Understanding Metal Building Wind Ratings

Engineering Standards for Safe Construction

Aaron Williams

June 7, 2025

Weathervane atop an Indaco cupola.

When planning any metal building project, understanding metal building wind ratings is essential for ensuring both safety and code compliance. Whether you're constructing a commercial warehouse, agricultural building, or industrial facility, proper wind load engineering protects your investment and meets local building requirements. At Indaco Metals, we've engineered thousands of metal buildings to withstand significant wind forces, and we understand how critical proper wind ratings are for long-term building performance.

What Are Metal Building Wind Ratings?

Metal building wind ratings refer to the engineered capacity of a structure to resist wind forces without failure. These ratings are expressed in miles per hour (mph) and represent the maximum sustained wind speed a building can safely withstand when properly constructed and anchored.

Wind load calculations involve complex engineering that considers multiple factors including wind speed, building height, roof shape, and geographic exposure. Engineers don't simply design for straight-line winds – they account for uplift forces that try to lift the roof, lateral forces that push against walls, and the combined effects that create the most challenging loading scenarios.

The difference between wind speed and wind load is crucial to understand. A 90 mph wind rating doesn't mean the building will fail at 91 mph – it means the structure is engineered with appropriate safety factors to handle 90 mph sustained winds plus the dynamic effects and gusts that accompany severe weather events.

Professional engineering certification ensures that your metal building wind ratings meet or exceed local code requirements and provides the documentation needed for permits, inspections, and insurance coverage.

Local Wind Load Requirements

Building codes typically specify minimum wind speed requirements based on geographic location and local weather patterns. Most areas require buildings to withstand sustained winds of 90 mph, though some regions with higher wind exposure may require 100 mph or greater ratings.

Wind load requirements aren't just about the basic wind speed – they also consider factors like building height, roof configuration, and the surrounding terrain. A building in an open field faces different wind exposure than one surrounded by other structures or natural windbreaks.

Proper documentation of your building's wind rating is essential for obtaining building permits and passing inspections. Local building officials need to verify that your structure meets code requirements, and this verification relies on professional engineering calculations and certifications.

Insurance considerations also make proper wind ratings important. Many insurance policies require specific wind resistance standards, and buildings that exceed minimum requirements may qualify for reduced premiums.

Rigid Frame vs Truss Frame Wind Performance

Understanding how different structural systems handle wind loads helps you choose the right building type for your specific needs and local wind requirements.

Rigid Frame Wind Resistance

Rigid frame buildings excel in wind resistance due to their continuous structural members and moment-resistant connections. The solid steel beams and columns create a framework that distributes wind loads effectively throughout the entire structure.

This structural approach allows rigid frame buildings to achieve higher metal building wind ratings while spanning larger distances without interior supports. The continuous frame action means that wind forces applied to one part of the building are shared across the entire structural system.

Rigid frame construction typically starts at 30' x 40' x 10' and can accommodate much larger spans with excellent wind performance. The structural efficiency of this system makes it particularly suitable for buildings that need both large clear spans and high wind resistance.

Truss Frame Wind Performance

Truss frame buildings use a different approach to wind resistance, relying on the triangulated geometry of individual trusses to handle wind loads. Each truss acts as a discrete structural element, with wind forces transferred through the roof and wall systems to the foundation.

While truss frame systems can achieve excellent metal building wind ratings, they typically work best in smaller to medium-sized buildings. The individual truss elements are engineered to handle specific loads, and the system's overall wind performance depends on proper connection of all components.

Truss frame buildings offer cost advantages for many applications and can be designed to meet standard wind requirements effectively. They're available in standard widths from 20' to 60' and can achieve the 90 mph wind ratings required by most building codes.

Choosing the Right Frame Type

The decision between rigid frame and truss frame often comes down to building size, clear span requirements, and local wind conditions. For buildings requiring large clear spans in high wind areas, rigid frame construction typically provides superior performance.

Truss frame systems work well for smaller buildings and applications where interior columns aren't problematic. They can be very cost-effective while still meeting standard wind rating requirements.

Budget considerations play a role, but it's important to remember that proper wind engineering is an investment in long-term building performance and safety. The cost difference between frame types is often modest compared to the total project cost.

Factors That Affect Wind Ratings

Building height significantly impacts wind load calculations. Taller buildings experience higher wind speeds and greater dynamic effects, requiring stronger structural systems to achieve the same metal building wind ratings as shorter structures.

Roof pitch affects both uplift and lateral wind forces. Lower pitched roofs generally experience less uplift, while steeper pitches can create more complex wind flow patterns. The optimal roof pitch balances structural efficiency, drainage requirements, and wind performance.

Geographic exposure categories defined by building codes account for the surrounding terrain. Buildings in open areas face higher wind loads than those in suburban or urban settings with natural wind barriers.

Foundation design and anchoring systems are critical components of wind resistance. Even the strongest building frame won't perform properly without adequate foundation connections that can resist both downward loads and uplift forces.

Beyond the Basics: Additional Wind Considerations

Roof attachment systems must be engineered to handle uplift forces that can be substantial during high wind events. Proper fastening schedules and connection details ensure that the roof system performs as designed under wind loading.

Doors and windows require their own wind load ratings that should coordinate with the overall building performance. Large openings can create internal pressure that affects the entire structural system, making proper door and window selection important for overall wind resistance.

Regular maintenance helps ensure that your building continues to meet its designed metal building wind ratings over time. Loose connections, damaged panels, or deteriorated seals can compromise wind performance and should be addressed promptly.

Insurance benefits often accompany buildings that exceed minimum wind requirements. Many insurers offer reduced premiums for buildings engineered to higher wind standards, making the investment in superior wind ratings financially beneficial over the building's lifetime.

Working with Engineered Wind Ratings

Professional engineering is essential for achieving reliable metal building wind ratings. Proper wind load analysis requires specialized knowledge of structural dynamics, building codes, and local wind conditions that only qualified engineers possess.

At Indaco Metals, one of our key differentiators is having an experienced structural engineer on staff who reviews all building plans and designs custom solutions to meet strict wind resistance requirements. Whether you need a standard building kit modified for higher wind loads or a completely custom design for challenging conditions, our in-house engineer can create solutions tailored to your exact requirements.

This direct engineering support sets us apart from companies that rely solely on generic building designs. When you work with Indaco, you get the benefit of professional engineering review and custom design capabilities that ensure your building performs exactly as needed for your specific application and wind requirements.

Invest in Proper Wind Engineering

Understanding metal building wind ratings helps you make informed decisions about your building project and ensures long-term structural performance. Whether you need a truss frame building for cost-effective protection or a rigid frame system for maximum wind resistance, proper engineering creates buildings that stand up to challenging weather conditions.

Ready to discuss the wind rating requirements for your project? Our experienced team can help you understand local wind load requirements and choose the right structural system for your specific needs.

Contact us today to discuss your metal building needs:

Shawnee Location:

3 American Way, Shawnee, OK 74804

(405) 273-9200

Sand Springs Location:

17427 W 9th St, Sand Springs, OK 74063

(918) 419-6053

Or request an engineering consultation online to start planning your properly engineered metal building. With nearly 30 years of experience in structural design and manufacturing, we're ready to help you create a building that meets or exceeds your wind rating requirements.