Home Addition Cost - Design, Permits and Build Under One Contract

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How Much Does a Home Addition Cost in Boca Raton?

A home addition in Boca Raton, FL typically costs between $45,000 and $130,000, with most projects landing in the $65,000-$95,000 range depending on square footage, structural complexity, and finish level. Single-story room additions on the lower end of that scale average around $150-$220 per square foot, while two-story additions or projects requiring significant foundation work push toward $250-$320 per square foot in the current Boca Raton market. Most homeowners in established neighborhoods like Broken Sound, Boca Pointe, or Woodfield Country Club can expect the full project timeline to run 10-18 weeks once permits are pulled from the City of Boca Raton Building Division.

Home Addition Cost Breakdown (2026)

The table below reflects what Rowan Construction Group is quoting on active Boca Raton projects in 2026. These are written scope-based estimates, not ballpark figures – every line item below corresponds to a category that gets its own signed written price before any work starts, per Clause 1 of the Haven Standard.

A few things push that total meaningfully in one direction or the other. Adding a bathroom inside the new space – a walk-in shower installation runs $4,500-$12,000 in Boca Raton, a full bathroom remodel can reach $28,000 – changes the budget significantly because it pulls in plumbing rough-in, a separate inspection, and waterproofing requirements. Similarly, any addition that requires the roofline to be restructured rather than simply extended adds cost because the existing tile or shingle field has to be opened, matched, and resealed. GAF and Owens Corning materials hold up well in South Florida’s combination of UV intensity and hurricane-season wind loads, and those are what we spec. If the existing panel is at capacity – common in Boca Raton homes built in the 1980s and early 1990s in communities like Sandalfoot Cove – a subpanel or full panel upgrade lands in the estimate before anyone pulls a permit, so the number the customer signs is the real number.

What Affects Home Addition Pricing in Boca Raton

The Boca Raton market has its own cost drivers that don’t apply the same way in Miami or Fort Lauderdale. Below are the factors that move the final number on nearly every project we price here.

• Florida Building Code and wind-load requirements: Palm Beach County sits in a High-Velocity Hurricane Zone for structural purposes, and every addition must meet the current Florida Building Code’s wind-resistance specs. That means engineered framing plans, impact-rated glazing (impact window installation in Boca Raton runs $8,000-$25,000 depending on count and size), and inspected tie-downs at the foundation. These aren’t optional upgrades – they’re line items in the permit set, and skipping them fails the inspection.
• HOA design review and setback requirements: A significant share of Boca Raton’s housing stock sits inside HOA communities – Boca Grove, Broken Sound, Stonebridge – where architectural review adds 3-6 weeks to the pre-construction phase and sometimes mandates specific exterior finishes, roof tile profiles, or paint palettes. We pull the CC&Rs and submit the design package before the permit application goes to the city, so approvals don’t stack.
• Existing slab condition and soil bearing: South Florida’s high water table and sandy substrate mean a slab extension needs a geotechnical check in some parts of Boca Raton, particularly in older sections near the Intracoastal or in low-lying areas west of Military Trail. If the existing slab has settled or cracked, that gets documented in the photo record before foundation work starts – and the correction is in the written price, not a change order surprise.
• Square footage and ceiling height: A 400-square-foot addition with standard 9-foot ceilings costs measurably less than the same footprint with 10-foot ceilings and coffered details. Volume drives material quantity on drywall, insulation (spray foam is common here for energy performance), and HVAC sizing. We spec the ceiling height and finish details in the written scope so neither side guesses.
• Finish selections and fixture brands: A primary suite addition with Kohler plumbing fixtures, Cambria quartz surfaces, and KraftMaid cabinetry in a sitting area costs more than one with builder-grade selections – probably $12,000-$20,000 more on a typical scope. Those selections are named in the quote, not described generically as “allowance,” because an allowance is how a written price becomes inaccurate.
• Tie-in complexity with the existing structure: Matching a 1978 CBS (concrete block and stucco) home in Boca Del Mar to a seamless addition requires more labor than tying into a 2005 frame home in Boca Falls. The stucco profile has to be matched, the block courses have to align, and the roofline transition gets engineered rather than improvised. We photograph the existing conditions before the quote is written, so the complexity is priced in from the beginning.

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Boca Raton Permit Process for Home Additions

The City of Boca Raton Building Division requires a full building permit for any addition that increases the conditioned footprint of a home. That permit package typically includes architectural drawings stamped by a Florida-licensed architect or engineer, a site plan showing the setback dimensions, energy calculations under the Florida Energy Efficiency Code, and a truss or framing engineering package if the roofline is being extended.

Permit fees in Boca Raton run roughly $1,800-$5,500 for a residential addition, depending on valuation and scope. Plan review takes 3-5 weeks for standard residential projects; projects inside HOA communities that require concurrent architectural review often run 6-9 weeks from submittal to permit in-hand. We manage the permit application, respond to reviewer comments, and schedule all inspections as part of the project – the homeowner doesn’t need to track a permit portal or call the building department.

Inspections are staged: foundation before pour, framing before drywall, rough electrical, rough mechanical, and final. Each inspection gets documented in the photo record we deliver at project close – that documentation matters when the homeowner eventually sells, because a buyer’s inspector will ask for it.

Room Addition vs. Second Story vs. ADU: Which Is Right for Your Boca Raton Home?

These are structurally different projects and the cost gap is real, so it’s worth separating them before a number gets attached.

First-Floor Room Addition

The most common scope we quote in Boca Raton: extending the footprint on the rear or side of a single-story home. Cost range is $45,000-$130,000 depending on size and finish. These projects are generally the most permit-straightforward, the least disruptive to daily living, and the easiest to tie into existing HVAC and electrical systems. Rear additions in neighborhoods like Boca Raton Square and Camino Gardens work well here because lot depth typically allows the expansion without hitting setback limits.

Second-Story Addition

Adding a full second floor to a single-story home requires a structural engineer to evaluate whether the existing foundation and wall framing can carry the load – in many CBS homes built before 1990, the answer is “yes, with reinforcement,” which adds cost. The finished cost in Boca Raton typically lands at $90,000-$130,000 or more because the scope includes temporary weatherproofing of the existing structure, roof removal and rebuild, a new staircase, and the full Florida Building Code wind-load engineering package. The tradeoff is significant added square footage without using any additional lot area.

ADU Construction

An accessory dwelling unit – a self-contained living space with its own kitchen, bathroom, and entrance – runs $90,000-$220,000 in Boca Raton. The upper end of that range reflects detached ADUs built to full building code with separate utility meters, impact-rated construction, and finished interiors comparable to a small apartment. Palm Beach County’s ADU regulations allow these on single-family lots that meet minimum size requirements, and they’re increasingly common in Boca Raton’s 55-plus adjacent communities where families want a private space for parents or adult children. Our Home Addition in Boca Raton service page has more detail on ADU eligibility by zoning district.

Garage Conversion

Converting an existing garage to conditioned living space runs $30,000-$80,000 depending on whether the garage door opening gets walled in, how much of the slab is usable, and whether a bathroom is added. This is often the most cost-efficient path to added square footage in Boca Raton because the foundation, roof, and exterior walls already exist – the work is mostly interior rough-in, insulation, HVAC, and finishes.

How to Save on a Home Addition in Boca Raton

These are practical levers, not gimmicks. Each one reflects a real decision point on the projects we price in Boca Raton.

• Fix the scope before you sign anything. Scope changes after a project starts are the single biggest driver of final costs exceeding initial estimates across the industry. Under the Haven Standard, no change proceeds without a signed change order – which means the change is priced and agreed before the crew adjusts course. But the most effective protection is deciding on the layout, ceiling height, and finish level before the written price is issued, so there’s nothing to change.
• Match the roofline where possible. Adding square footage that tucks under the existing roofline – a rear bump-out that extends below the current eave, for example – avoids the full roofline rebuild cost. When the scope allows it, we’ll show both options in the written estimate so the cost difference is visible.
• Separate the addition from the interior remodel. Some homeowners want to renovate the connected interior spaces – the adjacent kitchen or hallway bathroom – at the same time as the addition. That can be economical because the crew and permits are already staged. But it’s a separate line item in the written scope, not bundled, so you can see exactly what each phase costs and sequence them if budget requires it.
• Use the Free Second Opinion offer. If you have a written estimate from another contractor, Rowan will review it line by line at no charge. Specifically, we’ll note where scope is vague (an “allowance” for windows without a brand or size is a number that will change), where structural or permit costs look light, and where the number is genuinely competitive. Call (754) 254-8065 to schedule that review – it takes about 45 minutes and you leave with a written comparison, not a verbal opinion.
• Don’t shrink the foundation to save money short-term. A smaller slab poured now that gets extended later costs more total than pouring the correct footprint once. The cost of breaking into a cured slab, re-forming, and repouring typically exceeds what the initial extra square footage would have cost. We’ll note this in the estimate if the scope looks like it might be undersized for the space the homeowner actually wants.
• Ask about material lead times before finalizing the schedule. Some finish materials – specific tile profiles, custom Wellborn cabinet configurations, certain Belgard paver patterns for exterior transitions – have 6-12 week lead times that can extend the project if they’re ordered late. Naming the materials in the written scope before the contract is signed means we can check availability and flag lead-time issues at the estimate stage rather than mid-project.

What Rowan Construction Group Delivers on Every Boca Raton Addition

Grant Rowan founded Rowan Construction Group in 2007 with one operational rule: the price is written before anyone picks up a tool, and it doesn’t change unless the customer signs a change order. Across more than 4,000 projects since then, that discipline has kept final costs within a few percent of the agreed number on the jobs we’ve built. The written price isn’t a soft estimate with asterisks – it’s a flat price with a written scope and a written warranty attached.

Every home addition project in Boca Raton includes the following as standard deliverables, not upgrades:

• A written flat-price quote with itemized scope before any work starts
• Signed change orders for any scope adjustment – no verbal approvals, no after-the-fact billing
• A documented photo record at each project phase, delivered to the homeowner
• Background-checked, uniformed crew members on every visit
• Permit application, plan review responses, and all inspection scheduling managed by Rowan
• The 365-Day Done Right Promise: if it’s not right within a year of completion, Rowan makes it right – that’s backed by the Haven Standard, in writing
• A live person answering calls 24/7 at (754) 254-8065

We source from more than fifty vetted material brands – GAF and Owens Corning for roofing tie-ins, Kohler and Toto for fixture packages, KraftMaid and Wellborn for cabinetry in addition kitchenette or sitting-room builds, Cambria and Caesarstone for countertop surfaces – because named materials produce accurate quotes. A quote that says “tile, approximately” is a quote that changes.

If you’re earlier in the process and want to understand the full scope of what a home addition involves before pricing, our home page outlines all seven trades we work across in Boca Raton.

FAQs: Home Addition Cost in Boca Raton, FL

How much does a home addition cost in Boca Raton?

A home addition in Boca Raton costs between $45,000 and $130,000 for most projects, with the midpoint around $75,000-$90,000 for a 350-450 square foot addition with mid-grade finishes. Smaller additions (under 250 square feet) sometimes come in below $55,000; additions that include a bathroom, a kitchenette, or a second-story structural component regularly exceed $100,000. Call (754) 254-8065 for a written estimate with a specific number for your scope – there’s no charge for the estimate.

How long does a home addition take to complete in Boca Raton?

Most single-story room additions in Boca Raton take 10-18 weeks from permit approval to final inspection. The pre-construction phase – drawings, HOA review if applicable, and City of Boca Raton permit review – typically runs 5-9 weeks on its own, so the total elapsed time from signed contract to a finished addition is usually 4-6 months. Projects in HOA communities with mandatory architectural review, like Broken Sound or Boca Grove, often run toward the longer end because the two review processes (HOA and city) don’t always run concurrently.

Do I need a permit for a home addition in Boca Raton?

Yes. Any addition that adds conditioned square footage to a Boca Raton home requires a building permit from the City of Boca Raton Building Division, along with stamped architectural drawings, a site plan, energy compliance calculations, and structural engineering if the roofline is being modified. Skipping the permit doesn’t save money – it creates a disclosed defect that surfaces in every future title search and buyer’s inspection. Rowan manages the full permit process as a standard part of every addition project.

Is it cheaper to add on to a house or buy a bigger one in Boca Raton?

In Boca Raton’s current market, adding on is almost always cheaper on a per-square-foot basis than buying. The median sale price per square foot in Boca Raton in 2025 ran well above $300 in most zip codes, and significantly higher in communities like Royal Palm Yacht and Country Club or Boca Raton Resort neighborhoods. A 400-square-foot addition at $200-$250 per square foot delivers space at $80,000-$100,000 total – the same square footage in a home purchase comes with transaction costs, a new mortgage rate, and moving expenses on top of the market price. That arithmetic is part of why we’re pricing more large additions in Boca Raton now than at any point since 2007.

Can Rowan give me a firm price before work starts?

Yes, and that’s non-negotiable. Under Clause 1 of the Haven Standard, a written price with a written scope is delivered before any work begins – on every project, every time. The quote is a flat price, not a range with allowances that expand later. If anything changes after signing, a written change order with a price and your signature precedes any change to the work. That’s how we’ve kept 4,000-plus projects within a few percent of the agreed number. Call (754) 254-8065 to get your written estimate started – Grant Rowan’s team turns around most addition estimates within 5-7 business days of the initial site visit.

What’s included in Rowan’s home addition estimate?

The written estimate includes every trade required to deliver a finished, permitted addition: demolition and debris removal, foundation work, framing, roofline tie-in, rough electrical, rough plumbing if applicable, HVAC extension or new system, insulation, drywall, interior finishes, exterior stucco or siding to match the existing home, impact windows and doors, and cleanup. Permit fees are listed as a separate line item so you can see them clearly rather than having them buried in overhead. The estimate also names the specific material brands for major components – roofing material, window brand, cabinet line if applicable – so there’s no ambiguity when the crew shows up.

Written by Grant Rowan, Owner at Rowan Construction Group, serving Boca Raton since 2007.

Pricing reflects the Boca Raton market as of 2026. Rowan Construction Group Boca Raton offers free estimates – call (754) 254-8065.