Protecting data centers: the importance of roof cover boards

What are the key challenges facing data center roof assemblies?

Data center roof assemblies are subjected to numerous stresses that demand high-performance solutions.

Wind

Wind flowing over the building creates areas of positive and negative air pressure that result in different forces exerted on its structural elements. Wind uplift attempts to pull the roof off the building, with forces becoming particularly extreme at the corners and on the perimeter.

Building codes and engineering groups such as the American Society of Civil Engineers set wind performance standards measured in miles per hour. They vary significantly by location, for example inland locations may require a 90 mph rating, while coastal areas — known as High-Velocity Hurricane Zones — require a rating over 200 mph. DEXcell Roof Boards provide the rigidity needed to distribute this wind load across the roof surface, offering superior wind uplift performance that often makes them a requirement in high-wind regions where other options are insufficient.

Fire

The threat of fire can come from both outside and inside a data center. Embers from adjacent burning structures or wildfires can land on the roof. Conversely, a fire starting within the facility could spread up into the data center roof assembly. All DEXcell products meet Class A and Class 1 fire ratings, and the 5/8" boards can help achieve 1- or 2-hour fire-rated roof-ceiling assemblies. The inherent fire resistance of the gypsum and cement in DEXcell products significantly enhances the roof’s overall fire performance.

Hail

Using roof cover boards on data centers can reduce hail damage to the roof membrane and the underlying insulation. DEXcell FA VSH® Glass Mat Roof Board is specifically designed for single-ply systems in hail-prone regions.

Human traffic and impact

Data center roof assemblies see frequent visits from mechanics and technicians servicing HVAC units, generators and chillers. Despite designated walkways, foot traffic across the membrane is common and can degrade the insulation over time. Dropped tools can also dent and puncture the membrane. DEXcell Roof Boards offer superior compressive strength (700–1100 psi) compared to high-density polyiso (80–150 psi), protecting the membrane and insulation from foot traffic and impact.

Equipment weight

Heavy rooftop equipment, including HVAC units and the solar array racks, can crush the underlying assembly when not properly supported. A hard coverboard keeps the insulation from being damaged under this significant weight.

Thermal spikes

The waterproofing membrane on a low-slope data center roof assembly is in a constant battle with rapid temperature fluctuations. The shift from direct sun to cloud cover causes molecular degradation, making the membrane brittle and prone to cracks and leaks. Rainwater pooling in divots, such as those caused by foot traffic or dropped tools, can act like a magnifying glass, concentrating heat on the membrane. Unlike insulation-based coverboards that can trap heat in the membrane, gypsum and cement-based DEXcell products act as heat sinks. They absorb intense heat from the membrane and release it slowly, buffering against extreme temperature spikes and increasing the membrane’s longevity.