Roofing Systems

Ethylene Propylene Diene Monomer is a type of single-ply membrane that consists of a synthetic rubber compound that allows it to be flexible. EPDM has been used on commercial roofing facilities since the 1960s and is considered a time-tested option. Although EPDM has more of a trusted history with commercial roofing, it only has about 20% of the commercial roofing market according to the NRCA.

With EPDM, you have an option of choosing from a variety of thickness 45, 60, or 90 milliliters and either black or white for the color. While TPO has a natural white color, EPDM usually results in a dark gray or black color for your commercial roof. While the darker color is not helpful in reflecting UV rays, it does retain heat and can be useful in cooler weather.

In today’s current economy, business owners and managers face the stressful task of keeping their commercial facility running safely and in presentable condition. The most crucial system in a commercial building is the roofing system.  It's wise to research the the advantages and disadvantages of a single-ply membrane roofing system.

At M&M Roofing & Repair, we have over 40 years of commercial roofing experience. We provide our expert knowledge to our clients to decide what kind of roofing system is ideal for their commercial facility.

While the choice is ultimately up to the building owner, we would like to point out a few pros and cons to Single-Ply Membrane Roofing Systems.

KEY POINTS 

1. Single-Ply Membranes are sheets of rubber and other synthetics that can be ballasted or chemically adhered to insulation to create a layer of protection for your commercial facility roofing system.
2. There are two main types of single-ply membrane commercial roofing: Thermoplastic Polyolefin (TPO) and Ethylene Propylene Diene Terpolymer (EPDM). They mostly differentiate in their chemical makeup, how they are installed and their energy efficiencies.

PROS

• EPDM roofing has been used by commercial flat roofing experts for over 60 years. The amount of time this has been on the market has allowed various laboratories and field studies to be performed and tracked. This is why single-ply membrane roofing has a proven track record for being a high-performance roofing option.

• TPO, has more of a market share than EPDM does, though TPO has not been on the market as long as EPDM has. This concludes that a TPO single-ply membrane roofing system is still under immense testing and constantly evolving into a more reliable commercial roofing membrane.

• Single-ply membrane commercial roofing does not include the insulation factor, as a client you have a variety of options to select from to insulate your commercial facility’s roof. There are multiple types of insulation options the facility manager/owner may choose from:

• Polyisocyanurate (Polyiso) – This is the most commonly used insulation type for commercial roofing system applications, Polyiso is more expensive but, the pay off with an even higher R-value rating. 

                   (The R-value is a measurement of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat.)

• Expanded Polystyrene (EPS) – This insulation has the highest R-value per dollar, EPS is mainly used for roofing, wall and floor insulation. EPS can be used for ground contact and does not retain water over time.

• Extruded Polystyrene (XPS) – This insulation is usually defined by the blue, green or pink color, XPS falls in-between Polyiso and EPS in the variables of price and performance. XPS is semipermeable with a perm rating of 1.

                  (Perm Rating is the standard measurement of the water vapor permeability of a material. The higher the number, the more readily water vapor (in the gaseous state) can diffuse through the material.)

• TPO is the fastest growing single-ply membrane in terms of popularity across the commercial roofing market. It is also known as “White Roofs,” TPO is usually manufactured white and highly reflective. TPO also has other various options available such as: tan, gray, green, blue and red.

• EPDM is commonly described as “Black Roofs,” due to the natural dark color of the single-ply membrane. This high-performance rubber compound provides excellent weatherability and heat retention beneficial for commercial facilities located in climates with lower “cooling days”.

• Compared to the other complexities involved with processing spray polyurethane foam roofing, installing a single-ply roofing membrane roofing is relatively simple.

• After the existing substrate is prepared, either by cleaning or removing the existing roof, the new insulation layers are properly installed and covered by a cover board.

• There are three main ways to attach the membrane to the cover board: ballasted, with an adhesive or mechanically fastened to the insulation.

• The main significant difference between TPO and EPDM single-ply membranes comes down to the time it takes to adhere the membrane seams together. TPO uses a specialized welder specifically for the purpose to melt down the membrane at the seams and fuse them together. EPDM is fused together using seam tape.

• When there are multiple layers, you have the option to choose the thickness of the single-ply membrane installed on your roof. Single-ply membrane roofing is very lightweight compared to other commercial flat roof systems. This helps relieve the stress that’s put on your building’s foundation.  (This Excludes ballasted systems)

• The overall flexibility of single-ply membranes allows our flat roof experts to help accommodate unique roof designs. Flexibility also allows the commercial roofing systems to stay intact with expanding and contracting buildings.

CONS

• Single-ply membrane roofing is very lightweight and flexible, this leads us to our first con, the thin layers are easily punctured.

• Single-ply membrane roofing does not usually have a hard-top layer to protect the synthetic rubber against dropped tools, gravel or loose screws from being pushed into the rubber membrane. This kind of damage could possibly create holes and tears in the rubber and insulation and possibly be vulnerable to leaks.

• Usually commercial roofing systems have various accessories attached such as A/C units, skylights, air vents, plumbing vents and much more. Penetrations like this on a roof can instill various obstacles for the flat roof experts to be able to roll out a straight section of single-ply membrane.

• Our flat roof experts tackle these penetrations with single-ply membrane roofing, they need to usually cut a smaller piece of membrane to size and essentially building up the roof around the vents/units which takes up much more time and effort. This is to ensure our experts can waterproof the roof around its obstacles that they may propose.

•  Above we covered in the installation explanation how the rubber membrane is rolled out, overlapped and fastened with either heat, mechanical fasteners, adhesives or tapes. Even when the seams are sealed, they are more vulnerable to leaks than other roofing systems. 

• The sun's UV rays directly shine on the roof which can degrade the adhesives quickly over time. This is what usually makes the  seams more vulnerable to leaks. If there’s a puncture, tear or other damage to the roof, the UV rays coming into the adhesive layer can cause more damage with the adhesives deteriorating.

• Single-Ply Membrane Roofing Systems can usually take up over half of the roofing systems for commercial, industrial, and manufacturing facilities that are looking for a more sustainable, economically efficient option.

At M&M Roofing & Repair, our goal is to get you a long-lasting roofing system that’ll protect your facility for the foreseeable future. This includes working with our flat roof experts to help you choose the best roofing systems to meet your specific needs.