Do Cool Roofs work?

cool roof with some water

What is a cool roof system?

Typically, a cool roof is white, or a light color and reflects the sun’s energy and UV rays. This reduces the temperature of the rooftop temperatures by as much as 60 degrees. Where a black or dark color roof absorbs the sun’s energy and UV rays and can create temperatures as high as 190°F during the summer. Dark roof surfaces contribute to the urban island heat.

What is the coolest roof material?

If you must install a new roof on your commercial building, the choices can confuse and overwhelming. There are many roofing materials types for commercial buildings, which one is the best all-around choice for cool roof purpose?  Here, we are listing 4 different roofing materials with the pros and cons of each, and which is the best for a cool roof result. 

EPDM (ethylene propylene diene monomer) 

EPDM roofing is commonly referred to as rubber roofing and is a common choice among commercial buildings because it is the least expensive of all options. It is lightweight, making it easy to install and doesn’t require the roof decking to be reinforced. This is a durable material that won’t scratch or scuff and has a life expectancy of a high-quality EPDM roof is 20 years.

EPDM is a black material and perfect for absorbing heat without being easily damaged by the sun’s UV rays. This makes a good product in colder climates, but not a good option for cool roof purposes.  EPDM is not aesthetically pleasing though with an inner tube look when rolled out. If your commercial building is a warm climate where the sun’s UV rays can heat a building up through the roof, this is not the material you need. It is not a cool roof material and can put a lot of strain on an HVAC system.

The drawbacks to EPDM are few but should be considered. It is also easily punctured by hail, tree branches, or a service technician that needs access to HVAC or plumbing pipes and vents found on commercial building roofs. It is easy to repair, but any puncture not noticed will allow water to infiltrate, leaving the possibility for major problems. It is installed with bond seas and if those seams are not placed right and the EPDM material doesn’t adhere well, water can infiltrate underneath the membrane.

TPO (thermoplastic polyolefin)

TPO is a popular option for commercial building owners because is inexpensive to install, even less than the previously mentioned EPDM roofing material. TPO is good for cool roof a white color that reflects the sun and minimizes the heat buildup inside a commercial structure, which is perfect for hot weather climates. It is lightweight and with several options for installation, makes it popular among roofing contractors.

It is resistant to breaking down, corrosion, algae growth, and mildew. With TPO, maintenance is minimized because pressure washing isn’t necessary. The seams are heat-welded, creating a bond that is more dependable between the seams, which is where most commercial building roof leaks begin. 

The drawbacks of TPO roofing start with the quality variances. Each manufacturer has different standards, which is why roofing contractors will always recommend going with a well-known brand name. The thickness of this material can vary also, which can lead to consistency problems, TPO’s top layer is a laminate, which can have weak points that cause cracking, crazing, deterioration, and shrinking. A major consideration for commercial business owners should be that TPO is not fire-resistant.

PVC (polyvinyl chloride)

Two layers are used to create a PVC roofing material with a reinforcement of polyester in between them. These layers have additives that make it flexible and UV-stable and prevent curing. It is durable, lightweight, and is fire resistant and resistant to chemicals and wind. Because it is heat-welded during installation, the sheets are permanently bonded at the seams. 

The biggest drawback is the expense. Over time, PVC shrinks, lifting the corners and pull the seams, which can lead to leaking. PVC is not the best for cold weather climate because it is prone to puncturing and shattering as its ages, which can be hard to repair. PVC has strong similarities to TPO but PVC has an upper hand with stronger resistance to chemicals and punctures.

SPF (spray polyurethane foam)

SPF roof coating starts off in a liquid form and is transformed into a solid as they apply it, expanding as it dries. This is a good roof coating for sustainable cool roof energy savings when applied in multi-layers with an acrylic roof coating. It is durable and strong, and the reflective topcoat makes it the cool roof coating a commercial building owner wants.

Proper maintenance and reapplying coating regularly, an SPF roof will last over 40 years. Because it seals cracks, crannies, and gaps, it makes airtight, cool roof and waterproofing systems. SPF roof coating is a good cool roof material because it provides a commercial building layer of insulation that saves on A/C and heat costs. 

This lightweight material will self-curb around protrusions and is often used to correct ponding water. The downsides to SPF roofing are the chemical reaction it has between two liquid compounds. With careful applications, it makes a good material, but careful calibration is needed while applying it.

What type of roof will last the longest?

By far, concrete, metal/steel, slate, or tile roofing materials last the longest of all materials used. Research finds these to last 50 years or longer. Next in line of lifespan, Built-Up roofing, asphalt shingled roof, or single-ply roofing, each estimated to last up to 30 years, depending on the climate and environment of the commercial structure. They estimate it a foam roof to last 25 years or longer while wooden shakes & shingles have a life expectancy of fifteen to twenty years.

It depends each on the climate and the environment and how they are installed and maintained. Manufacturing can affect longevity as well with each manufacturer having different procedures.

What color roof is the coolest? 

Dark color roof surfaces absorb the UV rays and the heat generated from those rays. For the typical flat or low slope roof on a commercial building, a traditional cool roof is all white, reflects the solar rays by as much as 50 percent or more. The use of colorants or pigments can create a nonwhite cool roof that will reflect the sun’s invisible, near-infrared radiation.

HVAC system on cool roof

Does cool roof paintwork?

 Cool roof paint is applied to roofs for better sun reflection, taking the strain off the HVAC system as it keeps the interior of buildings cooler and reduces the energy costs. Cool roof coating comes in an assortment of colors that are as reflective as the all-white roof coatings. The more reflective a roof it is, the less the harmful UV rays will impact the structure, keeping it cooler in the summer months.

Otherwise, a roof that doesn’t have any cool roof coating is subjected to the heat from those UV rays, heating the interior of the building. This causes the HVAC system to work harder and increases energy use.

The benefits a commercial building we have from installing a cool roof system are many. Here are the main ones:

  • Air conditioning needs are reduced, thereby reducing energy bills
  • Non-air-conditioned areas are cooler with a cool roof
  • Roof temperatures are decreased, extending the roof lifespan

A cool roof will do more than just cooling the commercial building. The environment benefits from a cool roof as well, especially in densely populated urban areas.  Which is better, a cool roof vs green roof?  A cool roof will remain cooler during peak temperatures. However, a green roof will have a longer lifespan, thus giving you more ROI for the initially higher costs for installing it. Dial 412-256-8050 today to get started on cool roof installation for your commercial property in Pittsburgh, PA.