Understanding Wind Ratings for Metal Buildings in Utah
When designing a pre-engineered metal building (PEMB), wind isn’t just a weather event — it’s a structural load. And in Utah, with its mix of valleys, canyons, and open plains, wind ratings play a critical role in both code compliance and long-term performance.
Whether you’re building in Salt Lake, St. George, or the Uintah Basin, here’s what you need to know about wind ratings, how they’re determined, and why they matter for your PEMB.
What Is a Wind Rating?
A wind rating refers to the design wind speed — typically expressed in miles per hour (mph) — that a building must withstand without structural failure.
For metal buildings, this affects everything from:
The size and spacing of steel frames
The number and type of anchor bolts
Roof panel fasteners and edge flashing
Door bracing and eave struts
Most wind ratings are based on 3-second gust speeds, not sustained wind. That means your building must resist sudden, high-pressure gusts — not just average breezes.
Utah’s Wind Zones: Why They Vary
Utah isn’t flat — and wind speeds vary dramatically by region and elevation. The International Building Code (IBC) and ASCE 7 standard map the state into different wind speed zones.
Some examples:
Salt Lake Valley: Typically rated for 115–120 mph
Western Utah (open terrain): Often rated at 120–130+ mph
Mountainous areas or canyon mouths: May exceed 135 mph
Local jurisdictions often adopt site-specific amendments to these ratings based on historic wind events and microclimates — which is why a PEMB in Lehi may have a different spec than one 30 minutes away in Spanish Fork.
Exposure Categories: The Terrain Factor
Wind doesn’t hit all buildings the same. That’s why PEMB wind design also considers exposure categories:
Exposure B: Urban or suburban areas with buildings or trees that reduce wind
Exposure C: Open terrain with few obstructions (typical in many Utah rural areas)
Exposure D: Flat, unobstructed areas next to open water (less common in Utah)
Most metal buildings in Utah are designed to Exposure C unless protected by dense development or topography.
Components Affected by Wind Rating
Every increase in required wind speed impacts your PEMB design, including:
Steel frame size: Heavier columns and rafters
Roof purlins and wall girts: Closer spacing or deeper members
Wall and roof panels: Higher gauge or additional fasteners
Endwall bracing: Diagonal braces or portal frames
Doors and windows: Wind-rated units with reinforced framing
Skipping this step or underestimating wind loads can lead to serious performance issues — or even code violations.
How Wind Ratings Impact Cost
Higher wind ratings = more steel, more engineering, and more labor.
While it may not be a massive increase, here’s how wind loads can drive cost:
Heavier framing = more material + larger foundations
Tighter spacing = longer erection time
Upgraded fasteners = more detail work
That’s why it’s critical to design your PEMB to match the actual site conditions — not just use a generic or low-end spec to save on up-front costs.
Getting It Right: Coordination with Your Contractor
Before submitting for permits, make sure your contractor:
Pulls local jurisdiction requirements (not just statewide defaults)
Verifies site-specific wind speed and exposure
Coordinates with the PEMB manufacturer to ensure compliance
Accounts for accessory items like doors, HVAC roof curbs, or signage that may require additional bracing
At A.D. Constructors, we handle this entire process — whether you’re building a warehouse, shop, or industrial facility — to make sure your structure is safe, compliant, and engineered for the long haul.
Final Thoughts
Understanding wind ratings isn’t just for engineers. As an owner or developer, knowing how these ratings affect your PEMB can help you:
Make informed decisions
Avoid surprises during permitting
Get a safer, more durable building
And in Utah’s unpredictable climate, designing for wind is non-negotiable.
👉 Have questions about wind loads or PEMB design? Let’s talk!