Home additions in Houston
More space without moving: room additions, primary suites, second stories and garage conversions that blend into the house you already have.
Quick answer: Home additions in Houston usually cost $250–$450 per square foot, and most take 6–10 months from design to move-in, including permit review. Before design, we check your lot for floodplain status, deed restrictions and impervious-cover limits, because those decide what you can build.
What’s included
- Site check: floodplain, deed restrictions, setbacks and drainage
- Design, structural engineering and foundation plan
- Permit set with grading and impervious-cover worksheets
- Foundation, framing, roofing tie-in and exterior matching
- HVAC, plumbing and electrical extended by licensed trades
- Interior finishes and final inspections
Home additions projects we build
Room additions
A ground-floor addition needs a new foundation tied to the existing slab or pier-and-beam. Houston’s expansive clay soil means the foundation design matters as much as the floor plan.
Second-story additions
Adding up keeps your yard. An engineer confirms whether the existing foundation and walls can carry the load; often some reinforcement is needed.
Garage conversions
Converting a garage to living space needs insulation, a raised or leveled floor, conditioned air and permitted egress. Some deed restrictions require covered parking to remain.
Garage conversions: cost and detailsCasitas and in-law suites
A detached casita or attached suite with its own bath gives family or guests privacy. Utility connections and setbacks drive the budget.
Three things that decide what you can build
- Floodplain: in Houston’s mapped floodplains, additions above the substantial-improvement threshold must be elevated above the 500-year flood level.
- Deed restrictions: Houston has no zoning, so neighborhood deed restrictions set setbacks, height and sometimes materials.
- Impervious cover and drainage: the city asks how much new hard surface you add, using its impervious-cover worksheet.
Build out or build up?
| Option | Pros | Watch for |
|---|---|---|
| Ground-floor addition | No stairs, simpler structure | Uses yard; floodplain elevation |
| Second story | Keeps the yard; adds the most space | Engineering and roof removal |
| Garage conversion | Lowest cost per square foot | Parking rules, floor height |
Home additions cost in Houston
Typical ranges for full-service work in Greater Houston, reviewed every year.
| Project | What it usually includes | Typical Houston range |
|---|---|---|
| Room addition | Foundation, framing, roof tie-in, finishes | $250–$450 per sq ft |
| Primary suite addition | Bedroom, bath and closet | $150,000–$330,000 |
| Garage conversion | Insulation, floor, HVAC, finishes | $25,000–$60,000 |
Ranges are for full-service work in Greater Houston, including design, permits, licensed trades and cleanup. They are based on 2025–2026 Houston data from Remodeling’s Cost vs Value report, Angi and Block Renovation, plus our own pricing. Your written estimate is itemized for your home.
Permits
The City of Houston’s residential addition permit requires plans, a grading worksheet for excavation and fill, and a calculation of impervious cover, with plan review before approval. Additions in a floodplain also go through floodplain review. We prepare and submit the full set.
Questions about home additions
How much does a home addition cost in Houston?
It depends on size, foundation and finishes; see the cost table above for our current ranges. Bathrooms and kitchens in an addition raise the cost per square foot.
Do I need a permit for an addition in Houston?
Yes. The City of Houston requires a residential addition permit with plans, a grading worksheet and an impervious-cover calculation, plus floodplain review where it applies.
Can I add a second story to my one-story house?
Often, but an engineer must confirm the foundation and walls can carry the load. Some reinforcement is common. We include that assessment in design.
Will an addition be affected by the floodplain?
If your lot is in a mapped floodplain and the project is large enough to count as a substantial improvement, the city requires elevation above the 500-year flood level. We check this before design starts.
Can a garage conversion be permitted?
Yes, as long as it meets building code for living space and your deed restrictions allow it. Some restrictions require covered parking to remain.
Where we work
Related services
Garage conversions
Garage to bedroom, office, gym or in-law suite.
Learn moreWhole-home renovation
Gut remodels and older-home updates.
Learn morePatio covers
Attached gable, hip and insulated patio covers.
Learn moreHelpful guides
Do you need a permit to remodel in Houston?
Which Houston remodeling projects need a permit, what the City of Houston asks for, how long review takes, and which nearby cities issue their own permits.
Read the guideRemodeling in a Houston floodplain
How Houston’s floodplain rules affect remodels and additions: the 50% substantial-improvement rule, elevation above the 500-year flood level and what to check.
Read the guideGarage conversions in Houston: rules, permits and cost
Can you convert your garage in Houston? Deed restrictions, parking, floodplain elevation, code requirements for a legal bedroom, permits and 2026 costs explained.
Read the guideHow much does a home addition cost in Houston?
Home addition costs in Houston for 2026: price per square foot, primary suite additions, bathroom additions, second stories and garage conversions compared.
Read the guideWill remodeling raise your property taxes in Houston?
How remodels and additions affect Houston property taxes: the 10% homestead cap, new improvements, repairs, disaster rebuilds, over-65 freezes and protests.
Read the guideHow to finance a home remodel in Texas
Texas home equity loans and HELOCs have unique rules: the 80% limit, 12-day wait, 3-day rescission and $4,000 minimum draws. Ways to pay for a Houston remodel.
Read the guideHow to protect your home from contractor liens in Texas
Texas law requires a “Know Your Rights” disclosure, a subcontractor list and a 10% reserve for 30 days. How to avoid paying twice on a Houston remodel.
Read the guideHOA approval for remodeling in Texas
How HOA approval works in Houston-area neighborhoods, and what Texas law says HOAs can’t prohibit: solar panels, impact-resistant shingles and generators.
Read the guideHow long does a remodel take in Houston?
Realistic Houston remodeling timelines: design, HOA review, City of Houston permits and construction for kitchens, baths, patio covers, additions and conversions.
Read the guideReady to talk about your addition project?
Free in-home estimate with a written scope, price and schedule.
Or call (346) 456-5310