Even though California doesn’t have hurricanes, strong winds can cause serious damage. As hurricanes are predicted to hit high-risk areas, this means the weather across the country will be affected, which means high winds could be in your area. With the uncertainty of what the weather will bring, now is the perfect time to get your commercial roofing prepared for dangerous winds.
The Importance of Commercial Roof Uplift Testing
What Is Uplift Testing?
The dynamic uplift resistance, or DUR, of a roof system, is determined by testing the resistance against outward pressure. The systems typically tested will include the roof materials, insulation, and fasteners, but not the deck. You need to understand this DUR rating in order to best choose the roof assembly that will stand up to the wind pressures in your area. The uplift that must be resisted is calculated using the height of the building, roof style, type of occupancy, and geographical location.
There are several protocols used to evaluate wind uplift resistance. Typically testing is done using a cup-shaped rig, placing the open end on the roof. The test then starts, acting as a vacuum, removing atmospheric pressure to generate suction that lifts the roof. The rating given to the system corresponds to the suction. You can use this rating to evaluate if additional support is needed to stand up to winds. Uplift testing also helps to identify any weak spots in the roof, so that roofers and construction crews can take care of these before serious damage occurs.
What is Wind Uplift?
Daniel Bernoulli, a Swiss mathematician, discovered that the faster liquids move, the lower the pressure is. This effect is also seen when strong winds tear off portions of a roof. The presence creates an obstruction to natural winds and airflow moving across the globe, and as the wind moves around the building, the pressure on the building surface will change.
- The direction of the airflow is linked to the pressure in a few ways.
- On wind-facing surfaces, there will be positive pressure.
- On leeward surfaces, pressure will be negative.
- At eaves, corners, and rakes, pressure is negative.
Wind uplift is generated when the pressure under the roof is greater than that above and it can increase as winds get stronger and during storms. With high winds, air enters the building, essentially inflating it, which causes the pressure under the roof to increase. At the same time, the air moving quickly outside the building is reducing pressure from above. This can cause stress to the building structure. As uplift increases stress on the building, materials weaken which can lead to serious damage. If the uplift is greater than what the building was designed to withstand, fasteners can be pulled free, and sections of roofing can be torn and even removed. To help prevent this, building engineers must follow building codes with regard to uplift ratings.
The Uplift Testing Process
The best time to perform uplift testing is after roof installation and before building construction is completed. Testing will be done using codes that best represent the region and all results must meet or exceed these codes and standards for the roofing to be deemed safe to withstand strong winds. It is also good practice to have uplift testing done every 7 to 10 years in case there has been any degradation along the way that could make the roof more vulnerable to high winds.
When it comes to high winds and storms, there is no one location that is exempt. Safety is essential when it comes to commercial properties, and uplift testing is the best way to make sure your roof stands up to any winds blowing through. Uplift testing lets building owners better understand how resilient their roofing system is and when it needs additional support or repair. Reach out to us today with any questions or concerns you may have about uplift testing and the safety of your commercial roof.