Design pressure rating
A design pressure rating is the positive and negative wind load, measured in pounds per square foot (psf), that a skylight is tested to withstand without failing. It tells you how much pressure the unit can take from wind pushing on it or pulling away from it.
A design pressure rating is the wind load a skylight has been tested to resist, expressed in pounds per square foot (psf). It is listed as two numbers: a positive value for pressure pushing inward on the glazing and a negative value for suction pulling outward. Wind moving over a roof creates both, and the negative side is often the larger concern because uplift can lift a skylight out of its curb.
The rating comes from standardized testing of a complete unit, including the glass or glazing, frame, flashing, and the way it attaches to the roof. A manufacturer's rating applies only to the tested configuration, so changes in size, glazing, or mounting can change the number.
The rating matters most in places where wind loads are high. Coastal and hurricane-prone areas such as Citrus County require units with ratings that match local design wind speeds and building code requirements. A skylight with too low a rating can leak, crack, or be displaced in a storm, and the installer and building inspector will check that the listed psf values meet the requirement for the roof and location.
When you compare skylights, the design pressure rating is one of the first specifications to confirm, alongside the product's test documentation. Homeowners and contractors looking for installers who work with impact-resistant or wind-rated products can start with the storm and hurricane rated providers listed in this directory.
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