How Much Does a New Detached ADU Cost in Lantana, FL?
A new detached ADU in Lantana typically runs $90,000-$220,000 and takes 4-7 months from permit approval to final inspection. Most builds we see in Lantana’s 33462 ZIP fall in the 400-800 square foot range, with flood-zone compliance and impact-rated openings adding cost that inland Palm Beach County projects don’t face. Call (844) 665-0162 and we’ll walk your lot, pull the FEMA map, and give you a written estimate with real numbers.
How We Build a New Detached ADU in Lantana - Start to Finish
We’ve built enough ADUs in Lantana to know where the surprises hide. Here’s how we sequence a typical project, and what you’ll need to decide at each stage.
Stage 1: Site evaluation and feasibility (1-2 weeks)
We walk your property, measure setbacks, and pull three documents before you sign anything: the Palm Beach County property appraiser’s assessed value, the FEMA flood map panel, and the existing home’s finished-floor elevation. In Lantana, this step is non-negotiable. A 1960s CBS home near the Intracoastal can sit low enough that any substantial improvement triggers elevation requirements. We’ll tell you upfront if your project crosses that 50% threshold. You’ll decide: proceed with potential elevation work, scale the ADU down to stay under the limit, or pause and reassess.
Stage 2: Design and permit package (3-6 weeks)
We produce architectural plans, structural drawings, and MEP layouts for county submission. For Lantana builds, we specify stainless or hot-dipped galvanized anchor bolts and hurricane strapping from the start - salt air here eats standard hardware in half the time you’d see in Greenacres or Lake Worth Corridor. You’ll choose your exterior finish, window line, and whether we go stick-built or prefab. We partner with Abodu, Dvele, Mighty Buildings, Boxabl, and Plant Prefab for homeowners who want a faster, factory-controlled build. You’ll also pick your roofing material; we typically spec GAF, CertainTeed, or Owens Corning shingles with full underlayment, or move to tile if we’re matching an existing roof plane.
Stage 3: Site prep and foundation (2-4 weeks)
We clear the build area, run temporary power, and excavate for the foundation. In Lantana’s low-lying areas, this often means engineered fill or stem walls to get above base flood elevation. If your property sits in an AE zone and we’ve triggered full compliance, this is where the elevation work happens. You’ll decide on any utility routing - whether to tie into your existing septic or sewer connection, or run a separate meter for the ADU. Palm Beach County inspectors will visit twice here: pre-pour for rebar and post-tension, then final foundation.
Stage 4: Framing, envelope, and rough-in (4-6 weeks)
Walls go up, roof decking goes on, and we install impact-rated windows and doors - Andersen, Pella, Marvin, Milgard, Jeld-Wen, Simonton, PGT, or CGI depending on your budget and the existing home’s look. We rough in electrical, plumbing, and HVAC. Lantana’s older housing stock often means upgrading the main panel to handle the ADU load; we’ll know this from the first site visit and price it in. County inspectors sign off on framing, electrical rough, and plumbing rough before we close walls.
Stage 5: Finishes and final inspection (3-5 weeks)
Insulation, drywall, flooring, cabinets, countertops, fixtures, and appliances. This is where most of your material choices show up. We install Kohler or Moen plumbing fixtures, and for countertops we offer Cambria, Silestone, or Caesarstone - three tiers of engineered quartz with different warranty terms and edge profiles. Final county inspection covers life safety, energy code, and flood compliance. We do a walkthrough with you, compile the as-built drawings and warranty docs, and hand over keys.
The Options You’ll Choose Between for Your Lantana ADU
- Stick-built vs. prefab: Traditional framing on-site gives you unlimited customization and matches existing architecture seamlessly. Prefab units from Abodu or Dvele cut 6-10 weeks off the build and reduce weather delays, but you’re working within factory dimensions and finish packages. Prefab works well on flat, accessible lots; stick-built wins on tight Lantana infill sites with mature trees or awkward setbacks.
- Foundation type: Monolithic slab is cheapest and fastest where drainage is good. Stem wall or raised slab adds $8,000-$18,000 but gets you above flood elevation without a full crawlspace. Pier and beam is rare here unless we’re building over existing hardscape you want to preserve.
- Window and door grade: Standard impact-rated vinyl from Simonton or PGT meets code at the entry level. Stepping up to aluminum-clad wood from Andersen or Pella gives better sightlines and longer service life in salt air - worth the premium if the ADU faces the water or if you’re renting it long-term.
- Kitchen and bath spec: A wet bar and half-bath keeps the ADU under $110,000 in most Lantana builds. Full kitchen with gas range, dishwasher, and stackable laundry pushes you toward the $150,000+ range. We use Kohler and Moen fixtures as our baseline; both hold up to hard water and tenant turnover.
- Exterior finish: Stucco over CBS matches Lantana’s housing stock. HardiePanel or vertical siding gives a modern look but costs 15-20% more and requires more frequent re-caulking at coastal exposure. We typically recommend stucco with a high-build elastomeric paint for rental ADUs - lower maintenance, better moisture management.
What New Detached ADU Costs in Lantana, FL
A new detached ADU in Lantana runs $90,000-$220,000. Most builds we price land between $110,000 and $160,000 for a 500-650 square foot unit with full kitchen and bath, impact windows, and standard finishes.
Five variables move you up or down that range:
- Size and layout: Every 100 square feet adds roughly $12,000-$18,000. A studio with wet bar is a different project than a one-bedroom with full kitchen and separate HVAC.
- Flood zone compliance: If your property sits in an AE zone and the ADU triggers substantial improvement rules, elevation work can add $15,000-$40,000. We catch this in stage 1 - never after contract.
- Utility connections: Tapping into existing sewer and power is straightforward. Running new service from the street, adding a separate meter, or upgrading a 100-amp panel to 200-amp adds $4,000-$12,000.
- Material grade: Standard vinyl windows, laminate countertops, and fiberglass tub-shower keep costs down. Moving to Pella Architect Series, Caesarstone, and a tiled walk-in shower adds $8,000-$15,000.
- Site conditions: Mature oak roots, zero lot-line setbacks, or a sloped yard toward the Intracoastal require engineered solutions - retaining walls, specialized foundations, or tree protection fencing that adds time and money.
Our written estimates include all labor, materials, permits, and standard inspections. What typically isn’t included: separate utility connection fees charged by the municipality, HOA architectural review fees, or custom landscape restoration beyond basic sod and irrigation repair.
What Lantana Homes Specifically Do to This Job
Lantana’s post-WWII housing stock - concrete block stucco homes from the 1950s through 1970s, many with flat roofs and original jalousie windows - creates a specific challenge for new detached ADU construction. There’s virtually no undeveloped land here; every ADU is an infill project on a lot already occupied by an older structure with aging infrastructure.
The salt-laden air off the Intracoastal Waterway corrodes exposed metal faster than you’d see even five miles inland in Greenacres. We specify stainless steel or hot-dipped galvanized fasteners, anchor bolts, and hurricane strapping on every Lantana build. Skip this and you’ll see rust bleed-through on stucco and compromised structural connections inside of eight years.
Palm Beach County’s wind code, tightened post-Andrew, requires impact-rated openings and verified roof-to-wall connections on all substantial new construction. For a new detached ADU in Lantana, this isn’t an upgrade - it’s code minimum. We price it in from the first estimate.
The most consequential local factor is flood compliance. Lantana’s low elevation puts much of its older housing inside FEMA AE zones. A seasoned contractor pulls the flood map and the property appraiser’s assessed value before any contract is signed. We’ve seen a straightforward 500-square-foot ADU on a 1962 CBS home near Hypoluxo Island quietly cross the 50% substantial improvement threshold, converting the permit into a full flood-elevation event and forcing a raised slab - a $25,000 surprise that kills deals when it surfaces late. We don’t let that happen.
Homeowners often pair a new detached ADU with interior work on the main house. If you’re updating the primary kitchen while we build the unit out back, our Kitchen Design & Layout in Lantana crew can coordinate finishes so both spaces feel connected. Many clients also refresh flooring throughout the property; our Backsplash, Tile & Flooring in Lantana team handles that under the same timeline and single point of accountability.
Serving Lantana, FL - Our Local Coverage Area
We’re based in the Lantana area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked - New Detached ADU in Lantana
From permit approval to final inspection, expect 4-7 months. Prefab units from our partners at Abodu or Dvele can compress this to 3-5 months. The longest variable is Palm Beach County’s permit review, which currently runs 4-8 weeks for ADU plans. Call (844) 665-0162 and we’ll check current turnaround times.
Yes - every new detached ADU in Palm Beach County requires a building permit, electrical permit, plumbing permit, and often a separate floodplain development permit if your property sits in an AE zone. We handle all submissions and inspections as part of our standard process. Our Home Additions & ADU in Lantana page covers the broader permit picture if you’re comparing project types.
Sometimes, but rarely on Lantana’s older lots. Most 1960s-era homes here have undersized electrical panels and original sewer lines that won’t handle a second dwelling. We evaluate this in our first site visit. If the main panel is 100 amps or the sewer line is cast iron with root intrusion, we’ll price the upgrade upfront rather than discover it mid-project.
Usually, but not always. A new detached ADU avoids disrupting your main living space and doesn’t require structural tie-ins to the existing roofline. However, it needs its own foundation, utilities, and weather envelope - costs that a room addition shares with the main house. In Lantana’s flood zones, elevation requirements can swing the math. For a full comparison, our Home Additions & ADU crew can price both paths.
We warranty our workmanship for one year, and every material we install carries its own manufacturer warranty - GAF, CertainTeed, or Owens Corning for roofing; Andersen, Pella, or Marvin for windows; Kohler and Moen for fixtures. We compile all warranty documents in a binder at final walkthrough. For warranty specifics on any brand, ask during your estimate.
Ready to Talk Through Your Lantana ADU?
Call (844) 665-0162 for a free on-site estimate. We’ll walk your property, pull the flood map, check your electrical panel, and give you a written quote with real numbers - no pressure, no surprises after contract. Groundwork Construction Co. serves Lantana and surrounding Palm Beach County from our Fort Lauderdale base.
Written by Raymond Estevez, Owner at Groundwork Construction Co., serving Lantana and South Florida homeowners since our founding.