Awaiting expert review. This page covers safety or regulatory rules that change over time. A qualified reviewer has not yet checked it; the sources below are dated so you can verify each point.
Quick answer
Foundation design and building codes are the legal rules that set how a foundation must be designed and built, usually drawn from a model code such as the International Residential Code (IRC) and then adopted, and often amended, by a state or local government.
The model code supplies the text. The jurisdiction decides which edition and which changes apply, so the rule for one house may differ from the rule for a house in the next county.
Quick facts
The key facts about Foundation Design and Building Codes, with sources:
- Model code for houses
- International Residential Code (IRC), published by the International Code Council 13
- Concrete materials
- IRC R402.2 and ACI 318 govern concrete used in foundations 5
- Expansive soil
- IRC R403.1.8 sends designers to IBC 1808.6; R401.4 covers soil tests (2015 IRC as cited) 4
- Load path
- IRC R301.1 says building as prescribed gives a complete load path to the foundation 3
- Review status
- Held pending review; no licensed engineer or code official has signed this page
Key takeaways
- Foundation rules come from a model code, most often the IRC for houses, adopted by a state or local government 1.
- Adoption varies. States and cities adopt different editions, adopt only parts and add amendments 21.
- The code covers more than footing size: soil tests, concrete, drainage, expansive soil and the load path all appear in it 453.
- Where the code is silent or does not apply, an engineer’s design governs. The building department decides what applies to your address.
- This page is held pending review. It names the sources and editions behind each statement, and it is not legal or engineering advice.
- Always confirm with your local building department. Do not rely on a section number from a web page for a permit or a repair.
What foundation design and building codes are
A building code is a set of minimum rules for how a structure must be built so it is safe.
For a one- or two-family house in the United States, the common model is the International Residential Code, or IRC, published by the International Code Council (ICC).
FEMA says the I-Codes include the IRC for one- and two-family dwellings, and that they have been widely adopted and used by local communities, in whole or in part with amendments 1.
For foundations, the IRC has a chapter on foundations and sections on footings, foundation walls, drainage and under-floor space. A model code is not law until a jurisdiction adopts it. That is why the same foundation detail can be required in one town and handled differently in another.
This page explains how the system works. It does not give a design. For the parts themselves, see foundation footing and reinforced concrete foundation.
General information, not a diagnosis of your house
General information, not a diagnosis of your house. This page is held for review. No licensed engineer or code official has signed it. Section numbers appear only where a loaded source quoted them, with the edition that source used.
How a code reaches your foundation
The path has four steps. First, a model code is written, such as the IRC. Second, a state or local government adopts it by law.
FEMA says States or communities adopt the model codes, and that State and local governments often amend or adopt only portions of them, so how strict a local code is can vary widely 1.
Third, the local building department applies the adopted version when it reviews plans and inspects work. Fourth, the designer or builder follows the plans that passed review.
AWC’s adoption page makes the same point for the whole country. In some fashion every state has adopted one or more of the ICC codes, but the number of codes, the method of enactment and their application varies considerably across the 50 states 2.
AWC also warns that its map may not reflect the most current information 2.
Where the code allows an engineered design, the engineer’s calculations take over. Texas’ bulletin on foundation concrete gives an example: foundation designs must supply the material specifications, including minimum compressive strength, and the builder follows the engineer’s specifications when ordering concrete 5. See concrete compressive strength.
- Model codeICC publishes an edition of the IRC
- AdoptionA state or local government adopts it, often with amendments
- Plan reviewThe building department checks plans against the adopted code
- DesignPrescriptive tables or an engineer’s design set the details
- InspectionThe building official or an approved agency checks the work
What the foundation code addresses
| Topic | What the code touches | Source and edition quoted |
|---|---|---|
| Concrete materials | Minimum specified strength by location and weathering; air entrainment for weathered concrete | IRC R402.2 (TDLR cites IBC Ch. 19, IRC 402.2, ACI 318); California’s 2025 residential code shows a table 56 |
| Soil tests | Tests where soils are likely to be expansive, compressible, shifting or unknown | IRC R401.4 as cited by Texas for the 2015 IRC 4 |
| Expansive soil | Soils meeting four listed conditions are treated as expansive; design follows IBC 1808.6 | IRC R403.1.8 and R403.1.8.1, 2015 IRC 4 |
| Load path | Building as prescribed provides a complete load path to the foundation | IRC R301.1 3 |
| Fastening and bracing | Fastening schedule and braced wall lines by wind speed | IRC Section R602.10 as cited by PNNL; no edition stated 3 |
| Flood | Flood-resistant construction is part of the IRC | FEMA, I-Codes include flood-resistant requirements 1 |
| Inspection | Building officials may accept inspection reports from approved agencies or individuals | IRC R104.4, 2003 edition, as quoted by Mesquite, Texas 7 |
Example: how one expansive-soil rule is built
A Texas Department of Licensing and Regulation bulletin (2015 IRC and 2015 IBC) walks through the expansive-soil rule. It is a good example of how the code points from one section to another. It is a quoted example, not a design for any site.
| Step | What the bulletin says | Why it matters |
|---|---|---|
| 1 | IRC R403.1.8 requires foundations on expansive soils to be designed per IBC Section 1808.6 4 | The residential code hands off to the building code |
| 2 | IRC R403.1.8.1 treats soils as expansive if they meet four provisions, based on plasticity index, particle size and expansion index 4 | The code defines “expansive” by test results, not by appearance |
| 3 | IRC R401.4 allows soil tests where soils are likely expansive, compressible or shifting 4 | A soil investigation may be required before design |
| 4 | R401.4.2 lists alternatives to a full geotechnical evaluation, such as removing the soils or stabilizing them 4 | The code allows more than one route |
Section numbers are as that bulletin cites them for the 2015 edition. Later editions and local amendments may renumber or change them. See expansive clay soil and soil plasticity index.
Where the code shows up in practice
You meet the code at the permit counter, on the approved plans and at inspections. A new foundation, an addition and many repairs go through plan review. Permit paperwork often names the code edition in force.
The code also shows up in contracts and quotes. A scope of work for a repair should say which plans and code the work follows. Some cities ask for engineer-sealed designs.
The City of Mesquite, Texas, wrote in a 2006 policy letter that all foundation repairs there require a permit and an engineer’s sealed design, and that the city finals the permit once it receives the engineer’s letter approving the repairs 7.
That is one city’s rule, and it is dated. Your city may do it differently.
Flood zones add rules. FEMA says the local building official or floodplain manager may add to the scope of work for substantial improvements in flood hazard areas 1. See foundation repair scope of work for how that appears in a contract.
What the code gives you
What codes do well
What codes do not do
- Are minimums. FEMA notes local codes can be more or less stringent than the model code 1.
- Do not guarantee a house will not move. Soil, water and workmanship still matter.
- Do not apply the same way everywhere, because editions and amendments differ 21.
- Do not replace an engineer’s judgment about a specific site.
Limits of what a code tells you
A code states minimum requirements for new construction. It does not say how to repair an existing foundation, which method suits a house or how long a repair will last. Repairs follow engineered plans and local permit rules.
A code also cannot see your soil. FEMA’s manual says most local building codes specify an allowable bearing capacity to use in design if soil properties have not been specifically determined, and that the actual allowable bearing capacity should be determined by a soils engineer 1.
Table values are a starting point for sizing, not a finding about your lot. See soil bearing capacity.
And web pages, including this one, can lag. Editions change and amendments are issued. A section number that was right in the 2015 edition may not match your jurisdiction’s edition today.
Code compliance is not the same as no movement
A foundation can meet the code at the time it was built and still move later because of soil, water or loads. Code is a minimum standard for design, not a warranty.
How codes affect cost
We do not print prices. Codes affect cost through the design that is required, such as soil testing, engineering, reinforcement, drainage details, inspections and permit fees. Stricter local amendments can add work. A site in a flood zone or on expansive soil may need more design and review than a simple lot.
When you compare quotes, ask whether each one includes engineering, permits and inspections. Read our cost guide for how quotes are built. Use the cost calculator to test scope assumptions, and ask each bidder to name the code edition they price to.
How to find the rules for your foundation work
A practical outline for an owner. Rules differ by place.
- Find the right office: Contact your city or county building department. FEMA advises contacting the local building official or floodplain administrator early 1.
- Ask which code and edition apply: Ask for the adopted edition and any local amendments, because adoption varies 21.
- Ask whether your job needs a permit and an engineer: Some cities require engineer-sealed plans for foundation repairs 7.
- Ask what is inspected and by whom: Inspections may be done by the city or by approved agencies 7.
- Get it in writing: Ask that the contract name the plans, code and permit.
- Keep records: Save the permit, plans, inspection reports and final sign-off with the house records.
Keeping your code records in order
Paperwork is the maintenance side of code compliance.
- Keep the permit, approved plans and inspection sign-offs for the foundation and any repairs.
- Keep the engineer’s letter or sealed report for any repair. Mesquite’s policy letter treats it as the basis for finaling a permit 7.
- Keep cylinder break reports or concrete tickets if you have them.
- Note the code edition on the permit so you know which rules applied.
- Ask your building department whether permits for past foundation work were closed.
Risks and when to call a structural engineer
The main risks around codes are working without a permit, relying on the wrong edition and assuming a contractor’s plan meets the local rules.
Mesquite’s letter says anyone working without the required permit is asked to stop work until a proper permit is obtained at a double fee, and may face a citation 7. Rules like that vary by city.
The code does not diagnose movement. Cracks, sloping floors and sticking doors are clues. Movement history, displacement, water, construction details and soil change what they mean.
Call a licensed structural engineer if movement is significant, widening or changing; if walls bow or are displaced; if doors and windows stick along with new cracks; if corners separate; or if you have any safety doubt. Our engineer guide explains who to call, and your building department can say what permits apply.
Do not start structural work without checking permits
Foundation repair often needs a permit and engineered plans. Digging beside a foundation or jacking a house without them can cause damage and can break local rules.
Model code, edition and adoption
Model code: the International Residential Code (IRC) for one- and two-family dwellings, with the International Building Code (IBC) used for engineered work.
The editions named in our loaded sources are the 2003 IRC (quoted by Mesquite for R104.4) and the 2015 IRC and IBC (Texas TDLR bulletins) 74.
PNNL cites IRC R301.1 and R602.10 without naming an edition 3.
We could not load ICC’s own code pages for this review, so the section numbers here are as the cited sources gave them.
Standards the code points to: ACI 318 for structural concrete, with ASTM test methods, appears in the Texas concrete bulletin and in California’s R402.2 56. ASCE 7 is the loads standard FEMA refers to for dead, live, snow, wind and seismic loads 1.
Adoption: varies. Some jurisdictions adopt the IRC statewide, some at the local level, and some amend it 21. Where no code is adopted, FEMA encourages designers and builders to follow a model code 1.
Authority: The local building official decides what applies at your address. The code book is not a substitute for that answer.
Held for review
This page is held pending review by a licensed structural or geotechnical engineer or a code authority. No reviewer has signed it. Treat every section number as a pointer to check, not as a requirement for your house.
Code, standard and permit compared
| Term | What it is | Who controls it |
|---|---|---|
| Model code | Published text such as the IRC 1 | A code body such as ICC |
| Adopted code | The model code as a state or city made it law, with amendments 1 | The state or local government |
| Reference standard | A document the code points to, such as ACI 318 or ASCE 7 51 | The standards organization |
| Permit | Official permission to do the work, after plan review | The local building department |
| Engineered design | A design by a licensed engineer for the specific site | The engineer of record, reviewed by the building official |
Building code myths
- Myth The IRC is the law everywhere.
- Reality It is a model. States and local governments adopt it in whole or in part, often with changes 12.
- Myth If it passed inspection, it cannot move.
- Reality Code sets minimum design rules. Soil, water and loads still act on the house over time.
- Myth Every repair needs the same permit.
- Reality Rules differ by city and by type of repair. Ask your building department.
- Myth A web page can tell me which section applies.
- Reality Editions renumber and amendments differ. Only the building department can say what applies at your address.
- Myth A contractor’s plan is the same as an engineer’s design.
- Reality Some cities require engineer-sealed plans for foundation repairs 7. A contractor’s sketch may not meet that.
Regional factors in foundation codes
Regions push codes in different directions. Texas treats expansive soils through IRC R403.1.8 and IBC 1808.6 in the 2015 editions it cites 4.
California publishes its own residential code with its own R402.2 concrete table 6. In hurricane-prone coastal regions, PNNL says a licensed structural engineer must determine load path connections 3.
In flood hazard areas, FEMA says the IRC includes flood-resistant requirements and local officials may add scope 1. Ask your building department which of these apply where you live.
What to do with this
Call your building department before a build, an addition or a structural repair. Ask for the adopted code edition, whether a permit and engineer are required and what inspections apply.
Then ask each contractor to price to those answers. The buyer checklist lists what to ask for when you are buying a house, and how we vet explains how we handle credentials.
- If Planning a new foundation or addition
- Then Ask the building department for the adopted code, amendments and plan-review needs
- If Getting repair quotes
- Then Ask each bidder which code, permit and engineer’s design the price assumes
- If Buying a house with past foundation work
- Then Ask for permits, plans and inspection sign-offs
- If Movement that is widening or changing
- Then Call a licensed structural engineer; do not wait on paperwork
Questions about Foundation Design and Building Codes
What building code governs foundations for houses?
For one- and two-family houses, the usual model is the International Residential Code (IRC), with the International Building Code used for engineered work. FEMA says the I-Codes are widely adopted by communities, in whole or in part with amendments 1. Your building department can tell you which edition and amendments apply.
Which IRC edition applies to my house?
It depends on your state or city. AWC says the number of codes, the method of enactment and their application vary considerably across the states 2. Our sources cite the 2003 and 2015 editions, and one names no edition. Ask your building department for the adopted edition.
Does the code say how big a footing must be?
The IRC has prescriptive footing tables, but the right size also depends on soil and loads. FEMA says allowable bearing capacity should be determined by a soils engineer and that table values are for preliminary sizing 1. Your plans and local code give the figure for your house.
What does the code say about expansive soil?
In the 2015 IRC as cited by Texas, section R403.1.8 requires foundations on expansive soils to be designed per IBC Section 1808.6, and R403.1.8.1 sets conditions for treating a soil as expansive 4. Later editions and local amendments may differ.
Do foundation repairs need a permit?
Often, but it varies. The City of Mesquite, Texas, said in 2006 that all foundation repair work there requires a permit, with an engineer-sealed design 7. Other places differ. Ask your building department before work starts.
Who inspects foundation work?
The local building official, or an approved agency the official accepts. Mesquite’s letter cites 2003 IRC R104.4, which lets the building official accept reports of inspections by approved agencies or individuals, and says the city finals the permit once the engineer’s letter approving the repairs arrives 7. Practice varies by place.
Is a foundation that meets code safe from movement?
Not necessarily. The code sets minimum design rules for new work. Soil, water and loads can still move a foundation that met the code when built. If movement is significant, widening or changing, call a licensed structural engineer.
What if my town has not adopted a building code?
FEMA notes that some communities have not adopted a building code, and encourages designers and builders there to follow the requirements of a model building code 1. Rules for repairs, utilities and flood zones may still apply. Check with the county and state.
Why is this page held for review?
Because it explains regulatory rules where a wrong section number or edition could mislead. It is written from loaded sources with their editions, but no licensed engineer or code authority has signed it. Check every number with your building department.
Sources
- FEMA P-259, Engineering Principles and Practices for Retrofitting Flood-Prone Residential Structures, 3rd ed. (Jan. 2012), retrieved .
- American Wood Council, Adoption of ICC codes by state, retrieved .
- PNNL Building America Solution Center, Continuous Load Path Provided by Connections from Roof through Wall to Foundation, retrieved .
- Texas Department of Licensing and Regulation, IHB Technical Bulletin TB 10-01, Foundations on Expansive Soils – Residential (2015 IRC, 2015 IBC; rev. Oct. 16, 2018), retrieved .
- Texas Department of Licensing and Regulation, IHB Technical Bulletin TB 10-03, Concrete Acceptance for Foundations (Apr. 28, 2010), retrieved .
- 2025 California Residential Code, Section R402.2 Concrete (Title 24, Part 2.5), as reproduced by GoCodeBook; third-party copy, verify against the official publication, retrieved .
- City of Mesquite, Texas, Building Inspection Division, letter to foundation repair contractors on inspection policy (July 5, 2006; revised Nov. 22, 2006), retrieved .
Expert review
Written by the HyreFoundation Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Facts were checked against the FEMA, PNNL, AWC, Texas TDLR, City of Mesquite and California code documents listed above, retrieved 2026-10-14.
Code references are as those sources cite them for the editions they name. ICC code pages could not be loaded.
Review is pending: no licensed structural or geotechnical engineer or code official has reviewed this page.
Suggest a correction. We fix errors and say what changed.