Building Codes And Design Loads

We take the time to understand not only your needs, but the region and other unique facotrs that go into creating your custom steel building. 

Why we ask for your Zip Code

We use this data for two reasons: 1) This allows us to accurately determine the distance between your location and our nearest shipping point. 2) We use this data to estimate the building code and design loads for your area. This is only an estimate. It is your responsibility to contract your local building official to determine the exact loading for your area. Some zip codes cover a wide area so the design loads may very within a zip code.

Building Code

Building codes are intended to provide for the safe use of buildings and structures under “normal” conditions. The code describes exactly how each part of the building should be loaded and designed. These loads are based on Snow load, Wind Speed, Seismic Coefficient (earthquake), Collateral load and Exposure. These loads will be applied in various “Design Combination” to determine the most critical loading. From these combinations all member sizes and spacing will be determined.

Snow Load

In the northern US, design of a building to withstand snow loading is critical. Snow loading is dependent on several factors. These factors include roof slope, if the structure is heated, if the structure is insulated, if the roof slope is slippery or if it contains high friction that will “hold” the snow on the roof. Our pricing system takes the most conservative of these factors into consideration when designing your building.

Wind Speed

As wind blows it places pressure on the building. The exact pressure is based not only on the formulas and tables contained in the specific building code chosen, but also the size and shape of your new building. By entering the Wind Speed, our pricing systems will give the optimum member sizes and their spacing.

Seismic Coefficient

This is the influence of earthquake activity on your steel building. The higher this number the more influence seismic has or the greater the seismic loading. Some building codes such as the Uniform Building Code (UBC) or the California Building Code (CBC) also use seismic zone. These also influence seismic design; Zone 0 having the least influence and Zone 4 having the greatest.

Collateral Load

The collateral load is the loading on the building caused by additional construction materials such as a false ceiling, sprinkler system, lighting, Heating/Air-conditioning duct, etc. The following table is recommended loadings for each type of collateral load.


The characteristics of ground surface irregularities (natural topography and vegetation as well as constructed features) for the site at which the building is to be constructed.

Exposure A – Large city centers with at least 50% of the buildings having a height in excess of 70 feet.
Exposure B – Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger.
Exposure C – Open terrain with scattered obstructions.
Exposure D – Flat, unobstructed areas exposed to wind flowing over open water (excluding shorelines in hurricane prone regions) for a distance of at least 1 mile.

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