What is the Frost Line Depth in Utah, and Why is this so Important?

When you think about deck safety, all sorts of images come to mind, but do you think about the deck’s post holes and footings, how deep they go, and whether the ground around them will freeze? It’s okay if you don’t because we think about that for you. It’s our job to know the required depth of a deck’s footings based on your exact location within the state and your property’s elevation. If your deck contractor gets this wrong, your deck may incur structural damage as the soil around the deck footings freezes and thaws, contracts and expands.

Frost line depth in Utah

Technically the concrete footings for your deck must extend deeper than the frost line, which is the greatest depth at which moisture in the soil will freeze. The deeper you dig, the less likely the soil there will freeze; below the frost line, the soil will not freeze. It would be simpler if the frost line depth was the same for the entire state, but that’s not the case. The frost line depth in Utah varies from 20" in the southwestern portion of the state to 40" in the state’s northeastern corner.

To comply with local requirements, you need to know the specific frost line depth for your location. For example, the city of North Salt Lake details the code for building within the city, but if you don’t live within this jurisdiction, your builder is governed by a different set of criteria. We will always make sure your deck or other outdoor living project meets your local requirements.

Frost line depth in the Salt Lake area

In the Salt Lake area, the frost line depth is 30". We take this measurement very seriously, and so does the local building department. The same office that issues building permits also requires that a building inspector come out to measure the holes we dig for your deck footings before we pour concrete. With Archadeck of Salt Lake as your deck designer and builder, you won’t have to worry about the technical requirements. We handle all permitting and coordinate with the building department for the required inspections.

Why do footings need to be below the frost line?

There’s a lot you don’t see going on below the ground’s surface, including seasonal changes as the moisture in the soil freezes and thaws repeatedly. If your deck’s concrete footings are not deeper than the frost line, this shifting soil can actually heave when it thaws, pushing the deck’s footings and posts upward. As the footings and posts rise, the entire deck can buckle and experience structural damage. That’s why deck designers and builders — and local building inspectors — pay so much attention to the frost line depth.

We are well versed in local design criteria and always meet and often exceed the local building codes. The hassle of permits, inspections, and building codes is one of the best reasons to hire a deck builder like us. Let us focus on frost line depth requirements, while you prepare to enjoy your new backyard. Call today for a design consultation. 801.683.2355

Learn more about all the requirements for building a safe deck in Utah.

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