.

A steel or wood roof might be ideal for mechanically fastened singly ply membrane roofing. Mechanically fastened single ply roofing might be used on all types of slopes without limitations and they are one the preferred option in hurricane-prone areas.

A fully adhere single ply roofing might be another option for you to consider. If you choose these solution, the membrane needs to be attached using an adhesive recommended by the manufacturer and it might be asphalt, solvent-based or water-based adhesive. Using this installation method, the finished surface will be smooth and can be used along with colored membranes to provide pleasant aesthetic surfaces.

Single Ply Roofing Cost

The cost associated with the material and installation can vary widely depending on roof conditions, attachment used and type of membrane being installed. Single ply roofing is priced per square foot, and an average price for materials and installation of a 60 mil roof may range from $3 to $5 per square foot.

As a starting point and if you working on a proposal you can use the following numbers for your cost estimate:

  •  EPDM Rubber cost of material is about $1.50 per sq foot (excluding insulation), making the cheapest single ply roofing membrane.
  • TPO roofing is about $1.70 per sq foot (excluding insulation).
  • PVC roofing is about $1.90 per sq. foot (excluding insulation).

Pros and Cons of Single Ply Roofing

Pros

  • Excellent against acid rain conditions
  • Excellent performance under dramatic weather changes
  • Will not suffer major problems under the presence of chemical materials
  • Wide variety of grades available to choose from(grades are the type of protection desire from the product)
  • Lightweight product
  • Excellent reflective properties
  • Easy to install
  • Economic feasible

Cons

  • Thinner surface that can be easily punctuate
  • Relatively short lifespan
  • Seam problems might arise
  • Can be susceptible to water retention problems