Short answer: in Tampa, Angi puts a bedroom and bath addition at an average of $104,230, with most projects between $37,838 and $118,053, or about $160 per square foot (range $80 to $220) (updated June 18, 2026). Adding a bathroom alone in Tampa averages $35,315 (Angi, August 2026). A Florida room (sunroom) averages about $35,000 nationally, and Angi lists $35,900 for Florida (September 2026).
These are typical ranges, not quotes. In Pinellas County, the biggest surprises with additions aren't the lumber: they're the flood-zone rules, the engineering and what's under the ground.
How much does a room addition cost per square foot?
Angi's Tampa figures for a bedroom and bath addition run $80 to $220 per square foot, about $160 on average (June 2026). A bathroom addition costs more per foot because of plumbing and tile: Angi's Tampa page lists $475 to $725 per square foot to add a bathroom, versus $250 to $340 per square foot to convert existing space into one (August 2026). Florida rooms run about $75 to $250 per square foot (Angi, national, September 2026).
How much does it cost to add a bedroom and bathroom?
Angi's Tampa figures by size (updated June 18, 2026):
| Addition size | Typical cost (Tampa) | Do it yourself? |
|---|---|---|
| 250 sq ft | $20,000–$55,000 | No: structural work, sealed plans and permits |
| 300 sq ft | $24,000–$66,000 | No |
| 400 sq ft | $32,000–$89,000 | No |
| 460 sq ft | $37,000–$102,000 | No |
| 560 sq ft | $45,000–$124,000 | No |
| 600 sq ft | $48,500–$133,000 | No |
The same page lists permits at about $500 to $3,000 or more, general contractor overhead and fees at 10% to 20% of construction costs, and demolition and site prep at about $1.30 to $2 per square foot.
How much does it cost to add a bathroom?
Angi puts adding a bathroom in Tampa at $5,045 to $75,675, with an average of $35,315 (August 2026). By type: a half bath runs about $5,500 to $15,000, a full bath $13,000 to $58,000, and a primary bath $28,000 to $105,000. Plumbing and electrical work on an addition is done by licensed plumbing and electrical contractors (s. 489.113(3), Fla. Stat.). Our bathroom remodel cost guide covers remodeling an existing bathroom.
How much does a Florida room addition cost?
Angi's national Florida room guide (updated September 29, 2026) puts the average at $35,000, from about $5,000 for a simple three-season room to about $70,000, and lists $35,900 as the Florida average:
| Florida room size | Typical cost (national) | Do it yourself? |
|---|---|---|
| 8 x 10 ft | About $12,000 | No: permit and plans |
| 10 x 12 ft | About $18,000 | No |
| 12 x 16 ft | About $28,800 | No |
| 12 x 20 ft | About $36,000 | No |
| 16 x 20 ft | About $48,000 | No |
| 20 x 20 ft | About $60,000 | No |
The same guide lists a prefab three-season room at about $10,000 to $20,000 and a custom one at $10,000 to $50,000.
Cost to enclose a porch or convert a screen room
Angi's national porch enclosure guide puts enclosing a porch at $8,701 to $28,366, averaging $17,820, and lists a three-season room at $7,000 to $55,000 and a year-round sunroom at $16,000 to $70,000 (national, updated October 2026). Turning a screen room into heated and cooled living space usually means new walls, windows or doors, insulation and a permit, so it prices closer to an addition than a screen repair.
Home addition cost in Florida vs. national
For comparison, Angi's national home addition guide puts the average addition at $50,991, with a normal range of $21,886 to $83,367 and $80 to $200 per square foot for building out (national, updated October 2026). Treat these as rough guides: bedroom and bath additions with plumbing usually land higher.
What drives the price
- Size and plumbing. A bathroom or kitchen in the addition costs far more per square foot than a bedroom.
- Foundation and soil. A new slab or footings tie into the existing house; poor soil or a high water table adds engineering.
- Flood zone. In a flood zone, the addition can trigger the substantial improvement rule (below), which can change the design or the budget.
- Roof tie-in. Matching the existing roof line and tying in the new roof is done by a licensed roofing contractor.
- Windows and doors. Impact-rated windows and doors cost more; see our impact windows cost guide.
- Design and engineering. Pinellas County says structural work requires plans signed and sealed by an architect or engineer.
Permits for a room addition in Pinellas County
A room addition needs a building permit: the Florida Building Code requires a permit to construct, enlarge or alter a building (FBC-Building 105.1). Pinellas County lists "Room additions, garages, enclosed porches, and interior remodels" and "Pools and spas, decks, sheds, carports and screen rooms" among common residential permit types, says "All structural work requires building plans digitally signed and sealed by an architect or engineer," and says to confirm zoning and setback requirements first (Pinellas County). The state's under-$7,500 permit exemption doesn't apply to structural work or properties in a flood zone (Pinellas County; s. 553.79(1)(g)). Inside a city, your city's building department issues the permit; see our Pinellas permit guide and building permit cost guide.
On a job this size, Florida law also requires a recorded Notice of Commencement before work starts on most jobs over $2,500 (ss. 713.13, 713.02(5)), and the permit office must get a copy before the first inspection when the contract is over $5,000 (s. 713.135).
Additions in a flood zone: the 49% and 50% rules
Additions count as improvements under the flood rules, and each jurisdiction sets its own threshold:
- St. Petersburg (49%): the city's review package defines substantial improvement as "any reconstruction, rehabilitation, addition, or other improvement of a structure, the cost of which equals or exceeds 49% of the market value of the structure," and requires the package when the construction value is 25% or more of the structure's market value (City of St. Petersburg, PDF).
- Unincorporated Pinellas County (49%): the county says "all improvements are subject to the 49% structure value rule," and that even work you do yourself counts toward it (Pinellas County).
- Clearwater (50%): improvements costing 50% or more of the structure's market value trigger flood-protection requirements (City of Clearwater, PDF).
Other cities set their own; check yours before you design. Our house-raising cost guide covers what happens when the rule is triggered.
Room additions in Clearwater, St. Pete and Pinellas County
As a Florida Certified General Contractor, we build permitted additions and screen-room conversions across Pinellas County, coordinating the engineer, the permit and licensed trade partners for electrical, plumbing, A/C and roofing. See our renovations and permitted work service, or ask for a free estimate.
Frequently asked questions
How much does it cost to add a room in Florida?
In Tampa, Angi puts a bedroom and bath addition at an average of $104,230, or about $160 per square foot (range $80 to $220), as of June 2026. Size, plumbing, the foundation and flood-zone rules move the price most.
How much does a room addition cost per square foot?
About $80 to $220 per square foot for a bedroom and bath addition in Tampa (Angi, June 2026). A bathroom addition runs $475 to $725 per square foot in Tampa, and a Florida room about $75 to $250 per square foot nationally.
How much does it cost to add a Florida room?
Angi's national average is $35,000, with Florida at $35,900 (September 2026). A simple three-season room can start near $5,000, and a large, high-end room can reach about $70,000.
Do I need a permit for a room addition in Pinellas County?
Yes. Pinellas County lists room additions, enclosed porches and screen rooms as permit types and says structural work needs plans signed and sealed by an architect or engineer. The under-$7,500 exemption doesn't cover structural work or flood zones. Inside a city, confirm with that city's building department.
Does an addition count toward the 49% or 50% flood rule?
Yes, in a flood zone. St. Petersburg's 49% definition of substantial improvement includes additions, unincorporated Pinellas County applies 49% to all improvements, and Clearwater uses 50%. Check your city's own threshold.
Sources
- Angi: Cost to add a bedroom and bath in Tampa, FL (updated June 18, 2026)
- Angi: Cost to add a bathroom in Tampa, FL (updated Aug. 3, 2026)
- Angi: Florida room addition cost (national, updated Sep. 29, 2026)
- Angi: Cost to enclose a porch (national, updated Oct. 30, 2026)
- Angi: Home addition cost (national, updated Oct. 28, 2026)
- Pinellas County: Residential permits
- Pinellas County: Permit exemptions for work under $7,500
- Pinellas County: Substantial damage and substantial improvement
- City of St. Petersburg: Floodplain substantial improvement/substantial damage review package (PDF)
- City of Clearwater: Non-substantial damage/improvement information (PDF)
- Florida Statutes s. 489.113: subcontracting licensed trades
- Florida Statutes s. 553.79: permits, including the under-$7,500 exemption
- Florida Statutes s. 713.13: Notice of Commencement
- Florida Statutes s. 713.02: exemption for improvements of $2,500 or less
- Florida Statutes s. 713.135: Notice of Commencement and permits
These ranges come from the published sources listed above (Tampa Bay, Florida or national, as marked). They aren't PHRS prices or quotes. Every home is different, so we price each job after seeing it. Ask for a free estimate.
General information, not legal, insurance or engineering advice. Rules change and vary by city; confirm with your building department, DBPR, your insurer, an attorney or an engineer as fits.