Written by Rocky Mountain Metal · Reviewed by Micah Hostetler, Owner · Based in Penrose, CO, serving Colorado.
Your building must be engineered to the snow and wind loads your county assigns to your parcel. Both change with elevation and terrain. They drive the framing, anchoring and fastening, and belong on your drawings and quote.
Key takeaways
- Two design inputs govern: the snow load and the wind load, plus how exposed your site is.
- The county sets them, the manufacturer engineers to them, and the drawings should show them.
- Snow load generally rises with elevation; wind exposure rises with open terrain.
- Drifting against taller walls and where roofs meet is designed for separately.
- The price of a steel building varies with snow load, so ask for the design loads in writing before you compare quotes.
What is snow load?
Ground snow load is the weight of snow expected on the ground at your site in a design-level winter. Counties publish it by location or elevation, and some require a site-specific check for higher sites.
Roof snow load is figured from the ground snow load, adjusted for roof slope, exposure, whether the building is heated and how it's used. Steeper, slicker roofs get some credit for shedding.
Drift and slide loads are added where snow piles up: against a taller wall, where a lean-to meets the main roof, or below a roof that slides onto another.
How it tends to play out across our service area:
- Arkansas Valley and eastern plains (Pueblo, La Junta, Lamar, Limon, Fort Morgan): generally lighter snow loads.
- Fremont County (Penrose, Cañon City, Florence): moderate.
- Higher valleys and mountain towns (Salida, Alamosa, and parts of the Western Slope around Montrose, Durango and Cortez): generally heavier, and rising with elevation.
The county's number for your parcel is the one that counts. Don't accept a quote engineered to a "typical" load.
What is wind load?
Design wind loads come from code wind maps. Much of Colorado east of the mountains sees strong wind, and some areas along the Front Range have special wind provisions.
Exposure describes the terrain: sheltered by trees and buildings, open with scattered obstructions, or flat open country. A parcel on an open ridge or the plains sees higher wind pressures than a lot in a treed subdivision.
What wind changes in the design:
- Steel frame size and anchoring to the foundation
- Wall and roof bracing
- The fastener pattern for roof and wall panels
- Connections throughout the frame
- Framing around large doors, which catch wind whether open or closed
See are metal buildings good in heavy snow and high wind? for how the building responds.
How do the loads change the building?
| Design input rises | What changes |
|---|---|
| Snow load | Heavier steel framing, closer spacing, stronger connections, drift design |
| Wind / exposure | Stronger anchoring, more bracing, tighter fastener pattern, stiffer framing at doors |
| Both | Cost, which is where high-country and plains quotes differ from in-town quotes |
What about frost and soils?
They're not loads, but the same department sets them and they matter for the foundation. Footing depth requirements vary by location and elevation, and some soils in southern Colorado shrink and swell with moisture, which affects foundation design. Some sites need a soils report. We'll walk you through what your county requires.
What should you ask before you sign?
- What snow and wind loads is this building engineered for?
- What exposure was assumed for my site?
- Are those loads on the drawings the county will receive?
- Was drifting at a lean-to or taller wall considered?
Where does Rocky Mountain Metal come in?
We look at your site and confirm the design loads for your location before the building is ordered. Every steel-framed building we sell through 1st Choice Metal Buildings and Carports is engineered to them. The manufacturer's crew from Texas installs it, and we oversee the project. Ask at your free quote visit anywhere in our service area.
Frequently asked questions
Can I find my snow load myself?
Often, yes. Many counties publish a table or map on their building department website. Elevation is usually the biggest driver, and we confirm the number before ordering.
Does a heated shop have a lower snow load?
Heated buildings get a small adjustment in the roof calculation, but the structure is still designed conservatively. Don't count on heat to solve snow.
Is wind or snow the bigger factor for me?
On the plains and in the Arkansas Valley, wind often governs. In higher country, snow often does. Many sites need to handle both.
Do these loads apply to ag-exempt buildings?
An exemption may waive the permit, not the weather. Every building we sell is engineered to its site's loads regardless of exemption status.
