Single-ply means just one layer of membrane as a waterproofing and weather surface.
Single-ply membranes are generally categorized as either thermoplastic or thermoset. Thermoplastic materials can be repeatedly softened when heated and hardened when cooled. Thermoset materials solidify, or “set,” irreversibly after heating. Single ply membranes commonly are referred to by their chemical acronyms, such as ethylene propylene diene terpolymer (EPDM).
Single-ply membranes may contain reinforcement layers. Common reinforcements for single ply membranes include polyester fabrics or scrims, glass fiber, or a felt or fleece backing. A finished sheet’s thickness typically is referred to as mil thickness; 1 mil equals 0.001 inch. Common mil thicknesses for these sheet membranes range from 30 mils to 60 mils.
Single-ply membranes can be installed fully adhered, mechanically attached or held down with ballast. Most single-ply roof systems do not receive surfacing.
In many instances, a combination of attachment methods are used to secure a roof system. For instance, an insulation may be mechanically attached to the substrate with the roof membrane fully adhered to the insulation.
EPDM (Ethylene Propylene Diene Monomer), PVC (Polyvinyl Chloride), and TPO (Thermoplastic Olefin) are the major types of single-ply membranes.
Today, single ply membranes are the most popular flat roof materials used in both commercial and residential construction.
Single ply roofing is not all equal in quality and longevity. EPDM, TPO and PVC all have very different formulations, durability specs and cost.
Membranes range in width from 6-18 feet. The ones most commonly used are around 10 feet.
The average thickness ranges from 45-90 mil. It is typically recommended to install a membrane that is at least 50 mil thick.
This type of system provides long-term durability and the security of heat-welded TPO’s advantages include:
> TPO traditionally has a white ‘reflective surface’ which reduces cooling costs.
> TPO roofing systems are the most environmentally friendly of the single-ply systems.
> They produce no dioxins or chlorine. Membranes come in varying thicknesses to meet your specific requirements and are available in varying roll widths.
These systems are among the easiest single-ply roofing membranes to install and heat-weld together.
> These systems are able to resist various chemical effluents.
> They provide superior resistance to punctures and tears.
> PVC systems are especially suited for roofs that are exposed to concentrations of grease, oils and many kinds of fuels.
> In areas where acid rain or other forms of acidic outflow is a problem, PVC roofs are the preferred solution.
This system is a black single-ply membrane, often referred to as “rubber roofing.”
> EPDM systems require minimal maintenance and are resistant to UV radiation and ozone.
> EPDM technology has proven effective for more than 30 years.
> It withstands temperature extremes and expands and contracts with the building.
A flat roof costs less than a pitched/sloped one.
EPDM cost of material is about $1.50 per sq foot (excluding insulation), making the cheapest single ply membrane.
TPO is about $1.70 per sq foot (excluding insulation).
PVC is about $1.90 per sq. foot (excluding insulation).
Installation prices quoted below are for very simple roofs, over 1,000 sq. feet. Your total cost will vary depending on many variables, such as roof size and complexity, geographic region, etc. Any additional insulation and details will increase the cost.
PVC roofing cost 6.50 – 7.50 + per sq foot installed.
EPDM rubber cost $5.50 – 6.50 + per sq foot installed.
TPO roofing cost $6.0 – 7.0 per sq foot installed.