Mobile Home Foundation Requirements Listed By General Area

by Mar 4, 2019Blog, Buying a mobile home, Moving A Mobile Home, Safety

You’ve weighed your setup options for your new mobile home. And you’ve decided that a permanent foundation is the way to go. That’s why you’re wondering about mobile home foundation requirements. Are there any differences between areas of the United States when it comes to your mobile home foundation?

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Foundation footers

First, let’s talk a moment about footers. Think about this — the foundation bears the weight of the house. But what bears the weight of the foundation? That’s part of the job of the footer, which is a support structure (usually something like reinforced concrete) that goes underneath the foundation.

Because they’re wider than the foundation, footers can spread the load over a larger area of soil, helping avoid sinking or settling of the foundation. How much wider they are than the footer is something that can vary by location. For instance, in a place with certain kinds of soil, the footer may end up being even twice as wide as the foundation.

The frost line

Next up, let’s take some time to look at the frost line. And no, that’s not the title of an engrossing book, even though it may sound like it. It’s actually a term that applies to mobile home foundation requirements (and foundations in other homes, too). In fact, it may be helpful to phrase the concept we’re dealing with like this: how deep do you have to dig?

When you put a mobile home on a foundation, of course, you have to follow building codes for your area. And one code that varies based on where you’re located is how deep you have to set your footers.

When soil freezes then defrosts, it can shift. Thus, the houses set on top of this soil could also shift. Obviously, you don’t want your house shifting. Instead, you want it good and stable. Frost line requirements help prevent problems by telling you how deep you must dig to be out of the danger zone.

Frost lines vary

The tricky thing about the frost line is that it’s not always the same even within one state. For example, in one area of the state of Utah, it could be 20 inches, and in another area 40, according to Archadeck of Salt Lake.

A line dug deep in soil

Thus, when you build your mobile home’s foundation, it’s important that you know how deep you’re required to dig in your area. If you’re feeling curious about how the frost line varies across the US, read on.

The South

There’s plenty to love about the South. Including (as any snowbird will tell you) the warmer weather. And that warmer weather translates to not having to dig as deep for your foundation as in northern states.

According to the map on which measures “extreme frost penetration (in inches) based upon state averages” you could be looking at something like 5-10 inches when it comes to frost penetration.

frost depth map of US

Courtesy of

This could include parts of states like Texas, Alabama, Mississippi, Louisiana, Georgia, South Carolina, and North Carolina, and Florida.  To determine how deep you’re required to place your footers, check your particular locality within any of these states.

The Northeast

Wondering how deep frost can go in states in the Northeastern United States? Judging again by the map, it can be above 40 inches (including a lot above 40 inches) in states like New York, New Hampshire, Vermont, Massachusetts, and Maine.

The Midwest

Looking again at the map, you can see that the Midwest has a pretty sizable range when it comes to frost line. Case in point, consider Minnesota and Missouri. According to the Star Tribune, “The Minnesota State Building Code requires footings to be a minimum of 42” deep in the southern part of the state, and a minimum of 60” deep in the northern part of the state.” Meanwhile, in Missouri, the frost line could be as low as less than 20 inches in one area.

The far West

Then take Western California. Out there, the map informs you’re going to have a much milder frost line—a low number like in the South.  

North, South, East, West— home is best

While you may be interested in the frost lines of other areas of the US, one frost line affects you directly. That is, it affects your own mobile home foundation requirements. And that’s the frost line of your own location.

Check mobile home foundation requirements in your area

Do your due diligence to determine what the requirements related to frost line are where you’re planning to place your mobile home. There can be different requirements depending on where you are in a state. So check, don’t assume. While you may be able to find the information online, you can also try calling your local government officials to check with them.

More to get you ready for your mobile home

Once you’re aware of the mobile home foundation requirements in your area, check out our article on What You Need To Know About Putting A Double Wide On A Basement. And if you’re trying to pick out your mobile home, check out our Mobile Home Buying Tip: How To Find And Buy Your Dream Mobile Home.

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