How Much Does a Home Addition Cost in Brevard County?

A home addition in Brevard County costs an estimated $200–$450 per square foot of new space for a ground-floor room, $275–$500 for a second story and $150–$300 to convert a garage, based on our Florida planning ranges. That puts a 400 sq. ft. ground-floor addition at roughly $80,000–$180,000 for construction, before design, engineering and permit fees. In Brevard, a septic system, a flood zone or an oceanfront lot can add cost and time on top of that.

This page covers what's specific to the Space Coast: the one Melbourne figure we found and why it's lower than ours, four worked budgets, and the local rules that change the price. For general advice on building up or out, see our Florida home addition cost guide.

Home addition cost per square foot

Home addition construction cost in Florida (per sq. ft. of new space)

Item	Estimated range	What affects it
Ground-floor addition	$200–$450per sq. ft.	Includes slab foundation, concrete block or frame walls, roof and finishes. Kitchens and bathrooms push costs up.
Second-story addition	$275–$500per sq. ft.	Structural reinforcement, stairs and temporary weather protection.
Garage conversion to living space	$150–$300per sq. ft.	Uses the existing slab and roof. Raising the floor, insulation and windows add cost.

These ranges cover building the new space: the foundation, walls, roof and finishes. They don't include architectural or engineering fees, the survey, permit fees, septic or sewer work, or furniture. We haven't found reliable, dated data showing whether Brevard prices run above or below the rest of Florida, so plan with the full range.

What moves an addition from the low end to the high end:

• Basic (low end). A simple rectangular room on a slab with no plumbing, such as a bedroom or family room. Walls match the house, windows and doors are standard products rated for your location, the roof extends simply from the existing one, and finishes are builder grade.
• Standard (middle). A bedroom suite with a bathroom, or a family room with a large sliding door. Mid-range flooring and tile, a new or larger air conditioning system, and a check of electrical panel capacity.
• Premium (high end). A kitchen or more than one bathroom, a complicated roof tie-in, a second story, custom impact windows and doors, high-end finishes or a raised foundation in a flood zone.

What a Melbourne cost guide says, and why it's lower

Local addition prices are hard to find. The only Melbourne-specific figure we found is on one national cost-guide website's Melbourne page, which shows no date. It puts home additions at about $121–$241 per square foot for standard to premium construction, and says luxury projects can cost up to about twice the upper figure.

At that rate, a 400 sq. ft. addition would cost about $48,500–$96,500 (400 × $121 and 400 × $241, rounded). At our ground-floor range it's $80,000–$180,000. The gap usually comes down to:

• What's counted. Per-square-foot figures often leave things out. One national renovation company's 2026 guide, for example, works through a 600 sq. ft. addition at $250 per sq. ft., about $150,000, and notes that soft costs, utility upgrades, site work and finish upgrades come on top. We couldn't confirm what the Melbourne figure includes.
• Room type and finish level. Bathrooms and kitchens cost far more per square foot than bedrooms, and "premium" on one site can mean mid-range on another.
• Date and source. An undated page may reflect older prices, and cost-guide websites and contractors publish these figures to attract leads or business. Our ranges come from several Florida contractors' published cost guides, most dated 2026, and are deliberately wide. None of these figures is a quote.

Treat the Melbourne figure as a sign that prices vary, not as a budget. If a quote comes in near it, check what's missing before you sign. See why contractor quotes differ and how we estimate costs.

What the per-square-foot price leaves out

Our statewide addition guide explains what drives construction cost. In Brevard, these items are the most likely to sit outside any per-square-foot figure, ours included:

• Survey, design and engineering. A current survey comes first, then permit drawings and structural engineering.
• Permit fees. In unincorporated Brevard, some residential permit fees scale with job value. The county's page for new one- and two-family homes, for example, lists a $25 application processing fee and a building code review fee of $75 for the first $1,000 of job value plus $3.25 for each additional $1,000. We didn't find the fee for addition permits, so ask the county for a current estimate. Cities set their own; Melbourne's fee schedule took effect August 7, 2026.
• Septic and flood-zone work. A septic review, upgrade or sewer connection, a higher floor for the new room, or, past the 50% line, bringing the whole house up to current flood rules (see below).
• The existing house. A roof tie-in can make it sensible to reroof the whole house at once (see roof replacement cost in Melbourne and Brevard), and more space may need a larger air conditioning system or a panel upgrade.
• Site and living costs. Moving a driveway or utilities, landscaping, and somewhere to live during a second-story job.

Four example budgets

These are illustrations, not quotes. Each estimate multiplies the square footage by the low and high end of our planning ranges and covers construction only, with no design, permit, septic or flood-zone costs. Real prices depend on your home, your lot and the plans.

Scenario 1: garage conversion to a bedroom

Assumptions: a two-car garage of about 400 sq. ft. becomes a bedroom and closet, with no bathroom, outside a flood zone. The existing slab, walls and roof stay.

• Estimated cost: 400 sq. ft. × $150 to 400 × $300 = $60,000–$120,000

The garage door opening has to be closed in, usually with a wall and a window or door rated for your home's wind design, and the floor may need raising to meet the house. In unincorporated Brevard, the county's Residential Addition permit covers converting non-living space to living space. If the house is on septic, the new bedroom will likely need health department review. Check zoning and HOA rules on garages and parking before you design.

Scenario 2: primary suite with a bathroom, home on septic

Assumptions: a 360 sq. ft. ground-floor bedroom, closet and bathroom on a slab on the mainland, outside a flood zone, with the roof tied into the existing house. The home has a conventional septic system.

• Estimated cost: 360 sq. ft. × $200 to 360 × $450 = $72,000–$162,000

The bathroom makes the upper half of that range more likely. Septic work isn't included: the system will be reviewed against the new bedroom count, and if it has to be upgraded in the Indian River Lagoon program area, the new system may have to be nitrogen-reducing. Get a septic quote before you commit to the plans.

Scenario 3: family room addition in a flood zone

Assumptions: a 500 sq. ft. family room with no bathroom, on a lot near the lagoon in a FEMA flood zone. For the 50% check, we assume a tax-assessed building value (not counting land) of $220,000.

• Estimated cost: 500 sq. ft. × $200 to 500 × $450 = $100,000–$225,000
• Estimated market value using the county's method: $220,000 plus 15–20% = $253,000–$264,000
• The 50% line: half of that, about $126,500–$132,000

Only the low end of the estimate stays under the line. If the building department treats the project as a substantial improvement, the whole house, not just the addition, generally has to meet current flood rules. Find this out before you finalize the design, not at permit review.

Scenario 4: second-story addition on the barrier island

Assumptions: an 800 sq. ft. second story over an existing one-story home in Satellite Beach or Indian Harbour Beach.

• Estimated cost: 800 sq. ft. × $275 to 800 × $500 = $220,000–$400,000

An engineer has to confirm that the existing walls and foundation can carry the new floor. The roof is open during part of the work, so plan around hurricane season (June 1 to November 30). If the home is in a flood zone, even the low estimate of $220,000 reaches the 50% line for any building with a market value of $440,000 or less. On an oceanfront lot seaward of the coastal construction control line, ask the Florida Department of Environmental Protection whether the work needs a state permit or an exemption determination as well as the city permit.

Need a contractor for this project?Request a home addition estimate

Brevard factors that change the budget

County or city permit

Brevard County Planning and Development issues building permits only in the unincorporated parts of the county, such as Viera and Merritt Island. Melbourne, Palm Bay, West Melbourne, Rockledge, Cocoa Beach, Satellite Beach, Indian Harbour Beach and other cities and towns run their own building departments. A mailing address doesn't settle it, so confirm which office covers yours; our Brevard County permit guide lists each one.

• Unincorporated Brevard. The county's Residential Addition permit covers exterior additions that change the footprint or add height, conversions of non-living space to living space, and accessory structures such as garages. County staff review each application, and owner-builders must apply in person.
• Melbourne takes applications through its online permitting system and asks for a survey for additions.
• Indian Harbour Beach publishes residential permit checklists, including one for additions.

On a contract over $5,000, you'll also need a recorded Notice of Commencement before the first inspection. Watch the calendar too: the Florida Building Commission's work plan sets the 9th Edition (2026) of the Florida Building Code to take effect December 31, 2026, and some building departments say applications submitted on or after that date must meet it. If your plans are being drawn now, ask which edition they're designed to.

Septic and the Indian River Lagoon

If your home is on septic, an addition brings in a second office: the Florida Department of Health in Brevard County, which handles septic permits. State rules require reapproval before work starts when a change increases sewage flow or alters the conditions the system was approved for. Adding a bedroom (including a converted garage or den) commonly triggers review, and so does building over or too close to the tank or drainfield, even for a room with no bathroom.

If the system can't handle the change, it may need repair or an upgrade. In the Indian River Lagoon Protection Program area, which covers parts of Brevard, new septic systems aren't allowed where central sewer is available, and where it isn't, they must be nitrogen-reducing. By July 1, 2030, many homes on conventional septic in that area must connect to sewer if it's available, or upgrade, so it can make sense to do that work with the addition rather than dig up new landscaping later.

• New systems in the north. A 2025 federal court order has affected permits for new septic systems in the northern lagoon watershed, roughly from the Melbourne Causeway north. If your project needs a new system there, ask the health department about its current status.
• Grants. Brevard County's Save Our Indian River Lagoon program offers upgrade grants of up to $20,000, depending on the parcel, with at least $6,000 for every property in its plan area since a December 2025 county decision. You must apply and receive a notice to proceed before work starts.

We don't have reliable installed prices for nitrogen-reducing systems in Brevard, so get a septic contractor's quote. Our septic and septic-to-sewer guide covers the rules in detail and DEP's map for checking your lot.

Flood zones and the 50% rule

If your home is in a FEMA flood zone, an addition counts toward the 50% rule: when the cost of an improvement equals or exceeds 50% of the building's market value before work starts, the whole building generally has to meet current flood requirements, which can mean elevating it. Brevard County's flood-zone guidance says market value may be estimated from the building's tax-assessed value (not land or accessory structures) plus about 15–20%, that an owner who disputes the figure may hire a state-licensed appraiser, and that a substantially improved building needs an elevation certificate from a licensed professional surveyor.

Run the numbers early, as in Scenario 3. In unincorporated Brevard, the county's Floodplain Administration keeps elevation certificates for buildings in special flood hazard areas going back about ten years, so ask whether yours is on file. Cities have their own floodplain staff and may calculate differently. Our guide to the FEMA 50% rule explains the rule in full.

Oceanfront lots and the coastal construction control line

Brevard's coastal construction control line (CCCL) runs along the Atlantic coast from Port Canaveral Inlet to Sebastian Inlet. Seaward of it, a room addition outside the existing footprint needs a Florida Department of Environmental Protection permit as well as the local building permit, and has to meet stricter siting and design rules. Only beachfront parcels seaward of the line are affected; DEP's Map Direct viewer shows the line for your address. See CCCL permits in Florida.

Wind design for new openings

Brevard County publishes building code wind speed maps that show the design wind speed for an address. That speed, and for some lots near open water the exposure, decides whether new windows and doors must be impact-resistant or protected by approved shutters. Either way they need product approval and a suitable design pressure rating, so ask your building department early; see impact window costs in Brevard.

Impact fees

Brevard County's impact fee FAQ says: "Additions, remodels, and/or alterations of an existing dwelling do not require payment of additional impact fees." That's the county's program. Cities may charge their own fees, and fee rules change, so confirm with the county's impact fee staff, or with your city if you live inside city limits. If the new space could work as a separate living unit, such as a guest suite with its own kitchen, ask how it will be classified.

Setbacks, easements and the HOA

Setbacks, lot coverage, height limits and easements decide how big an addition can be and where it goes, and on a septic lot the drainfield takes up room too. In a planned community, the HOA's architectural committee often has to approve the size, roofline and materials. Since July 1, 2026, Florida law (HB 803) bars an HOA from requiring a building permit before it reviews your application, so you can apply to both at once. Get HOA approval in writing before you sign a construction contract; see HOA approval in Florida.

Who should build it

Unless you're acting as an owner-builder, an addition needs a general, building or residential contractor. Brevard County says it has no handyman license and handymen may do only unregulated work. Check any contractor on MyFloridaLicense.com and on Brevard County's Licensed Contractor Search, where a contractor appears only with a current active license, general liability insurance, and workers' compensation insurance or an exemption. Our Melbourne contractor hiring guide covers the steps, and contractor deposits in Florida explains the rule that a contractor who takes more than 10% up front must apply for permits within 30 days. Before you sign, our renovation contract checklist covers the plans, allowances, payment schedule and notices the contract should include.

Common mistakes

• Comparing a per-square-foot figure with a quote without knowing what each includes. Ask contractors to price the same plans and list design, permits, site work and allowances separately.
• Designing before the basics are known. The survey, flood zone, assessed building value and septic location can each change the size, shape or price of the addition.
• Assuming a room without a bathroom skips septic review. A new bedroom, or any addition over or near the tank or drainfield, can trigger it.
• Splitting one project to stay under the 50% line. Closely related permits can be counted together, and an artificial split isn't allowed.
• Letting a contractor pull an owner-builder permit for work they're doing. That puts the legal responsibility on you. See owner-builder permits.

Next steps

1. Confirm your permitting office and order a survey.
2. Check your flood zone and building value. Ask whether an elevation certificate is on file and work out your 50% line.
3. If you're on septic, contact the health department early. Ask whether your plans need an evaluation or upgrade, whether sewer is available or planned, and what grant your parcel qualifies for, before signing anything.
4. Read your HOA rules and confirm impact fees with the county or your city.
5. Get plans, then written, line-item quotes from licensed contractors based on the same drawings, with a contingency for surprises. See renovation timelines for scheduling, and whole-house remodel costs in Melbourne if the addition is part of a bigger project.