What a Garage Conversion ADU in Gateway Actually Costs and How Long It Takes
A garage conversion ADU in Gateway typically runs $30,000 to $80,000 and takes 8 to 14 weeks from permit submission to final inspection. That range assumes you’re working within the existing garage footprint, with at least one bathroom and a kitchenette added. The wide spread comes down to four things: whether you’re moving plumbing across a slab, how much electrical capacity your panel has left, what level of finishes you choose, and how smoothly your architectural review goes with the Gateway CDD. Call (844) 638-7249 for a free on-site estimate with real numbers based on your specific garage and floor plan.
How we convert a garage into an ADU in Gateway
Most garage conversions in Gateway follow the same five-stage sequence, though the timeline stretches or compresses depending on the structural changes your specific layout demands. Here’s what to expect from the first walkthrough to handing you the keys.
Stage 1: Site measure, floor plan, and CDD submission. We start by measuring every dimension of your existing garage: slab elevation, ceiling height, door openings, window locations, electrical panel placement, and where your main sewer line runs relative to the garage. That field data becomes a set of as-built drawings. From there, we design a floor plan that meets Florida Building Code for an accessory dwelling: egress windows, minimum room dimensions, a bathroom, a kitchenette with ventilation, and a separate exterior entrance. Before we submit anything to Lee County, we package the plans and finish samples for the Gateway architectural review committee. This is the step that trips up contractors who don’t work in Gateway regularly. The committee meets on a set schedule and needs door styles, exterior colors, window trim profiles, and roofing tie-in details upfront. We handle the entire submission and revision process so you’re not chasing board feedback. This stage runs two to three weeks, depending on committee meeting dates.
Stage 2: Demolition and slab prep. Once the CDD approval letter and the county permit are in hand, we start the physical work. The garage door comes out, the opening gets framed and sheathed, and we saw-cut the slab where new plumbing lines need to run. In a typical Gateway garage built between 1995 and 2005, the slab is a standard 4-inch post-tension pour. Cutting it requires a concrete saw, careful layout to avoid tendons, and an inspection from Lee County before we backfill. If your sewer lateral is on the opposite side of the house, trenching across the slab adds a few days and moves the cost toward the higher end of the range. This stage runs three to five days.
Stage 3: Rough-in: plumbing, electrical, and HVAC. With the slab patched and cured, our plumbing crew runs supply lines and drain-waste-vent piping to the new bathroom and kitchenette locations. The electrician installs a subpanel if your main panel doesn’t have enough open slots, pulls home runs for lighting, outlets, and appliances, and wires in smoke and CO detectors per code. We tie the ADU into your existing central HVAC if the system has the tonnage to handle the added square footage; if it doesn’t, we spec a ductless mini-split, which is common in Gateway garage conversions around the 400-to-500-square-foot size. The rough-in stage takes one to two weeks, capped by a county rough-in inspection covering framing, plumbing, electrical, and mechanical.
Stage 4: Insulation, drywall, and finishes. After the rough-in passes inspection, we insulate the walls and ceiling to Florida energy code minimums, hang and finish drywall, and start installing the visible pieces: LVP or tile flooring, the bathroom vanity and shower surround, kitchenette cabinets and countertop, interior doors, baseboards, and light fixtures. This is the stage where your material selections become reality, and it’s the longest continuous stretch of interior work. Expect three to four weeks here, with a mid-stage walkthrough so you can see the progress and flag any adjustments before the final paint coat goes on.
Stage 5: Trim-out, final inspections, and handover. The last week and a half is all detail work: plumbing trim-out, electrical trim-out, HVAC startup, paint touch-ups, and a thorough cleaning. Lee County sends a building inspector and possibly a separate electrical inspector for the final sign-off. We walk the unit with you to note any items that need attention, and our 730-Day Done Right Promise covers every inch of the work. Once you have the certificate of occupancy, the ADU is ready for tenants, family, or guests.
The options you’ll choose between on a garage conversion ADU
Every garage conversion involves a handful of decisions that change the function and the final cost. Here are the ones that matter most in a Gateway home:
- Flooring: luxury vinyl plank vs. tile. LVP runs $3 to $7 per square foot installed and handles humidity well; it’s warmer underfoot and faster to install. Porcelain tile costs $6 to $12 per square foot installed and is virtually indestructible, but it’s cold and harder on the joints. Most ADUs in Gateway go with LVP in living areas and tile in the bathroom.
- Kitchenette layout: wet bar vs. full galley. A wet bar setup with a small fridge, microwave, and sink meets the ADU requirement and keeps costs down. A full galley kitchen with a range, vent hood, and dishwasher adds $8,000 to $15,000 once you account for the gas line or 240V circuit and the additional cabinet run.
- HVAC: tie-in vs. ductless mini-split. If your main system is less than 10 years old and has enough capacity, tying in costs less upfront. But a dedicated mini-split gives the ADU independent temperature control and avoids straining an aging central unit. For a 450-square-foot garage, a single-zone mini-split runs about $3,500 to $5,500 installed.
- Bathroom: shower-only vs. tub-shower combo. A walk-in shower with a glass enclosure uses less floor space and looks cleaner. A tub-shower combo is the better choice if the ADU will house small children at any point. The cost difference is negligible in materials, but the shower pan and glass add a few hundred dollars over a standard tub.
- Exterior door and window matching. Gateway’s architectural review committee cares about this. We’ll match the door style, window grid pattern, and exterior color to your main house so the committee signs off without a revision cycle. This isn’t optional; we spec it from the start to keep your approval moving.
What a garage conversion ADU costs in Gateway, FL
A garage conversion ADU in Gateway lands between $30,000 and $80,000, with most single-car garage conversions falling in the $40,000 to $55,000 range. Here’s what pushes a project toward the low or high end.
The single biggest variable is plumbing location. If your existing bathroom backs up to the garage wall, the drain tie-in is short and the slab cut is minimal. If the nearest sewer line is 40 feet away on the far side of the house, trenching through the slab and running new waste lines can add $5,000 to $10,000 by itself. The second variable is electrical capacity. A 200-amp panel with open slots handles an ADU without upgrades. A full 150-amp panel that needs a service upgrade to 200 amps tacks on $2,500 to $4,000. The third variable is the garage door conversion. Framing in the opening, sheathing it, and matching the exterior finish to the rest of the house runs $3,000 to $6,000 depending on whether it’s stucco over block or a framed wall with siding. Finish level is the fourth variable: builder-grade vs. semi-custom cabinets, standard vs. stone countertops, basic vs. upgraded plumbing fixtures. The fifth variable is the CDD review itself; revisions requested by the architectural committee add time but rarely add cost unless they require a material change.
Every estimate we write is a fixed-price, line-item quote. It includes the permit package, all labor, all materials, the CDD submission package, and the final cleaning. What it doesn’t include are things you might choose to handle separately: furniture, window treatments, or landscaping around the new entrance. No surprises, no change orders slipped in mid-job. Call us at (844) 638-7249 to schedule a free on-site estimate with exact numbers for your garage.
What Gateway homes specifically do to a garage conversion project
Gateway isn’t unincorporated Lee County. It’s a Community Development District, and that single fact changes how every garage conversion ADU here gets permitted and built. Before Lee County even sees a permit application, the Gateway architectural review committee must approve your conversion plans: the exterior door style and color, the window trim profile, how the former garage opening gets finished, and whether the conversion matches the community’s uniform aesthetic. We handle this submission from the first site visit, including the finish samples and elevation drawings the committee expects. Missing this step is the number-one reason ADU projects stall in Gateway; a contractor who submits straight to the county gets a stop-work notice the moment the committee catches wind of an unapproved exterior change.
The housing stock here also shapes the work itself. Most garages we convert in Gateway are attached, concrete-block structures built between the mid-1990s and about 2008. The slabs are post-tension, which means every saw cut has to be laid out carefully. The tie-in to the main house almost always involves matching stucco texture and barrel-tile roof lines. And because so many Gateway homes took wind damage during Hurricane Ian, we pay extra attention to the tie-in flashing and the structural attachments where the new framed wall meets the existing block. A garage conversion done right here is indistinguishable from original living space, inside and out. If you’re tackling a broader home improvement plan, this project often pairs well with Cabinets & Countertops in Gateway or new Backsplash, Tile & Flooring in Gateway in the main house while we’re already mobilized.
The CDD rules can feel like an extra layer of bureaucracy, but they also protect property values. We know what the committee looks for because we’ve submitted in Gateway dozens of times. Our plans document what the committee wants to see, and we handle the revision cycle if they kick anything back. That’s part of the upfront price, not an add-on fee you discover later. For the full scope of what’s possible, see our Home Additions & ADU in Gateway page.
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Frequently asked - Garage Conversion ADU in Gateway
Plan on 8 to 14 weeks from the day we submit for CDD approval to the day you get the certificate of occupancy. The Gateway architectural review committee meeting schedule is the biggest variable outside our control; submissions that land right after a meeting date wait two to three weeks for the next one. The physical construction, once permitted, runs 6 to 9 weeks for a standard single-car garage conversion. Double-car conversions with larger floor plans and more plumbing fixtures push toward the longer end.
Yes, and you need two layers of approval. First, the Gateway CDD architectural review committee must approve the exterior changes. Second, Lee County Building & Permitting must issue a building permit, which triggers structural, plumbing, electrical, and mechanical inspections at the rough-in and final stages. You cannot legally convert a garage to living space in Gateway without both approvals in hand. We pull every permit and schedule every inspection as part of the job.
Rarely. An ADU in Florida requires at minimum a bathroom with a toilet, sink, and shower or tub. That creates drain, waste, and vent lines that have to tie into your existing sewer lateral somewhere. If the garage wall shares a wall with an existing bathroom, the tie-in can be short and the slab cut minimal. If the sewer line is on the far side of the house, you’re trenching across the garage slab. The exact path determines the cost impact, and we’ll map it during the site measure before you commit. Curious about how this fits into a larger home addition? Our Home Additions & ADU team can walk you through the connection points.
A garage conversion ADU in Gateway costs $30,000 to $80,000, with most single-car conversions landing between $40,000 and $55,000. The spread depends on plumbing distance, electrical panel capacity, finish level, and whether the garage door opening requires extensive framing and stucco matching to meet CDD approval. Call (844) 638-7249 for a free, fixed-price estimate on your specific garage.
Every garage conversion we build is covered by the 730-Day Done Right Promise. If something isn’t right within two full years of completion, we make it right. That covers workmanship on the framing, drywall, flooring, plumbing, electrical, HVAC, and finishes. Material warranties from manufacturers like flooring and fixture brands run separately and typically extend well beyond our workmanship period. No fine print, no chasing subcontractors. One call to (844) 638-7249 and a live person answers, 24/7.
Get a fixed-price estimate for your garage conversion ADU in Gateway
If you’re considering turning your garage into an ADU in Gateway, start with a free on-site estimate. We’ll measure the space, map the plumbing and electrical tie-in points, walk through your finish preferences, and write a line-item quote with a firm price. You’ll know exactly what it costs before you commit a dollar. No design fees, no surprises, and a live person answers when you call (844) 638-7249, day or night. We cover all of Gateway and the broader Lee County area for this work.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Florida homeowners since 2014.