Protect the Investment
Roofs are major investments in capital and manpower, and it’s important to protect that investment for the long term. Often, that means giving additional attention and investment to performance and durability upfront.
Even if a roof does not experience a severe weather event, it can still be punctured by windborne debris, a tool, a screw or the boots of HVAC or solar maintenance crews. When a roof is punctured, moisture can penetrate the system and cause materials within the system and even the structure to degrade. The additional durability supplied by cover boards can prevent these types of issues.
“All too often, roof discussions revolve around the membrane only,” Harriman says. “We must think about the deck, the slope, insulation layers, vapor barriers, air barriers and cover boards all performing in alignment with the membrane. A cover board is certainly a key component in many roof systems where durability and long service life are desired.”
Keeping moisture out of the assembly can even help maximize the life of the insulation. On average, insulation has about twice the life expectancy of a roof membrane. If moisture is kept out and the insulation remains intact, when a membrane needs to be replaced at the end of its life, a new membrane can simply be put over the existing insulation (subject to code provisions). If, however, moisture has intruded and insulation has been damaged, it will have to be removed and replaced.
The durability a good cover board provides protects all parts of the roofing system, including the insulation, while making the entire system more robust. Using a cover board helps preserve the insulation, lowers long-term costs for the owner, uses fewer materials and generates less waste.
Risk Reduction
No matter the environment or conditions a roof experiences, a good cover board adds an additional level of protection against impact, puncture, fire and other stressors that even a thicker membrane can’t provide.
A cover board mitigates risk against the stresses a roof will face. It helps the longevity of the roof and decreases the amount of maintenance it will require. Should the building face a catastrophe, like a major hailstorm or hurricane, a cover board will protect the roof from serious damage.
“I have investigated many roofs after severe weather events. It is always interesting to examine roof failures and look at adjacent roofs that held up to the same forces,” Harriman recalls. “One dramatic example occurred where the roof design on one building was amended by deleting [the] cover board on half of the roof because that half did not have any rooftop equipment and, therefore, had little need for roof traffic. The building was in what was then rated a Moderate Hail Zone. Unfortunately, a major hail event occurred and the half of the roof with cover board performed far better than the half of the roof with no cover board. All other parts of the system design were identical.”
Roof damage from severe hail can create a significant economic burden that goes beyond just the cost to repair or replace the roof. As an example, an average big box retail location can generate more than $100,000 per day in revenue, which then becomes lost for each day a building must be closed for repair.
No matter the building type or use, when looking at the big picture and examining the total life of a building, it makes sense to make upfront investments in items like roof cover boards to ensure continuous operation for the owner and occupants.
“A durable roof can positively impact both longevity and performance of a building,” Harriman says. “Reliability of service life and performance can be increased as risks are diminished.”
Very Severe Hail
The threat posed to buildings by severe hail is on the rise. According to data from the Insurance Information Institute, insurance claims related to hail have been steadily rising in the past two decades, averaging approximately $8 to $9 billion in damages between 2000 and 2013, and averaging between $13 and $14 billion in 2020 and 2021. It’s prudent to believe those costs and risks will only continue to increase in the coming decades.
The growing severity and impact of hail have led FM Global, one of the world’s largest property insurance companies, to adjust its loss-prevention data sheets. In the past, the sheets included classifications for Moderate Hail (MH) and Severe Hail (SH). In 2018, in response to the increase of hail-related claims from storms with hail more than two inches in diameter, FM Global added a Very Severe Hail (VSH) classification.
This step demonstrates the rising economic impact of worsening hailstorms and encourages more durable roof systems.