What a Garage Conversion ADU in Lely Resort Actually Costs and How Long It Takes
A garage conversion ADU in Lely Resort turns an existing attached or detached garage into a self-contained living unit with its own entrance, kitchenette, bathroom, and sleeping area. Most projects we build here fall between $45,000 and $130,000, with the typical conversion running 10 to 16 weeks from the day we pull permits to final inspection. Call (844) 638-7249 for a free on-site estimate with a written line-item scope so you see exactly where every dollar goes.
How We Convert a Garage Into an ADU in Lely Resort
The process is methodical because the building department checks every stage. Here’s what the sequence looks like on a typical Lely Resort garage conversion, based on the CBS block construction we work with in this community day in and day out.
Stage 1: Survey, As-Builts, and ARB Submission (Weeks 1-3). Before any tool touches the garage, we pull existing-condition measurements and submit architectural drawings to both Collier County and the Lely Resort Architectural Review Board. The ARB reviews exterior changes - any new door or window openings, the finish and profile, paint color - against the community’s approved palette for your sub-association. This dual-track approval is the single biggest timeline variable in Lely Resort. You decide the floor plan layout, window and door placement, and exterior finish during this stage.
Stage 2: Demo, Slab Prep, and Rough Openings (Weeks 3-5). Once the permit card is posted, we strip the garage interior to the block shell - removing the door, opener, and any drywall. The existing slab gets evaluated for flatness, crack repair, and moisture vapor transmission. Because Lely Resort sits on a coastal plain where the wet-season water table can rise within 18 to 24 inches of grade, we test slab moisture before committing to flooring assemblies. We cut new rough openings for windows and the entry door, and the plumbing trench is saw-cut into the slab for the bathroom and kitchenette drain lines.
Stage 3: Rough-In - MEP, Framing, and HVHZ Openings (Weeks 5-8). Plumbers stub out supply and drain lines. Electricians run the subpanel feed, branch circuits, and can lights. The mini-split HVAC line set gets routed. This is when we install impact-rated windows and doors that meet Florida’s High-Velocity Hurricane Zone requirements - a non-negotiable cost driver on every permitted ADU in Collier County. Interior partition framing goes up, and the bathroom gets a pre-slope and waterproofing before the shower pan is poured. You’ll choose fixtures and finishes by the end of this stage so materials are on-site for trim-out.
Stage 4: Insulation, Drywall, and Close-In (Weeks 8-11). Closed-cell spray foam goes into the block wall furring cavities and ceiling joists - we spec this over batts in Lely Resort because the vapor-closed cell structure handles southwest Florida humidity better. Drywall is hung, taped, and textured. The bathroom gets cement board and a waterproof membrane. Exterior stucco patch and paint are matched to the ARB-approved color for your sub-association. At rough-in inspection, the county checks the mechanical, electrical, plumbing, and framing before we close walls.
Stage 5: Trim, Fixtures, Flooring, and Final Inspection (Weeks 11-16). Cabinets, countertops, trim, doors, and baseboard go in. The mini-split condenser is commissioned. Flooring - typically luxury vinyl plank or tile on the slab - is installed. The kitchenette gets its sink, faucet, and under-counter fridge. Bath fixtures, the shower glass, and the vanity are set. We walk the unit with you for a punch list, then stand with the county inspector for final sign-off. The job closes when you have a certificate of occupancy in hand and a fully functioning second dwelling.
Throughout the build, your single point of contact is a superintendent who knows the ARB submission requirements and the Collier County inspection workflow. If this garage conversion is part of a full Home Additions & ADU in Lely Resort scope - say you’re adding square footage beyond the garage footprint - we phase the work so the ADU can be locked off and lived in while the addition continues.
The Choices That Shape Your Garage Conversion ADU
Every garage is different, and the decisions you make about layout, systems, and finishes move the final number. Here are the big ones.
- Attached vs. detached garage. An attached garage shares at least one wall and often the roofline with the main house, which simplifies tying into existing electrical and plumbing - costs track toward the lower end of the range. A detached garage needs its own subpanel feed trenched from the main service, a separate water lateral from the street or well, and sometimes a new sewer tap, which pushes the budget toward the upper end.
- Plumbing scope. The single biggest cost swing in any garage conversion is whether you need a full bathroom with a shower, a kitchenette with a sink, or both. Running a 3-inch drain line through an existing slab in Lely Resort - where the wet-season water table sits just under the footing - often means cutting and removing concrete, digging deeper than inland jobs, and backfilling with select fill to prevent settlement. A powder bath costs far less than a full bath with a tiled shower.
- HVAC system. Most Lely Resort garage conversions get a ductless mini-split heat pump sized for the square footage. If the main house has a newer high-SEER system with enough capacity, we can sometimes extend a ducted branch - but the ARB and your sub-association CC&Rs may limit where the outdoor condenser can sit, so placement gets reviewed during the ARB submission.
- Flooring and moisture mitigation. Every garage slab in Lely Resort gets a moisture-vapor emission test. If the reading comes back high - common on older CBS villas in the Players Club and Greenlinks sections - we spec a two-part epoxy vapor barrier before the finished floor goes down. Skipping this step leads to buckled LVP and mold inside of two wet seasons. Tile on a decoupling membrane is the most forgiving option; floating LVP with a built-in pad is the most budget-conscious.
- Window and door package. Any new opening cut into a CBS wall requires an impact-rated assembly with a product approval number on file with Collier County. Andersen and Pella both manufacture HVHZ-compliant units we use regularly. The size and quantity of windows you want - and whether you opt for a sliding glass door to a small patio - moves the line item meaningfully.
We use concrete-products suppliers like Quikrete and Sakrete for slab repair and grout work, and when the ADU scope calls for precast elements - such as a small stoop or landing - Oldcastle has products that speed the finish stage. If you’re also thinking about interior finish work once the drywall is up, homeowners often pair this phase with Backsplash, Tile & Flooring in Lely Resort so the same crew handles the wet areas from rough to finish.
What Garage Conversion ADU Costs in Lely Resort, FL
A garage conversion ADU in Lely Resort runs $45,000 to $130,000, with the typical single-car attached-garage conversion landing between $55,000 and $85,000 when built with a full bath, kitchenette, and mini-split HVAC. The range is wide because no two garages are in the same condition, and the permitting path through the ARB and county adds hard costs that don’t exist in unincorporated areas.
Here’s what pushes a job toward the low or high end of that range:
- Square footage and layout complexity. A 250-square-foot single-car garage with a simple rectangular plan costs less than a 500-square-foot two-car garage that needs structural beams to clear-span the living area.
- Slab condition and plumbing depth. A slab with minimal cracking and low moisture vapor emission needs less prep. Lely Resort’s high seasonal water table adds excavation depth and dewatering time on any bathroom drain that runs under the slab, which adds labor and material cost.
- Electrical service capacity. If the existing main panel has open breaker slots and enough ampacity, adding a 60-amp subpanel to the ADU is straightforward. If the panel is maxed out, a service upgrade adds $3,500 to $6,000 to the project.
- Interior finish level. Builder-grade cabinets, a fiberglass shower pan, and laminate counters keep the budget lower. Custom cabinetry, a tiled walk-in shower with a glass enclosure, quartz counters, and solid-core interior doors push it higher. Many Lely Resort homeowners choose a finish level consistent with the main house, especially in estate-home sections like Majorca.
- ARB-required exterior modifications. If the garage door opening becomes a wall with a window and stucco patch, the ARB requires the finish and paint to match the existing elevation exactly - often meaning a full re-paint of that wall plane to avoid a visible seam. This is a small line item but it’s unique to master-planned communities with architectural review.
Every estimate we write is a fixed-price, line-item scope - not an allowance range you have to hope holds. It includes all permits, ARB submission documents, materials, labor, and the final county inspection. The 730-Day Done Right Promise covers the workmanship on everything we build. What it doesn’t include are change orders you initiate after permits are issued - those get priced and approved separately so the original number stays honest. Call (844) 638-7249 for a free on-site estimate, and you’ll have a written proposal in hand, not a verbal ballpark.
What Lely Resort Homes Specifically Do to This Job
Garage conversions in Lely Resort run on a different rulebook than conversions in unincorporated Collier County. Every exterior modification - even infilling a garage door opening with a stucco wall and a new window - must clear the community’s Architectural Review Board before the county will issue a building permit. The ARB enforces a tightly controlled palette of exterior colors, window profiles, and stucco textures tied to your specific sub-association. We’ve seen out-of-area crews submit a county-compliant window that isn’t on the ARB’s approved product list and get a stop-work notice within days. The dual-approval workflow adds two to four weeks to the front end of the project and means your contractor needs to be fluent in ARB submission packages - not just county permitting.
The housing stock itself shapes the work. Most garages we convert are concrete-block shells built between the mid-1990s and the 2010s. The older CBS structures in sections like the Classics and the Masters often have slab-edge settlement and hairline cracking from two decades of wet-dry cycling in the expansive coastal soil. We evaluate every slab before we design the bathroom layout, because a drain-line trench cut through an already-stressed slab edge can propagate cracking if the repair isn’t doweled and epoxied correctly. Newer coach homes in the still-building phases of the neighborhood have cleaner slabs but often share a fire-rated demising wall with an adjacent unit, which limits where we can cut new openings without triggering a structural engineering review.
The HVHZ requirements touch every part of the conversion. Windows, the entry door, and any sliding glass door must carry a Florida Product Approval number and be installed to the county’s wind-load details. The mini-split condenser needs hurricane tiedowns. These aren’t optional upgrades - they’re code minimums that every permitted ADU in Lely Resort must meet, and they’re part of why the base cost for a compliant conversion starts where it does. If the conversion scope grows into a larger addition, our Home Additions & ADU team handles the full structural and envelope work under the same permit set.
Serving Lely Resort, FL - Our Local Coverage Area
We’re based in the Lely Resort 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 Questions About Garage Conversion ADU in Lely Resort
Plan on 10 to 16 weeks from permit issuance to final inspection. The front-end ARB review adds two to four weeks before the county permit is even in hand. The actual construction - demo through trim - runs eight to twelve weeks on a typical single-car garage conversion, assuming no change orders and no weather delays that stall the stucco or exterior paint stages during the wet season.
Yes, absolutely. You need both Collier County building permits and Lely Resort ARB approval. Converting a garage into habitable space changes the use and occupancy classification of the structure, which triggers plan review for structural, electrical, plumbing, mechanical, and HVHZ wind-load compliance. Skipping permits creates a non-conforming unit that can stall a future home sale - title companies and insurers in Florida flag unpermitted living space routinely. Call (844) 638-7249 and we’ll walk you through the full approval path before you spend a dollar on design.
If you want a bathroom or kitchenette, plumbing has to get under the slab, through the wall, or up from a raised floor assembly. In Lely Resort’s CBS construction, most garages are on-grade slabs, so a drain-line trench through the concrete is the most common method. We saw-cut, excavate, and patch to code - and because the local water table is high, we often excavate slightly deeper than the minimum to bed the pipe in select fill that won’t shift. A powder bath with the toilet on an upflush macerating system can avoid deep slab cuts, but the ARB and county still review it as a plumbing fixture.
Not unless you change the scope. Our estimates are fixed-price and line-itemed - you see the exact cost for every phase before you sign. If we open a wall and find something nobody could have seen (a corroded electrical feed, termite damage at the sill plate), we document it, price the fix, and get your approval before doing a dollar of extra work. We don’t hand you a surprise bill at the end. The 730-Day Done Right Promise covers the work we contracted for - and it’s in writing.
A garage conversion repurposes an existing structure, so the shell, slab, and roofline are already there - the cost is concentrated on interior build-out, systems, and bringing the envelope up to habitable-space code. A detached ground-up ADU starts with site work, foundation, block walls, trusses, and a new roof, so the cost is higher - typically $90,000 to $220,000 in Lely Resort. Conversions move faster and cost less, but they’re limited to the garage’s existing footprint. If you’re weighing both options, we can price them side by side on the same site visit. Homeowners who go the conversion route often add interior finish touches afterward with our Cabinets & Countertops in Lely Resort services to match the ADU’s kitchenette and bath to the main house.
Get a Fixed-Price Estimate for Your Garage Conversion ADU in Lely Resort
We’ll walk the garage with you, measure, test the slab moisture, check the panel capacity, and talk through the floor plan that makes sense for your lot. Then you’ll get a written, line-item proposal - not a ballpark, not an allowance range. Derek Hollenbeck and the Groundwork Construction Co. team have built garage conversions across Lely Resort’s sub-associations and know the ARB submission process cold. Call (844) 638-7249 to schedule your free on-site estimate. A live person answers - no voicemail, no callback wait.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., building garage conversions and ADUs throughout Lely Resort since 2014.