Larimer County Structural Design Criteria for Garage Door Specifications

Larimer County covers a wide range of terrain, from the plains of Fort Collins at 5,000 feet to mountain passes above 12,000 feet. Wind speeds in the county span from 115 mph at the urban core to 225 mph at exposed mountain sites. That range makes the county's structural design information the essential starting point for any garage door project in the area.

What this source says

Larimer County's Building Department publishes a Structural Design Information document, updated January 2026, that provides design criteria for building permits in unincorporated Larimer County. Many municipalities in the county (Fort Collins, Loveland, Berthoud) also reference this document as a baseline.

This document provides climatic and geographic design criteria for Larimer County. Values include ground snow load, wind speed (Vult), exposure category, frost depth, and seismic design category. Snow load values are based on SEAC 2016 and must be multiplied by 1.6 when used with ASCE 7-22.

Key values for common Larimer County locations:

Fort Collins (urban core, ~5,000 ft elevation): - Ground snow load: approximately 30 psf (SEAC 2016) x 1.6 = 48 psf design value under ASCE 7-22 - Vult: 115 mph - Exposure category: B or C depending on site

Mountain and foothills areas: - Ground snow load increases significantly with elevation; values over 100 psf (SEAC 2016) are found above 8,000 feet - Vult: up to 225 mph at exposed mountain ridges and passes within the Special Wind Region

County-wide constants: - Frost depth: 36 inches - Seismic Design Category: B (most of county); confirm for specific sites

When it applies

Fort Collins and Loveland garage door projects. At 115 mph Vult with Exposure B or C, a standard residential garage door in Fort Collins needs to meet a design pressure of about 16 to 22 psf. The range depends on opening size and site exposure. Most major residential door brands cover this with standard products.

Mountain properties in western Larimer County. Communities near Estes Park and along US-34 face much higher design wind speeds. Estes Park is known for high wind events. A garage door at an exposed site near Estes Park must use the actual site wind speed. That speed may be 150 mph or higher.

Building permits in unincorporated Larimer County. The building department uses this document to review structural calculations for permit applications. A design with the wrong snow load or wind speed will fail plan review.

After-the-fact inspections. Home buyers and inspectors checking an older structure need to know the design criteria in effect when it was built. The 2026 update supersedes earlier editions. Prior editions may have used different snow load conversion factors.

What this means for you

Fort Collins homeowners: on a typical in-town lot, use 115 mph Vult (Exposure B or C) and 48 psf design ground snow load as starting values. Confirm your exposure category before selecting a door wind rating.

Western Larimer County: do not assume 115 mph applies to mountain or foothill sites. Check the Larimer County document for your specific elevation and terrain. Exposed ridgetop sites may require a site-specific wind study.

Apply the 1.6 conversion. If you see a raw SEAC 2016 snow load value, multiply by 1.6 before using it in any current structural calculation. The Larimer County January 2026 document notes this requirement explicitly.

G Brothers serves Fort Collins, Loveland, and surrounding Larimer County communities and can confirm the applicable design criteria for your specific project location.

Full text and source

The Larimer County Structural Design Information document is at https://www.larimer.gov/sites/default/files/uploads/2022/structural_design_information.pdf.

Larimer County structural design criteria apply to unincorporated county areas and are referenced by municipalities in the county. Fort Collins and Loveland have their own adopted codes; confirm design requirements with the applicable city building department for projects within city limits.

Want to put numbers to this? Use the interactive roof snow load calculator below, or open the full roof snow load calculator with examples and notes.