Building Code Foundation Requirements

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If you're building any house, the first thing that will go to it is the foundation. A house can't stand without a good foundation. That's why you must choose the best foundation for your house before building it. But for you to start a building foundation, there is a building code for foundation requirements that you must follow. This article will discuss these requirements.

The Building Code for Foundation Requirement Basics

Building codes are established to ensure the safety, health, and welfare of people using buildings, whether public, industrial, or residential. These codes apply to the design, construction, and operation of buildings for them to meet acceptable levels of risk associated with life or property when an accident or other emergency occurs.

The Building Code for Foundation Requirement Basics
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There are several different building codes, depending on the kind of structure you are building. These include residential, commercial, industrial, public, and agricultural buildings. Building codes also depend on where you live in the world. Some structures will require only one type of code, while other structures may require more than one. Some of the common codes include;

International Building Code

One of the most common codes used was established in 2008. This code is known as the International Building Code, or IBC 2008. This building code has been recognized by many countries and state law entities throughout North America and Australia, leading to its widespread use around the world. IBC 2008 covers different areas that a building must meet to comply with the code.

The International Residential Code

The International Residential Code, IRC 2008, is another common code used commonly today. This code appears to guide the residential building, but it also covers the commercial part of the house too. It was created in 2006, but it was made into an official building code in 2008 by the International Code Council (ICC) due to popular demand. The IRC mandates how residential buildings are to be designed or built.

Building Foundation Site Requirements:

Building foundation site requirements typically include adequate and stable perimeters, frost line depth, and compaction. Here are some of them:

Site Grading

This requirement outlines the ground adjacent to where you tend to lay the foundation footings. The site grading is usually done on sloping ground. The exterior of the foundation must slope at a slope of 5 percent minimum. You need to ensure this continues for about 10 feet.

Foundation Perimeter Wall Requirements

The foundation perimeter wall must have an 18″ minimum width throughout the entire perimeter of the footing. The 18″ footing width can be filled with silty gravel or scrap, just as long as it is filled with some sort of material that will allow for drainage. If the foundation is to be poured on loose soil, you will need to install footings. Read more on buying top soil on our site.

Foundation Wall Thickness

The required thickness of the wall needs to be as consistent as possible for all areas where walls are present or within 2 feet of these exterior walls or footing perimeter. The minimum wall thickness should be 10 inches, and below-grade needs to be a minimum of 8 inches. 

What Makes a Good, Solid Building Foundation | Boots On the Roof
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Any foundation with two piers supporting the home must have at least two complete courses of the block. They should be between the top of the footing and the bottom of the footing to the lowest course of block used for unsupported height.

Foundation walls may not be more than 24″ above the ground. If the foundation wall is built of concrete block, it must extend at least 10 inches below grade rest on solid footing.

Load Bearing Values of the Soil

Another thing not to overlook is the capacity of the soil beneath the home. The standard is the same as building on solid rock foundations. The maximum allowable load bearing value for first and second-class soils (granular and sandy) and crushed stone footings is 12 tons per square inch; it is 15 tons per square foot for clayed sand, shale, or slate.

It's also a requirement to use undisturbed soil. Undisturbed soil means that the soil must not have been moved. For example, if you're building in a garden spot and want to put in a foundation, you must remove all topsoil and take it away from the area that will be filled with cement.

Apart from undisturbed soil, you need to carry out a soil test to know its Load Bearing Value (LBV) before you started digging. If you didn't do that, then it would be a good idea to get the services of a geotechnical engineer who can test the soil and see if there is a high probability that your foundation will hold up.

If the LBV is too low – meaning it may not support a building or other structure – then you have a couple of options:

  • Option 1 – Build up the soil. If possible, get people to dig below ground and add more dirt or other material to get the LBV high enough.
  • Option 2 – Get a geotechnical engineer to give you advice on what can be done to make it work. For example, adding pilings or pylons that go into the ground may be enough to support your foundation.
  • Option 3 – Put in larger foundations. This means you will have to redistribute the weight of the building over a wider area. This, however, can increase costs dramatically because more lumber is needed for beams and joists, which increase the size of the house.
  • Option 4 – Get the LBV re-measured to see if it can support the masonry foundations. If it cannot, then only an engineer's opinion of what is acceptable will help you decide how to proceed.

Concrete Floor Slabs

Be sure that you’ll be pouring concrete slab or a monolithic concrete pad on your home's floor. It's not a requirement to set your home on a concrete pad, but if you're building on an area with no solid bedrock and the soil can't safely support your home, it'll be required. Monolithic slabs are made of a single piece of poured concrete that covers the entire footprint of the house.

House Design Your Own House

When building your own house, you'll want to look into the building codes foundation requirements regulations in your area. Every municipality has its own set of regulations, so it's best to check with them before beginning construction.

Typically, houses are built with floors supported by beams, or concrete slabs that rest on concrete footings poured into the ground at least 6 inches deep.

FAQs Building Code Foundation Requirement

What happens if you don't adhere to the building foundation code?

If you don't follow the standards set in place by your local municipality's building codes, then your house may not pass inspection. If it fails inspection, you'll have to spend time and money making changes to bring it up to code before being able to move into the house.

How are footings for foundations poured?

Concrete footings are generally dug out with large machinery or constructed by hand. After the footing hole is dug, the soil inside of it is compacted to support load-bearing structures like beams and posts. A footing forms a solid base for concrete to be poured onto.

Bottom Line on Building Code Foundation Requirement

Without even these codes in place, you must do your own assessment of the home to make sure it's safe for you and your family. If you notice anything questionable, it's best to hire an inspector or appraiser to tell you more about any problems with the structure.

Always err on the side of caution when making such large financial decisions, whether it's buying a home or building your own house from scratch.


Kristina Perrin

Kristina Perrin

Kristina is an expert DIY home remodeler and mom to three. When she's not cooking or experimenting with new recipes, you can find her working on new home improvement projects or writing about her favorite kitchen appliances or DIY projects on Kitchen Infinity blog.

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