Permit briefing
Do you need a permit for a patio?
The model building code exempts sidewalks and driveways but never names patios, so the city decides; Austin treats an at-grade slab as exempt flatwork.
The reliable short answer
Decide the surface material, whether it stays at grade and whether anything will be built over it before assuming the work is exempt.
Planning complexity
Low
Local answer required
Yes
The model code’s answer
Does a patio need a permit?
The model code does not say. The International Residential Code's list of exempt work names sidewalks and driveways, not patios, so the answer comes from the city. Austin exempts concrete flatwork outside the public right-of-way, which covers a slab poured at grade; a roof over it, a raised surface or a connection to the house is not on either list.
| Rule | What it exempts |
|---|---|
| Model code (IRC R105.2) | Names sidewalks and driveways, not patios |
| Austin | Concrete flatwork outside the right-of-way |
| Los Angeles | No patio line; an awning to 4 ft from the wall is exempt |
Because the model list is silent, the city's own list decides, and it can ask for more than a building permit. On an Austin lot served by a septic system, adding a patio triggers an on-site sewage facility review by Austin Water. In Los Angeles the question most patios meet is the cover: fixed to the house, only a canopy or awning reaching no more than 4 feet from the wall is exempt, and LADBS values a bigger one per square foot when it sets the fee.
A three-step permit decision
1. Separate the slab from any cover
Austin lists residential concrete flatwork that is not in the public right-of-way among work exempt from a building permit; a cover is a separate question. The exempt lists of the model code, Austin, Houston and Los Angeles name no patio cover, so a freestanding one has to fit a small-building line: Austin's 200 sq ft and 15 feet outside flood hazard areas, Houston's 120 sq ft one-story accessory structure, and in Los Angeles the city decides whether one up to 120 sq ft counts with small sheds. Phoenix exempts a one-story, detached, non-cantilevered shade structure up to 200 sq ft, and San Diego a patio cover at a single dwelling unit in the RS and RX zones up to 300 sq ft of roof and 12 feet high, outside every required yard. Fixed to the house, a cover is exempt only as a small awning: up to 54 inches from the wall with no support but the wall under the model code and in Austin and Houston, and up to 4 feet in Los Angeles, outside Fire District No. 1.
2. Count the surface as impervious cover
Austin defines impervious cover as any human-made surface that does not absorb rainfall, naming walkways, impermeable driveways, rooftops, parking areas and some decks. A solid patio adds to that total, which is capped by zoning.
3. Read the exemption narrowly
The same Austin page states that work exempt from a permit must still comply with applicable building codes, city codes and all other applicable ordinances. Exempt from a permit is not exempt from the rules.
What Austin and Los Angeles say about a patio
Austin
- No permit
- Concrete flatwork that is not in the public right-of-way.
- Permit
- On a lot with a septic system, adding a patio needs an on-site sewage facility review by Austin Water. The exempt list names no patio cover; its nearest line is a window awning that reaches no more than 54 inches from the wall and needs no support but the wall.
- Fees
- Exempt flatwork needs no building permit, so it carries no permit fee.
Los Angeles
- Ask the city
- The code names no patio. The line a slab would have to fit covers platforms, walks and driveways no higher than 30 inches, with no basement or story beneath them, and LADBS decides whether it does. It also decides whether a freestanding roofed cover up to 120 square feet is one of the similar uses its line for small sheds takes in.
- Permit
- Fixed to the house, a cover is exempt only as a canopy or awning reaching no more than 4 feet from the wall, outside Fire District No. 1. A bigger one, or a freestanding roofed cover over 120 square feet, needs a permit, and LADBS values it per square foot when it sets the fee.
- Valuation
- Patio cover, per square foot$16
- Patio enclosure, per square foot$22
What to have ready before you call
- Finished surface height relative to adjacent grade recorded
- Any cover, roof or attachment to the house declared
- New patio area added to the existing impervious cover total
- Setback, easement and drainage path confirmed before pouring
- Permeable options priced where the impervious total is tight