What a garage conversion ADU in Bonita Springs actually costs and how long it takes
In Bonita Springs, converting an existing attached or detached garage into a legal accessory dwelling unit typically costs $30,000 to $80,000 and takes 8 to 16 weeks from permit approval to final inspection. A straightforward studio conversion with a kitchenette and bathroom stays near the low end, while a full one-bedroom layout requiring structural reinforcement, impact-rated windows, and separate utility runs pushes into that $65,000 to $80,000 range. Call (844) 638-7249 for a free on-site estimate specific to your garage’s footprint and existing condition.
What you’re actually choosing between when you convert a garage into an ADU
The framing, drywall, and flooring are the straightforward part. The decisions that shape the budget and the finished space happen earlier, and they fall into a few categories where one route makes sense for a rental unit and another makes sense for housing an aging parent. Here is what our team walks every Bonita Springs homeowner through before we price anything.
- Floor plan: open studio versus separate bedroom. An open studio with a kitchen along one wall keeps plumbing concentrated and cost down. A one-bedroom plan with a framed interior wall adds square footage cost and often triggers a second egress requirement. If you intend to rent the unit long-term, a separate bedroom typically commands higher rent in Bonita Springs, especially west of 41 where seasonal demand runs strongest.
- Plumbing scope: tie into the main house or run a separate lateral. Most garages sit on the home’s existing slab, and tying the new bathroom and kitchen drains into the main line is the most common path. If your garage is detached and set below the main sewer elevation, an ejector pump or separate sewer lateral becomes necessary. That single decision can add $4,000 to $9,000 to the job, and it is one we flag in the first walkthrough.
- Electrical upgrade: subpanel versus new service. A garage conversion ADU with a mini-split HVAC, kitchen appliances, and a stacked washer/dryer will need a 100-amp subpanel at minimum. Older Bonita Springs homes in neighborhoods like Bonita Shores often still run on a 150-amp main service, and adding a full ADU sometimes requires upgrading the entire service to 200 amps. We price both scenarios so you know the range before committing.
- Windows and doors: impact-rated or nothing. Florida code requires impact-rated glazing or shutters in new living space. We use Andersen and other impact-rated window packages that meet Miami-Dade HVHZ standards. A standard sliding glass door versus a set of French doors versus a sliding impact-rated door changes the look and the cost materially, and we order early because lead times on custom impact-rated units still run 6 to 10 weeks.
- Flooring and finishes: glue-down LVP versus tile. Luxury vinyl plank handles Bonita Springs humidity without warping and stays cooler under bare feet than tile in an air-conditioned space. Large-format porcelain tile costs more to install but resists scratching better if the unit will be rented to tenants with pets. We stock samples from Quikrete floor-leveling products for slab prep and a range of LVP and tile options so you can choose in one sitting.
How we take a garage conversion ADU from permit to move-in ready in Bonita Springs
Every job starts with the same question: what does Lee County want to see, and what will the specific property actually allow? Garages in AE and VE flood zones carry stricter rules than those in X zones, and a substantial number of Bonita Springs properties fall into the AE designation. We pull the property’s flood map, confirm the base flood elevation, and build the permit package around that reality before a single trade shows up.
Stage one: as-built survey, design, and permit submittal. Week 1 to 3. We measure the existing garage, document slab elevation, door openings, roof tie-downs, and the location of the main electrical panel and sewer cleanout. Our designer works up a floor plan with the kitchen, bath, and living space you chose. If the garage is in a community like Pelican Landing or Bonita Bay, we also pull the HOA architectural guidelines before submittal because those can override or add conditions beyond county code. The permit package goes into Lee County and we track it through plan review.
Stage two: demolition, slab prep, and rough-in. Week 3 to 5. The garage door comes out, the opening gets framed and sheathed to match the existing wall assembly, and the impact-rated window or sliding door that replaces it gets set. If the slab needs leveling, we use Sakrete self-leveling underlayment to bring it flat before any wall plates go down. Plumbing rough-in for the bathroom and kitchen happens next, followed by the electrical subpanel and HVAC mini-split line set. The rough framing, rough electric, and rough plumbing all get inspected at once, which keeps the schedule moving.
Stage three: dry-in, insulation, and drywall. Week 5 to 7. Exterior walls get insulated to Florida Energy Code requirements. Interior walls get batt insulation for sound control, especially the wall shared with the main house. We hang, tape, and float drywall, then spray texture and prime. The mini-split indoor unit gets mounted and commissioned so the space stays conditioned while finish work proceeds.
Stage four: finishes, fixtures, and cabinetry. Week 7 to 12. Flooring goes down, the kitchenette cabinetry and countertop get installed, bathroom tile and vanity go in, light fixtures and plumbing fixtures get trimmed out. This is the stage where your material selections earlier in the job determine pace: stock cabinetry is ready in days, while a custom cabinet run can take four weeks. The same timing spread applies to countertops. We sequence orders so material lead time never halts the job.
Stage five: final inspections and punch list. Week 12 to 16. Lee County inspects the electrical, plumbing, mechanical, and building final. We walk the unit with you, note every item that needs attention, and resolve the full punch list before we consider the job complete. Every garage conversion ADU we build carries the 730-Day Done Right Promise, so any issue that surfaces after move-in gets addressed with no runaround.
Larger home addition and ADU scopes are part of what we do as a Home Additions & ADU in Bonita Springs contractor, and this garage-focused work is built to the same permit-and-inspection standard.
What a garage conversion ADU costs in Bonita Springs, FL
A legal garage conversion ADU in Bonita Springs runs $30,000 to $80,000. That is the full-project range, and it assumes a structurally sound existing garage on a conforming slab. The low end covers a studio layout with a compact kitchenette, a three-piece bath, and mid-grade finishes. The high end reflects a fully separated one-bedroom ADU with its own electrical service, impact-rated window package, mini-split HVAC, and higher-spec kitchen and bath finishes.
The five variables that push a specific job toward one end or the other:
- Flood zone designation. Garages in AE or VE flood zones in Bonita Springs often require the finished floor to sit at or above base flood elevation. If the existing slab is too low, we need to raise it or pursue a dry-floodproofing approach where the county allows it. This single variable can add $8,000 to $20,000.
- Electrical service capacity. A home with a 200-amp panel can usually absorb the ADU load with a subpanel. A 150-amp service on an older home may need a full upgrade, adding $2,500 to $4,500.
- Sewer lateral distance and elevation. A garage at the back of a deep lot with no existing drain nearby costs more to plumb than one sharing a wall with the main house’s wet wall. Detached garages set below the street sewer line can require a grinder pump, which adds $3,000 to $5,000.
- Impact-rated opening sizes. A single impact-rated entry door costs less than a six-foot sliding impact-rated door. The difference in material cost alone can be $800 to $2,200 per opening, and our upfront pricing reflects the specific units your plan calls for.
- Finish grade. Stock cabinetry versus custom, basic laminate countertops versus quartz, standard LVT versus wide-plank LVP, and a fiberglass shower pan versus a tiled shower base. These choices move the final number by $5,000 to $12,000 on a garage conversion.
Every estimate from Groundwork Construction Co. comes as a written line-item quote so you see exactly where the money goes. There are no change orders unless you change the scope. Call (844) 638-7249 to schedule a free, no-pressure estimate. We also offer 0% financing for 18 months and $1,000 off projects over $10,000, which can make the difference in starting now versus waiting.
What Bonita Springs homes specifically do to a garage conversion ADU project
No other market in Lee County has been shaped by Hurricane Ian the way Bonita Springs was. The Imperial River flooded entire neighborhoods in September 2022, and the FEMA substantial damage determinations that followed rewrote the rules for what a permit triggers. When we pull a permit for a garage conversion on a pre-2000 home west of I-75, we first confirm the property’s current FEMA substantial damage status. If the county has already determined the structure is substantially damaged, a renovation permit can legally require the entire home to be elevated to current base flood elevation. That turns a $45,000 garage conversion into a much larger Home Additions & ADU project, and we tell you that before we file anything.
The older concrete-block homes in Bonita Shores and the neighborhoods off Shangri-La Road were built before Florida’s post-2004 wind codes, and their existing garage slabs, tie-downs, and wall-to-roof connections commonly need reinforcement to meet current standards for new living space. The high water table across the coastal plain also means underground plumbing and electrical conduit work has to account for soils that stay saturated through the June-to-October wet season. We schedule rough-in work during drier stretches where possible and spec materials that handle the moisture long-term.
Our Bonita Springs team knows which HOAs in Pelican Landing and Bonita Bay need architectural review board approval before a garage conversion permit gets filed, and we handle that paperwork as part of the project. Some HOAs restrict garage-to-living-space conversions if the garage was counted toward the community’s required off-street parking minimum. We check the plat and CC&Rs before design starts.
Homeowners in Bonita Springs often pair a garage conversion with interior finish updates. While we are pulling permits and running new electrical, it is common for customers to ask us about Cabinets & Countertops in Bonita Springs for the main house kitchen, or about new Backsplash, Tile & Flooring in Bonita Springs in the main house bathrooms. We can sequence both scopes under one permit package and one crew.
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Frequently asked about garage conversion ADUs in Bonita Springs
Yes. Converting a garage into living space in unincorporated Lee County or within the City of Bonita Springs requires a building permit, and the work must pass structural, electrical, plumbing, and mechanical inspections. We pull the permit, schedule every inspection, and do not treat this like a handyman job that flies under the radar. Legally permitted ADUs also preserve your home’s resale value and insurability in the Bonita Springs market.
Most garage conversions in Bonita Springs take 8 to 16 weeks once the permit is issued. The permit review itself typically takes 3 to 6 weeks depending on Lee County’s current plan-review backlog. Flood zone determinations, HOA approvals, and material lead times on impact-rated doors and windows are the three things that extend the schedule, and we map all of them before we start so you know the finish date upfront. Call (844) 638-7249 and we will give you a timeline specific to your project.
Sometimes, but not often. An attached garage that shares a wall with the main house’s kitchen or bathroom can sometimes tie into existing drain and vent stacks with minimal slab cutting. A detached garage almost always requires new underground plumbing runs and an electrical feeder from the main panel. Either way, county code requires a bathroom and kitchenette in an ADU to have their own dedicated circuits and plumbing vents. We show you both scenarios and the cost difference at the estimate stage.
A garage conversion ADU in Bonita Springs costs $30,000 to $80,000 depending on size, flood zone requirements, finish level, and how much new utility infrastructure the job requires. The most common finished budget we see for a one-bedroom unit with a full bathroom, kitchenette, and impact-rated windows on an attached garage sits between $48,000 and $62,000. Our estimates are line-item quotes, not ballparks. Call (844) 638-7249 to schedule a free on-site walkthrough.
Every garage conversion ADU we build is covered by the 730-Day Done Right Promise. If something is not right, we make it right for two full years after completion. That covers workmanship across framing, drywall, flooring, plumbing, electrical, HVAC, and finishes. Manufacturer warranties on windows, doors, appliances, and fixtures run separately and typically extend 5 to 25 years. No other contractor we know of in the Bonita Springs market puts a two-year workmanship guarantee in writing on garage conversions.
Get a free on-site estimate for a garage conversion ADU in Bonita Springs
If you are serious about converting your garage into a legal, well-built ADU, let us walk the space with you. We measure, check the flood zone, map the utility paths, and give you a written line-item price so you can decide with real numbers. It costs nothing and comes with no sales pressure. Call (844) 638-7249 to schedule your estimate. Live person, 24/7, no voicemail.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Bonita Springs and all of Lee County.