What a Garage Conversion ADU in Lehigh Acres Really Takes (and What It Costs)
Converting a garage into a fully permitted accessory dwelling unit in Lehigh Acres runs between $45,000 and $130,000 and typically takes 10 to 16 weeks from demolition to final inspection. The biggest variables are whether you’re converting an attached garage in a 1970s CBS home or a detached structure from the 2000s boom era, and how much plumbing, electrical, and structural work the existing slab and framing can support without a full re-engineer. If you’re weighing the numbers on a garage conversion in Lehigh Acres, call us at (844) 638-7249 for a project-specific estimate built from a site walk, not a spreadsheet guess.
How We Convert a Lehigh Acres Garage Into a Legal ADU
Every conversion follows a sequence that’s predictable once the existing structure is understood. Here’s what the five stages look like on the ground here, and what you’ll need to decide at each one.
Stage 1: Structural and slab assessment (Days 1-3). Before any design work starts, we open walls at key load points and core the slab to verify thickness, reinforcement, and moisture conditions. In Lehigh Acres, where the water table sits high and summer rain ponds on flat lots, slab moisture and vapor transmission are make-or-break variables. A slab that passes gets a vapor barrier and engineered flooring plan. One that doesn’t may need a raised subfloor or full replacement, easily the single largest cost swing on a garage conversion. You’ll decide on flooring direction once we have moisture readings in hand.
Stage 2: Permit set and Lee County submittal (Days 4-21). We prepare architectural drawings, structural calculations, and MEP plans showing the conversion as a distinct dwelling unit with its own entrance, kitchen, bath, and egress. Lee County wants to see the ADU separated from the main house by a one-hour fire-rated assembly where walls are shared, plus dedicated parking and utility metering or a clear sub-metering plan. We handle the submittal and revisions. This is the stage where you’ll lock in the floor plan and fixture locations, because changing them after permits issue adds weeks.
Stage 3: Demolition and rough-in (Days 22-45). The garage door comes out and gets framed into a wall with windows and an entry door matching the main house’s architecture. We trench the slab for new drain lines, run supply plumbing and a subpanel if the ADU gets its own electric service, install HVAC ducting or a mini-split, and insulate to current Florida energy code. At rough-in inspection, Lee County checks framing, nailing patterns, strapping, and fire-blocking before any drywall goes up. This is your last chance to add circuits, relocate a wall, or change the kitchen layout without a change order.
Stage 4: Drywall, trim, and finishes (Days 46-70). Once the rough-in passes, insulation and drywall go in, followed by flooring, cabinets, countertops, plumbing fixtures, lighting, and interior door hanging. By the end of this stage the unit is lockable and temperature-controlled. You’ll walk through with our project lead to confirm finish details match the spec sheet. If you’re adding Cabinets & Countertops in Lehigh Acres with a specific door profile or edge detail, this is when those get final verification.
Stage 5: Final inspections and certificate of occupancy (Days 71-90). Lee County inspects the completed unit for building code, electrical, plumbing, and mechanical compliance. Once we have a signed-off final and a CO, the ADU is legal to rent or occupy. If the conversion was part of a full Home Additions & ADU in Lehigh Acres scope, we sequence the CO around the broader project’s completion so nothing holds up move-in. The 730-Day Done Right Promise starts the day the county signs off.
The Options You’ll Choose Between on a Garage Conversion
Every garage conversion has a handful of decisions that define the final product and its maintenance profile. These are the ones our Lehigh Acres homeowners weigh most often.
- Attached vs. detached conversion. An attached garage shares at least one wall and usually the roof structure with the main house. That saves on foundation and framing cost but requires fire separation and sound attenuation between the two units. A detached garage conversion is structurally independent, which simplifies fire code and gives more privacy, but it needs its own full utility trenching from the street or main house, which can add $8,000 to $20,000 in Lehigh Acres depending on distance and soil conditions.
- Mini-split HVAC vs. extending the main system. A multi-zone mini-split gives the ADU independent temperature control and avoids ducting complexity in a small footprint. Extending the main home’s central system can work for attached conversions, but only if the existing unit has enough tonnage headroom, which many 15-to-20-year-old systems in Lehigh Acres do not. Mini-splits run $4,000-$9,000 installed; a main-system extension typically runs $2,500-$5,000 but may force a larger replacement sooner.
- Kitchenette vs. full kitchen. A kitchenette with a sink, microwave, and under-counter fridge meets code for an ADU and keeps plumbing work contained. A full kitchen with a range, dishwasher, and vent hood needs a dedicated 40-amp circuit, makeup air if the unit is tightly sealed, and a gas-line rough-in or propane accommodation if you’re not all-electric. The delta is usually $8,000-$18,000 when you factor in electrical, plumbing, cabinetry, and countertop surface. We often source cabinet lines through KraftMaid and can pair the layout with Backsplash, Tile & Flooring in Lehigh Acres for a cohesive finish.
- Slab-on-grade moisture management. Because of the high water table under Lehigh Acres, we always spec a 10-mil minimum vapor barrier under any new flooring and often recommend an epoxy moisture-mitigation system before tile or LVP goes down. Skipping this step on a slab that reads above 85% relative humidity in a calcium-chloride test leads to cupped planks and grout failure within 18 months. It’s a $1,200-$2,400 line item that pays for itself immediately.
What a Garage Conversion ADU Costs in Lehigh Acres, FL
A garage conversion ADU in Lehigh Acres runs $45,000 to $130,000, with most attached conversions on 2000s-era homes landing between $65,000 and $95,000 and detached conversions on legacy 1960s-70s lots pushing toward the high end. Every estimate we write is a fixed-price, line-item document. No change orders unless you change the scope. Here is what moves the number.
Square footage. A single-car garage around 250 square feet costs less to convert than a two-car at 400-500 square feet, but the cost per square foot drops as the footprint grows because the expensive items (kitchen, bath, service panel, utility trench) get amortized over more livable area.
Slab condition. If the existing slab is cracked, un-level beyond ¼-inch in ten feet, or moisture-compromised, you’re looking at slab replacement or a raised subfloor. That can add $7,000 to $18,000 before a single wall goes up. In Lehigh Acres, where seasonal water ponding is common on flat lots, we test every slab before quoting.
Plumbing and electrical scope. A garage with plumbing stubbed to the wall and a subpanel with 60+ amps available is much cheaper to convert than one that requires trenching the slab for a new drain line and upgrading the main service from 100A to 200A. Service upgrades alone run $3,500-$5,500 in Lee County.
Finish level. Builder-grade cabinets, laminate counters, and standard fixtures keep finishes in the low $40s per square foot range. Semi-custom cabinets, quartz or solid-surface counters, and tile showers push into the $70s per square foot. Our team uses upfront pricing anchored to real material quotes from partners like Quikrete for any slab work and Oldcastle for block and hardscape tie-ins around the new entrance.
Permit and impact-fee scope. Lee County charges plan-review and permit fees based on valuation, and an ADU conversion may trigger school and transportation impact fees if it’s classified as a new dwelling unit rather than an interior remodel. We include those numbers in the estimate so they don’t hit as a surprise at submittal.
The estimate you get from us covers all labor, materials, permits, and a scheduled project timeline. What it does not cover is scope you add later. Call (844) 638-7249 and we’ll walk the site and put numbers to each variable for your specific garage.
What Lehigh Acres Homes Specifically Do to This Job
The flat pine-flatwoods geography that defines Lehigh Acres means every garage conversion starts with a water-table conversation. Unlike Cape Coral’s canal-drained grid, most lots here rely on sheet flow and shallow swales, so summer rain ponds against slab edges and garage door openings. That reality forces us to address site grading and door-threshold waterproofing before interior work begins. On the 1960s-70s CBS homes that make up the original retirement-market stock, we routinely find slabs poured with minimal reinforcement and no vapor barrier underneath, so a garage-to-ADU conversion on those lots almost always requires a moisture-mitigation system and often a partial slab overlay to create a level, dry floor plane. On the 2003-2008 boom-era tract homes, the slab and framing are typically in better shape, but deferred maintenance from foreclosure years means roof leaks at the garage-to-house tie-in are common and need repair before insulation and drywall can start. Both scenarios are fixable; neither is unusual. The post-Hurricane Ian rebuild surge means Lee County plan review load is still heavy, so we factor an extra 10-14 days into the permitting stage compared to pre-2022 norms and communicate every status change so you’re never in the dark. If you’re converting a garage on one of the legacy platted lots where the access road was never paved, we coordinate pre-permit with Lee County Public Works on access verification and utility stub locations, because building an ADU on a lot with a contested right-of-way is a delay nobody wants.
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Frequently Asked Questions About Garage Conversion ADU in Lehigh Acres
Plan on 10 to 16 weeks from the day demolition starts until final inspection signs off, with permitting adding roughly three to four weeks before a hammer ever swings. Attached conversions on post-2000 homes trend toward the shorter end; detached conversions on 1970s slabs or lots needing utility trenching trend longer. Lee County inspection scheduling has been running about a week out since Hurricane Ian reconstruction ramped up, and we lock in inspection dates as soon as each phase is ready.
Yes, without exception. Lee County classifies a garage-to-ADU conversion as a change of occupancy that requires building, electrical, plumbing, and mechanical permits, plus a certificate of occupancy upon final approval. Doing the work without permits risks code enforcement action, insurance denial on any related claim, and a disclosure problem when you sell. Every conversion we do goes through the full permit path and includes the paperwork in the project file we hand you at closeout.
It depends on the garage’s current utility stub locations and the panel’s headroom. If the garage already has water and drain lines in the wall or slab (rare but not unheard of in Lehigh Acres homes built with a utility sink), you may be able to design the kitchen and bath around those tie-ins and avoid slab trenching. If the existing panel lacks two open breaker slots and enough amperage to carry a kitchen appliance circuit and mini-split, a subpanel or service upgrade becomes unavoidable. We tell you which one applies during the structural assessment so there’s no guessing.
Every garage conversion ADU we build is covered by Groundwork Construction Co.’s 730-Day Done Right Promise. If something isn’t done right within two full years of the certificate-of-occupancy date, we make it right at our expense. That goes beyond the standard one-year workmanship warranty most contractors in the Home Additions & ADU space offer, and we back it with a company that has been answering its phones live, 24/7, for over 42 years. Manufacturer warranties on installed products run separately and we register every one on your behalf.
Between $180 and $325 per finished square foot is the realistic range for a code-compliant garage conversion ADU in Lehigh Acres, with the low end reflecting a simple studio layout on a good slab and the high end reflecting a detached structure with full kitchen, custom finishes, utility trenching, and moisture remediation. To get an exact number based on your garage’s condition and your finish selections, call (844) 638-7249 to schedule a free on-site estimate.
Get a Fixed-Price Estimate for Your Garage Conversion ADU in Lehigh Acres
If you’re ready to see what your garage can become, we’ll walk the site, answer every question, and give you a written, line-item estimate before you commit to anything. The estimate is free, the pricing is upfront with no hidden add-ons, and the call is answered by a live person, any hour. Reach us at (844) 638-7249 to schedule your estimate for a garage conversion ADU in Lehigh Acres. From foundation to finish line, we make sure it’s built to last and backed in writing.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Lehigh Acres and the surrounding communities.