Roofing is probably not the first thing on your mind when it comes to managing a data center. Usually, the logistics of cooling the servers and facility precedes matters of choosing a roofing material. However, the right data center roofing can, in fact, make a difference in temperature and climate control, saving you money in the long run and warding off potential catastrophes. Material, shape and even color all contribute to how effective a roof is for this purpose. A commercial roofing contractor can help you determine what the ideal roof looks like.
Why the Roof Matters
Large data centers get hot quickly because of the number of servers running — besides being an unpleasant environment, this heat is an issue for keeping those servers functioning. This isn’t the only source of heat to worry about, though: heat from the sun’s rays is also absorbed through the roof. On a summer day in a warm climate like California or Texas — where many data centers in the U.S. are stationed — a flat asphalt roof could get as hot as 150°F. Many standard roofs dissipate heat slowly as well, whether because of the materials or poor ventilation, leaving that heat trapped even when the sun goes down.
Because of this behavior, the roof is one of the most significant factors to consider for cooling solutions, following air conditioning and other cooling systems.
How Your Roof Affects Temperature
A number of factors determine the extent to which the roof influences the temperature inside your building. Color is often the first to come to mind — all else being equal, darker colors absorb more light, and therefore more heat, while lighter colors reflect more light and heat. The finish of a surface contributes to this as well, naturally.
Another major factor is the material used and how well heat permeates through it. Traditional asphalt roofs are notorious for how much heat from the sun they absorb. Besides reflecting light poorly, asphalt also traps heat because of its low conductivity. Metal roofing, on the other hand, does not trap heat well; though metal is quick to heat up, it also releases that heat quickly as the sun goes down. Materials that are both reflective and weak conductors for heat provide the best protection.
The slope of the roof affects how readily it catches sunlight. A flat roof catches more sunlight throughout the day than a steep-sloped roof. For many commercial buildings, flat roofs are often more feasible than steep slopes because of ease of construction.
Finally, installing sufficient ventilation on the roof — as well as in the space underneath it, if it exists — helps to expel absorbed heat.
How To Create a Cool Roof
A cool roof is a roof specifically designed to maintain a lower surface temperature compared to a traditional roof. Green certification programs consider a roof to be “cool” based on how well it reflects sunlight and releases absorbed heat — solar reflectivity and emittance, respectively. Commercial roofing contractors can build cool roofs using a number of highly reflective or emissive materials.
- Some single-ply membranes can function well for cool roofing on low slopes. Thermoplastic polyolefin (TPO) is highly reflective; ethylene propylene diene monomer (EPDM) reflects poorly by default but can be improved with a titanium dioxide-based coating.
- Built-up roofing (BUR), composed of layers of asphalt, fabric and gravel, is an inexpensive standard but typically doesn’t rate well as a cool roof. Using reflective marble or gravel chips improves its effectiveness.
- Metal roofing is highly reflective and often comes painted for an improved finish. This works for both flat and steep-sloped roofs.
- Tiles made of clay, slate or concrete can be naturally reflective depending on composition, or they can be treated with a reflective coating. This is only an option for steep-sloped roofs, though.
Alternatively, for existing “hot” roofs, contractors often apply elastomeric cool roof coatings for a more reflective surface, with improved durability as a bonus. This can also be done with untreated building materials during installation. Don’t try this with pre-existing asphalt or built-up roofing, though, as it can compromise water resistance.
Other Data Center Roofing Issues To Consider
Besides reflecting and emitting heat well, you want your roof to be made of sturdy materials. This is especially true when you consider the significant heat and humidity in a data center. Thermal and moisture resistance are crucial; fortunately, most cool roofing materials are chosen for being resilient.
The roof should also allow water to drain off the sides — a low-sloped roof with poor drainage runs the risk of retaining standing water. While roofing materials and cool coatings are designed to hold up against moisture, standing water is a different matter. This can shorten the roof’s life span or damage its coating.
Consulting with a roofing contractor is an important step in designing and building a data center — it means better cooling, lower energy bills and less risk of damaging servers. Benton Roofing provides effective and comprehensive roofing solutions for data centers and other commercial buildings, whether you need a new roof or a touch-up to your current one. Call us at (888) 622-1622 for more information, or use our website to request a quote today.