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How to Read Wind Pressure Tables
Watch as we navigate a real pressure table step-by-step. By the end, you'll know exactly which number to use for your project.
| Zone | Location | Positive (+) PSF | Negative (-) PSF | Use For |
|---|---|---|---|---|
| 1 | Roof Field | +22.5 | -38.2 | Center of roof |
| 2 | Roof Edge | +22.5 | -52.6 | Roof perimeter |
| 3 | Roof Corner | +22.5 | -67.4 | Roof corners |
| 4 | Wall Field | +42.1 | -48.3 | Wall center |
| 5 | Wall Corner | +42.1 | -67.4 | Wall corners |
Step 1: Find Your Zone
First, identify which zone your window, door, or component is in. Zone 5 (wall corners) has the highest pressures.
Understanding Pressure Tables
Pressure tables are like a cheat sheet for your building. Instead of doing complex math, engineers create these tables that tell you exactly how much wind force each part of your building will experience.
The table shows two types of pressure: positive (wind pushing in) and negative (wind pulling out). Think of positive pressure like someone pushing on a door, and negative pressure like a vacuum cleaner trying to suck off your roof shingles.
Pro Tip: Always Use the Bigger Number
When buying windows or doors, give your supplier BOTH the positive and negative values. They'll use the larger magnitude (ignore the minus sign) to select products that can handle forces in both directions.
In Monroe County, Florida, these numbers are especially high because of hurricane risk. A Zone 5 corner at -67.4 PSF means the suction force on a 3-foot by 5-foot window is over 1,000 pounds trying to pull it out of the wall!
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