Is a Single-Ply Membrane Roof System Right For You?
It’s time for a new roof but you might wonder, is a single-ply membrane roof system right for you? Kauffman Roofing in Jamesport can walk you through all the details, help you decide if it’s the best decision for your building, as well as provide a professional installation.
What are single-ply membrane roofs?
These are factory-manufactured sheet membranes either called thermoplastic or thermoset.
Thermoplastic membranes are softened when heated and hardened when cooled. The chemical nature allows it to be seamed by heat welding with hot air or solvent welding to form cohesive laps. When thermoplastic membranes are cooled, they return to the original hard material type.
They have a reinforcement layer produced by extruding, calendering, or spread coating and may have reinforcement layers like glass fiber, polyester fabrics or scrims or a felt or fleece backing. This gives increased strength and stability. These single-ply membrane roof systems are characteristically light in color, providing excellent reflectivity resulting in energy savings.
These roofs are installed fully adhered, mechanically attached, or held down with ballast. A combination of attachment methods is used to secure a roof system. The polyvinyl chloride (PVC) and thermoplastic olefin (TPO) membranes are two of the most commonly installed thermoplastic single-ply membranes.
Thermoset membranes use principal polymers and are chemically cross-linked, vulcanized or cured, so they can only be bonded to similar materials with adhesives. They can’t be hot-air welded because it would change their physical characteristics. Thermoset membranes are compounded from rubber polymers. The most commonly used is EPDM [ethylene propylene diene monomer]. The membranes can come in unreinforced and reinforced. The reinforced helps resist tearing. EPDM is available in thicknesses ranging from 30 mils to 90 mils and comes in wider sheets like 50 feet by 100 feet. The wider sheets help if you have very big roof areas and can reduce the seams.
Other types include chlorosulfonated polyethylene (CSPE), epichlorohydrin (ECH), neoprene (CR), and polyisobutylene (PIB). Hypalon is another thermoset that is manufactured as a thermoplastic; but, because it cures over time, it becomes a thermoset. Hypalon materials are heat sealed at the seams, but with age, Hypalon can no longer be welded.
Some advantages to single-ply roofing membranes include:
Single-ply membranes are flexible sheets of compounded synthetic materials and not only give flexibility but also strength and long-lasting durability.
Ease of installation
TPO can be installed in a variety of ways and with the invention of peel-and-stick products, it takes less time to install. Like PVC and TPO, it is still hot-air weldable throughout its service life, which makes repairs and maintenance easier.
A single-ply roof membrane doesn’t need one of these big kettles to heat up bitumen. That allows for a cleaner and often faster installation.
Single-ply membranes are often lower in price, sometimes as low as $1.50 per square foot up to $10 a square foot or higher, but averaging $1.50 to $3 or $4. Some considerations that will affect the cost of the roof include:
- The amount of detailing or flashing
- The attachment method
- Insurance requirements
- Building and energy code requirements
- How much labor is needed
- The location of your building
- If it is a re-cover or tear-off
Generally, ballasted EPDM roofing systems have the lowest installed cost per square foot, followed by mechanically fastened, and fully adhered systems.
Since the single-ply roofing membranes are produced in a factory with strict control requirements that produces a consistent quality that minimizes the risk unlike the built-up roof systems.
Light-colored, reflective single-ply roof surfaces offer a significant reduction in energy use for your building. You may also be able to downsize your HVAC equipment or reduce its use which also saves energy.
In addition to the oils and polymers used to make an EPDM membrane, another ingredient is added to the mix to enhance UV resistance. With the white, acrylic coatings, titanium dioxide is typically used to reflect UV rays and prevent it from attacking the polymer. This makes a much cooler roof.
Single-ply membranes are lightweight and that can be important with some of the unique roof designs of modern architecture.
They perform well even with fluctuations in temperature, ultraviolet rays, and ozone. EPDM membranes are particularly respected for their long-term weathering ability.
Mechanically fastened single-plies will work on just about any type of roof deck.
Make sure there are enough fasteners because without enough fasteners it will increase the chances of blow-off, particularly if your building is exposed to high winds. If a fastener pulls out, its load is transferred to surrounding fasteners. This increases the chances of other fasteners also pulling out. The fully adhered applications (with mechanical attachment at the perimeters) tend to resist wind uplift better than those that are mechanically attached.
If your building is in a high wind area, you may want to avoid ballasted systems, or you need to take special precautions when designing and installing them.
PVC membranes are manufactured from PVC resin, stabilizers, pigments, fillers, plasticizers, biocides, and various processing aids, but unlike TPO membranes, which have to have additives to increase fire resistance, PVC membranes are naturally fire retardant.
Easy to Maintain
You can check to see if the membrane’s seams are intact and there aren’t any loose terminations or punctures in the field membrane or flashings. You should inspect it in the spring and fall or after any major storm. Check for any fasteners poking up through the membrane. Make sure to use the walk pads when making repairs and inspections.
The main disadvantage to single-ply roofing membranes include…lacks redundancy
We are talking about single-ply roofs, so that means you will be giving up the benefits and security of a redundant system. With a single-ply roof you should always take extra caution to avoid punctures and damage.
If you are considering a new roof but find yourself wondering, is a single-ply membrane roof system right for you, give our roofing experts a call at Kauffman Roofing in Jamesport. We are always happy to talk to you about your needs and your budget so we can make sure you get the roof that suits your building.