Two of the most popular types of commercial roofing are EPDM and TPO roofs. Both use a membrane that is rolled out onto a flat or slightly peaked roofs. They each have their advantages and disadvantages. Fortunately, here’s the definitive short guide that will help you decide which type of roof is best for your needs.
Ethylene propylene diene monomer (EPDM) roof has been the standard commercial roof over 50 years. Its durable rubber membrane meets the needs of many industrial and commercial buildings. EPDM is made from a mix of recycled tires, sawdust, and slate dust. Of the two types of roofs, EPDM is a bit more expensive.
The roof is typically stripped bare to the wood. Then an adhesive is put on the roof. The EPDM material is then rolled out onto the building. Because there are few seams and they’re sealed with adhesive, there’s little risk of leaking. There are also fasteners that can be added to areas that are too hard to glue. Some roofs will be ballasted with stone to improve the appearance and help to keep the membrane in place.
EPDM Quick Facts
- Lasts 25 to 30 years on the typical commercial roof
- Is mechanically and adhesively fastened
- Seams are fused with seam tape
- Only comes in black
- Retains heat from the sun
- Excellent against hail
- Easy to repair as no electricity is needed
The biggest drawback is that EPDM roofs retain a lot of heat. This can increase energy costs in the summer. The largest advantage is that it can withstand a lot of punishment from hail, which is a big problem here in Denver, CO.
Thermoplastic polyolefin (TPO) is a similar roofing concept, a material that’s rolled out onto a roof over an adhesive. While the name says plastic, this is also a type of rubber. Again, the roof is stripped, and adhesive is spread over it. Then the membrane is rolled out and adhered to roof. Seams are heat-sealed, often requiring an electricity source.
Since it’s available in white, gray, and black, this type of roof can reflect sunlight. That can save a lot of money on cooling in the summer. This also helps the air conditioners on your roof to work more efficiently since the intake air is not quite as hot. You might talk to your air conditioning contractor to find out if the cost savings is a significant factor.
There are also some parts of the country that require light colored roofs whenever practical. Cities like New York make it essentially mandatory to install a sunlight-reflective roof to reduce the heat sink effect of the city.
The biggest drawback is not really an issue with a good roofer or a reputable company, such as Water Restoration. There are many companies producing different version of TPO depending of the specific blend of materials, this has meant that some inferior products have hit the market. While they all have the same name, there are a variety thicknesses and durability. Make sure that if you choose to have a TPO roof installed that you get a reputable contractor to make sure you get top of the line product.
While TPO can withstand hail damage, it’s not quite as durable as EPDM. The surface of TPO is laminated. When hail hits it, it can develop concentric circular cracks. This might ultimately compromise the roof’s integrity. This is less of an issue if the quality of the material is high.
TPO Quick Facts
- Last 15 to 20 years on a commercial roof
- Chemically adhered to the roof
- Seams are fused with a hot-air gun
- Available in white, gray, tan, and more.
- Reflects sunlight, reducing energy costs
- Less expensive
The biggest con for TPO roofing is that last about 5 to 10 years shorter than EDPM. The biggest advantage is that’s often much less expensive.
How to Choose Between EPDM and TPO Roofing
Making a choice is usually a matter of your plans, weather and geography.
If you plan to install solar panels, most roofers recommend EPDM. It’s a bit easier to reseal once you’ve made holes to make an installation.
Weather can be important. EPDM is more resistant to hail. That’s an advantage in places like Denver where Denver Water Restoration is located. We have a lot of hail and it damages roofs every year. Since both roofs can be mechanically fastened, they are fine for cold weather regions.
If you’re in a place that gets a lot of sun, you might consider TPO. It’s ability to reflect sunlight can save a lot of money on energy bills. In fact, some areas require that you have a reflective roof.
EPDM & TPO Versus Other Roofing Systems
EPDM and TPO are so popular for flat roofs or roofs with a slight slope because they last much longer and will remain waterproof for years.
No roof is every really 100% flat. There will always be areas that collect water and ice. If you choose, for example, a shingle roof, the water will get up under the shingles quickly and create a leak, damage, rotting, or rusting. Shingles are great for peaked roofs, but on a flat roof, you need a membrane to keep things dry.
Most cities have pitch requirements for shingle roofs. It’s worth checking into before you look for the right type of roofing materials for your building. Unlike a metal roof, you won’t need to reinforce the roof joists and trusses; these roofing materials are very light in comparison.
Still Can't Decide?
If you’re still not sure, you should speak to a roofing contractor. If you're in the Denver area, you should talk with the Denver Water Restoration Roofing Division. We can help you make the right choice for your building and will make sure you get the best price for the work.