Commercial roofing contractors: you may get into a habit when selling roofs of always relying on the same materials. Asphalt, mod bit, TPO, standing seam. But there are many great flat roofing options out there that may be the right fit for your customers.
This blog is your guide to EPDM roofing (ethylene propylene diene monomer roofing), whether you're brand new to it or just need a refresher. If you're doing research or comparing material options, here's a great place to start. We'll cover:
- What EPDM is
- Pros and cons of EPDM for roofing
- Different installation methods
- Costs compared to other materials
What is EPDM (ethylene propylene diene monomer) roofing?
EPDM stands for ethylene propylene diene monomer roofing. Yeah, it's a bit of a mouthful, so we'll stick with EPDM. This material is a type of synthetic rubber.
Natural rubber comes primarily from the latex in Hevea Brasiliensis trees (or Para rubber trees). These are native to the Amazon rainforest. Natural rubber is not a hardy material. It doesn't withstand harsh temperatures, chemicals, or oils. Basically, natural rubber isn't strong or resilient.
EPDM rubber is made by combining three different chemical building blocks (monomers) – ethylene, propylene, and a diene component – through chemical reactions. The result is a rubber material that is resistant to UV radiation and can last outdoors for upwards of 30 years.
A quick history
People have used rubber for thousands of years in different ways. Rubber boomed in the 1880s, though, with the need for rubber tires for bicycles. Then, when the automotive industry took off and tires expanded, the need for rubber boomed again.
EPDM was created in the 1950s to meet the demand for rubber as the boom continued. EPDM was made to be like natural rubber but can withstand heat, chemicals, and other harsh elements. Its invention diversified the use of rubber in a lot of ways. Industrial respirators, radiators, garden hoses, gaskets, washers, o-rings, and electrical tools all utilize EPDM.
In the 1970s, the cost of asphalt shingles went up because of the oil embargo. EPDM was used to create an alternative roof material.
EPDM for roofing
This roofing system started being used as a roofing material in the 1970s when an oil embargo drove up the cost of asphalt shingles. The rubber is rolled into sheets that are laid out and attached to roofs. It's great for large, flat roofs like commercial properties.
EPDM is an excellent option for flat or low-slope roofs on:
- Commercial buildings
- Detached garages or carparks
- Certain sheds
- Porches or entrance covers
- House extension roofing
It can also be used for:
- Rubber gutter lining
- Balcony flooring
- Green eco-roofs
Pros and cons of EDPM roofing
Like all roofing materials, the EPDM membrane roofing system has its own pros and cons.
Benefits of EDPM
EPDM roofing brings tremendous value for property owners who are looking for functional and low-cost roofing solutions. Here are some of its main benefits:
- Super long lasting — it can last up to 30 years.
- Lightweight — the material isn't really heavy and rolls out without adding much weight to a building. It weighs about a half pound per square foot for a 60 mil, fully-adhere, membrane-only EPDM.
- Low risk of leaks — The long sheets are rolled out and have fewer seams that can leak.
- Easy to install — Roll it out and adhere it to the roof.
- Hail resistant — EPDM is rubber, so hail stones bounce on it.
- Ozone resistant — Ozone resistance refers to the ability of a material to withstand exposure to the ozone, i.e. oxygen. EPDM has an ozone-resistant rating of 'A' up to 100°F.
- Commercial properties are ideal candidates for rubber roofing for two reasons: the rooftop is usually not seen by the public, and it doesn't need much maintenance or repair.
- Cost-effective — It's lower cost than other roofing materials, which is great for large installations.
- Base-layer material — EPDM can be used as a base if you want to add a rooftop garden, solar array, or another rooftop feature.
- Color variations — This material is available in white or black. For commercial properties in the south, a white EPDM roof can lower your air conditioning costs and reduce your impact on urban warming.
Disadvantages of EPDM
The pros of EPDM outweigh the cons. But it's not perfect for every use case, so be aware of the downsides, too.
- Prone to damage — These sheets aren't very thick and, while resistant to hail and weather, can tear or be punctured with sharp objects. Branches, rock, or other debris can damage the roof.
- Shrinkage — Since EPDM is installed in long rolls, any shrinking of the material compromises the entire roof.
- Seam failure — Although there are fewer seams than other roofing materials, there's still a chance of a seam leak with EPDM. If that happens, again, the entire sheet may need to be replaced.
3 ways to install an EPDM roof
There are 3 main methods used for installing EPDM:
1. Adhered
The rubber roofing is completely glued onto the roof sub-surface. This installation process is the most time-intensive, but the end result is also the highest-quality EPDM roofing solution. It's also a more expensive installation option than some faster methods.
2. Attached mechanically
This method is when sheets are attached to a roof with latches, fasteners, or screws. This is the most common installation method and doesn’t take very long.
3. Ballasted
A ballasted method of installation is when the sheets are laid down and then "ballasted" to hold it down; no anchors or adhesives are used. Typically, gravel is used to hold down the EPDM, but stones or sand work too.
Cost breakdown
Here's how the USD cost of EPDM roofing compares with some other popular roofing options. We've listed both commercial and residential materials here for easier comparison:
- EPDM: $6 to $12 per square foot
- Mod Bit: $6 to $12 per square foot
- TPO: $7 to $15 per square foot
- Standing Seam Metal: $15 to $25 per square foot
- Asphalt Shingles: $3.50 to $5.50 per square foot
- Tile: $10 to $14 per square foot
- Slate: $20 to $25 per square foot
Overall, EPDM is one of the more cost effective flat roofing options on the market, and even viable for some or partial residential projects.
Another option for your customers
There are a wide range of benefits and use cases for ethylene propylene diene monomer roofing. It's a real contender for commercial properties — and can even be used on some residential roofs if they have flat or low-slope roofs.
Keep EPDM in mind when pitching a roof to both commercial and residential customers, and feel free to use this blog to help educate them on the pros, cons, and use cases of this roof material.