Home Addition Cost in Palm Beach, Florida (From $120/sqft)

Cost Breakdown by Construction Phase

Rather than relying on a single headline number, it’s more useful to understand where addition costs come from:

1) Structural & Exterior Envelope

For a typical ground-level addition on slab:

Sitework and excavation: $5–$10 per sq ft

• Clearing, grading, mobilization, basic temporary protection

• Higher if access is tight or utilities need relocation

Foundation and slab (including footings): $15–$25 per sq ft

• Engineered footings, rebar schedules, termite treatment, thicker edge beams

• Built to current Florida Building Code requirements

Framing (walls, beams, roof framing): $18–$30 per sq ft

• Exterior walls, LVLs or steel where openings get wide

• Roof framing and tie-in details to the existing home

Roof sheathing, underlayment, basic roofing: $10–$18 per sq ft (of addition floor area)

• In coastal work, upgraded underlayments and fastening schedules can push this upward

Exterior envelope (WRB, stucco/siding, trim): $12–$20 per sq ft

Impact-rated windows and exterior doors (averaged): $10–$20 per sq ft (spread across the addition)

• Individual impact windows often land around $800–$1,400 per opening, with pricing also commonly discussed as $50–$75 per sq ft of glass

• Impact sliders and French doors often sit in the $2,000–$4,500+ range

👉 Structural + envelope subtotal: roughly $70–$100 per sq ft

MEP Rough-Ins (no fixtures or trim)

If the addition is a conditioned space (not a screened porch) you are paying for code-compliant systems.

Rough electrical: $8–$14 per sq ft

• Panel tie-ins, circuits, boxes, code-required AFCI/GFCI

Rough plumbing (if there’s a bath or wet bar): $10–$20 per sq ft (averaged)

• Roughly $1,500–$4,000 per bathroom rough is common as a conceptual anchor

HVAC rough-in and ducting (plus system upsizing share): $8–$15 per sq ft

• Ductwork, returns, supplies, potentially a new zone

👉 MEP rough-in subtotal: roughly $26–$49 per sq ft

Interior Shell (pre-finish)

Even without “finishes,” you still need a basic interior envelope.

• Insulation: $3–$5 per sq ft

• Drywall (hang, tape, texture, prime): $8–$14 per sq ft

• Basic interior doors and rough trim blocking: $4–$7 per sq ft

• Subfloor/slab prep for future flooring: $2–$4 per sq ft

👉 Interior shell subtotal: roughly $17–$30 per sq ft

Soft Costs and GC Margin (allocated)

This is the part people forget when they’re mentally doing per-square-foot math. Even a “simple” addition usually carries:

• Permits, impact fees, inspections: often $5–$12 per sq ft when spread across the new space

• Architectural and engineering: often $5–$10 per sq ft amortized on modest additions

• GC overhead and profit: commonly 15–25% of direct costs, which can translate to $15–$30+ per sq ft in blended pricing

👉 Allocated soft costs + margin: roughly $25–$40 per sq ft

Putting It Together

• Structural + envelope: $70–$100

• MEP rough-ins: $26–$49

• Interior shell: $17–$30

• Soft costs + margin: $25–$40

That lands you at a blended $120–$180 per sq ft before finishes range for a ground-floor addition in Palm Beach conditions.

Home Addition Cost by Type

The same square footage can price wildly differently depending on how much existing structure you need to reinforce, how you tie into the roof, and whether your footprint triggers more engineering.

Ground-Floor Additions (most straightforward)

Typical range (before finishes): $120–$180 per sq ft

These additions usually have the cleanest cost logic:

• New slab foundation

• Straightforward framing

• Direct tie-ins to existing utilities

Where costs jump toward the upper end:

• Flood-zone or elevated slab requirements

• Complex roof tie-ins or matching rooflines

• Lots of glass (more on that below)

Second-Story Additions (the premium category)

Typical range (before finishes): $200–$350+ per sq ft

Second-story additions cost more because you are paying for what’s invisible:

• Reinforcing the existing foundation and structure

• Heavier engineering for wind loads

• New stairs (a fixed cost that does not scale gently)

A practical anchor here: stairs alone often run $15,000–$30,000 as a fixed number, which is why smaller second-story additions can feel expensive. If you can build a second-story addition over an existing garage, you can sometimes save meaningful cost versus spanning the entire home, but the engineering still matters.

Garage Conversions (the budget entry point)

Typical range (before finishes): $90–$160 per sq ft

Garage conversions can be cost-effective because you’re not building the shell from scratch. You already have:

• A slab

• Exterior walls

• A roof

You are paying to make it habitable:

• Replace garage door with impact-rated openings

• Add insulation, drywall, and finishes

• Extend HVAC and electrical

One “watch this” item: An added bathroom can add $12,000–$25,000+ depending on plumbing complexity.

The Luxury Finish Layer

If you take one thing from this guide, let it be this: finish selections play a defining role in home addition budgets. They are where projects move from structural investment to fully realized living spaces, and where costs can scale quickly based on design intent.

Here are the finish categories that have the greatest impact on overall project cost:

Flooring Upgrades (Installed)

• Engineered hardwood: $14–$26 per sq ft

• Luxury vinyl plank/tile: $7–$18 per sq ft

• Large-format porcelain tile: $12–$25 per sq ft

• Natural stone (marble/travertine): $20–$45+ per sq ft

In this climate, engineered hardwood and porcelain are often selected for their balance of appearance, durability, and moisture performance. 

Natural stone is also widely used in Palm Beach additions, valued for its visual depth and long-term appeal, with care considerations that should be planned for as part of the overall finish strategy.

Ceiling Details (Installed Premium Add)

• Tray ceilings: $10–$25 per sq ft

• Coffered ceilings: $25–$45+ per sq ft

• Exposed beams: $20–$40 per sq ft

These details benefit from early coordination. Coffers and tray ceilings are most successful when they are planned into the framing from the outset, allowing proportions, lighting, and structure to align cleanly with the design intent.

Wall Finishes (Installed)

• Venetian plaster: $15–$30+ per sq ft

• Limewash / Roman clay: $8–$20 per sq ft

• Microcement / specialty finishes: $12–$35+ per sq ft

These finishes are often associated with “quiet luxury,” offering depth, texture, and a hand-applied quality that brings subtle richness to Palm Beach interiors.

Large Openings & Glass Walls

This is one of the most common luxury moves in Palm Beach: big sliding walls, floor-to-ceiling impact glass, and indoor-outdoor flow.

It also has real structural consequences.

Large openings can add $10,000–$50,000+ depending on span, system choice, and engineering requirements. Floor-to-ceiling windows and multi-panel sliders can run roughly $90–$180 per sq ft of opening for HVHZ impact-rated systems.

You are not only paying for the glass, but for:

• Reinforced headers (LVL or steel)

• More engineering

• Tighter tolerances and install coordination

Luxury Kitchens in Home Additions

If your addition includes a kitchen expansion or a new kitchen space (guest house, pool house, main home rework), kitchens can swing budgets faster than almost any other interior zone.

A few anchors from Palm Beach projects:

• Custom cabinetry: commonly $500–$1,500+ per linear foot installed

• Ultra luxury cabinetry: $1,500–$2,500+ per linear foot

• Quartzite countertops: $90–$150+ per sq ft installed

• Marble countertops: $70–$250 per sq ft installed

• Porcelain slab countertops: $60–$120 per sq ft installed

Luxury Bathrooms in Home Additions

Bathrooms are smaller spaces, but they’re dense (plumbing, waterproofing, tile labor, glass, ventilation, fixtures).

Common luxury features that push budgets:

• Steam showers: $15,000–$35,000

• Freestanding tubs: $8,000–$25,000

• Radiant heated floors: $10–$20 per sq ft

• Premium fixtures: $1,500–$5,000 (and higher)

In Palm Beach additions, a primary bath can easily land $50,000–$100,000+ once you go spa-level with stone, custom vanities, and smart shower systems.

Comfort & Smart-Home Upgrades

A new addition is the easiest time to get infrastructure right because walls are open and coordination is already happening.

HVAC Upgrades

• Standard HVAC rough-in + unit: $8–$15 per sq ft

• Premium HVAC with zoning/dehumidification: $15–$30 per sq ft

In our climate, dehumidification is a core comfort consideration. Proper moisture control is what allows new spaces to feel consistently comfortable, finished, and well-balanced year-round.

Smart Home Features

A basic smart package in an addition can sit around $5,000–$10,000 for common items like thermostats, security, and lighting control, with bigger systems scaling higher.

Lighting Design

• Basic recessed lighting: $3–$8 per sq ft

• Layered lighting: $8–$15 per sq ft

• Architectural lighting (coves, tracks): $15–$30 per sq ft

Lighting has a significant influence on how an addition ultimately feels. Thoughtful layering and fixture selection shape the atmosphere, scale, and overall sense of quality in the finished space.

How to Budget a Home Addition the Smart Way

A good addition budget is not one number. It’s a structure:

1. Structure + rough-in (the unavoidable build cost)

2. Finish allowances (the decision-heavy layer)

3. Soft costs and contingency (the protection layer)

If you separate those early, you gain control. 

If you blend them together and hope it works out, you end up making finish decisions mid-construction under time pressure. That’s when budgets drift.

Palm Club Perspective: Additions That Actually Get Built

Palm Club is not a general contractor. We don’t build.

We’re the team you start with to make sure you get the right one, and that your design is truly buildable before construction pricing begins.

That means:

• Build-ready design that accounts for structure, systems, and local constraints

• Scope and budget alignment before bids go out

• Transparent proposals from vetted general contractors

• Procurement support through Palm Club Logistics, so selections and lead times do not derail the plan

• Owner’s rep oversight to protect the design and keep execution honest through punch list