Quick answer
The City of Austin’s Development Services Department reviews residential permits under the 2024 International Residential and Building Codes with local amendments, effective July 10, 2025. New homes, additions and extra units usually need engineered foundations because of Central Texas expansive clay, and structural work beyond the code tables needs a Texas-licensed engineer’s seal.
Austin is one of the most active residential markets in the country, with new homes, additions and extra units on existing lots. Knowing what the city expects keeps your project out of the comment-and-resubmit loop.
Which codes apply
Since July 10, 2025, Austin enforces the 2024 editions of the International Residential Code, International Building Code, Energy Conservation Code and Existing Building Code, along with the Uniform Mechanical and Plumbing Codes, all with local amendments. Projects outside city limits follow the county or the nearby city’s rules instead.
Why foundations need engineering here
Much of the Austin area sits on expansive clay that swells when wet and shrinks when dry. Foundations that ignore it crack and move. Engineered foundations, often post-tensioned slabs or slabs with deepened beams, are designed for the soil conditions, usually based on a geotechnical report.
Extra units on one lot
Austin’s HOME code changes allow more homes on many single-family lots than before. Each new unit needs its own permit review, and site planning, utility capacity, fire separation between units and foundation design are common review points. See our ADU engineering guide.
Projects that usually need an engineer
- New homes, additions and extra units with new foundations
- Removing bearing walls and open-plan remodels
- Foundation repair for settled or heaving slabs
- Retaining walls on Hill Country slopes
- Pools near structures or slopes
Licensing
Sealed engineering for Texas projects must come from an engineer licensed in Texas. Most Austin submittals are made online as digitally sealed PDFs.
Cost and turnaround
Fixed fees: review and stamp from $249, engineered plans from $599, multi-discipline packages from $1,999. See our Texas engineering page and pricing.
What to send us
- Property address
- Survey, floor plans or a sketch
- Geotechnical report, if you have one
- Any comments from Development Services
Common questions
Do I need a soils report in Austin?
For new foundations it is strongly recommended and often expected, because foundation design depends on how much the clay can move.
Which code does Austin use?
The 2024 International Residential and Building Codes with local amendments, effective July 10, 2025.
Can I add a second home on my Austin lot?
Often yes under Austin’s HOME rules, subject to zoning, lot size and utility capacity. Each unit needs a permit.
Does my engineer need a Texas license?
Yes. Sealed drawings for Texas projects must come from a Texas-licensed engineer.