Pre-Submission Review · Free

Addition Plan Check

Austin, TX

Additions are where setback and height violations happen most often. Your existing house was built compliant — but adding square footage changes the math on lot coverage, FAR, and setbacks. What was legal before may not be legal after the addition. A second-story addition, for example, can trigger increased side setback requirements in many cities.

  • Calculate combined lot coverage (existing footprint + proposed addition)
  • Check FAR impact — second stories don't change coverage but affect FAR significantly
  • Verify increased side setback requirements for two-story construction
  • Confirm parking isn't displaced by the addition footprint

Project Location

Building Dimensions

Setbacks

Coverage & Parking

Additional Notes

Home Addition in Austin: What You Need to Know

Additions are where setback and lot coverage violations happen most often. Your existing house was compliant when built — but adding square footage changes the math on lot coverage, FAR, setbacks, and parking. What was legal before may not be legal after an addition.

Critical checks for additions in Austin:

  • Lot coverage impact — Your addition's footprint adds to the existing building footprint. If the combined coverage exceeds Austin's limit (typically 40–50%), the addition will be denied without a variance.
  • FAR recalculation — A second-story addition doesn't change lot coverage but significantly impacts FAR. Calculate total floor area (existing + proposed) against your zone's FAR limit before designing.
  • Side setback increases for two-story — Many cities require additional side setbacks for two-story construction. A ground-floor addition may be fine at 5' from the property line, but a second story might need 7–8'.
  • Parking displacement — If your addition eliminates existing parking (like building over a driveway pad), you may need to provide replacement spaces elsewhere on the lot.
  • Existing nonconformities — If the original house already violates current setbacks or height limits (legal nonconforming), an addition cannot extend the nonconformity. The new portion must fully comply with current codes.

Enter your combined dimensions (existing + proposed) in the form above. We'll check the total project against Austin's current codes so you know where you stand before hiring an architect.

How Plan Check Works in Austin

01

Enter your project details

Fill in the form above with your lot size, setbacks, building height, and other dimensions — the same numbers on your architectural plans.

02

We check against Austin codes

Your project is compared against Austin's specific zoning requirements — setbacks, height limits, lot coverage, parking ratios, and FAR limits for your zone.

03

Get a prioritized report

Critical violations, warnings, and advisory items — ranked by what a Austin plan checker will flag first. Fix issues before you submit and save weeks of correction cycles.

Austin Zone Requirements

Zone Front Side Rear Height Coverage
SF-2 — Single Family Standard 25' 5' 10' 35' 40%
SF-3 — Family Residence 25' 5' 10' 35' 40%
SF-4A — Small Lot 15' 3' 10' 35' 45%

Frequently Asked Questions

What setbacks does Austin require for home addition projects? +

Austin requires a 25' front setback, 5' side setback, and 10' rear setback in the most common residential zone. Specific requirements vary by zone — enter your zone code above for exact numbers.

How long does Austin plan review take? +

Initial plan review in Austin typically takes 4-8 weeks. If corrections are required, each resubmission adds another 2-4 weeks. Running a pre-check before submitting can eliminate the most common correction items and save one or more review cycles.

What is the maximum building height in Austin? +

The most common residential zone in Austin allows a maximum height of 35 feet. Height measurement methods vary — some cities measure to the highest ridge, others to the midpoint of the roof. Check the specific zone requirements for your property.

Is this plan check tool free? +

Yes. Create a free account to run unlimited plan checks against Austin's building codes. The tool checks setbacks, height limits, lot coverage, parking requirements, and flags common issues that Austin plan reviewers look for.

What are the most common addition plan check corrections in Austin? +

The most frequently flagged items in Austin include: Progressive ADU rules (2023 reform); No ADU parking required; Impervious cover limits. Our tool checks for all of these automatically.