What a Junior ADU & Interior Conversion Actually Costs and Takes in Fort Myers
A junior ADU and interior conversion in Fort Myers typically runs between $45,000 and $130,000, with most projects finishing in 10 to 16 weeks. This work converts existing interior square footage, often an attached garage, a large bonus room, or a underused den, into a self-contained living unit with its own kitchenette, bathroom, sleeping area, and separate entrance. Call (844) 638-7249 to walk through your floor plan with us. We’ll give you a written, line-item estimate so you know exactly where every dollar lands.
How we build out a junior ADU from your existing space
Every conversion follows the same discipline, but no two Fort Myers homes start from the same point. Here’s the sequence we work through, stage by stage, so you know what to expect and when you’ll need to make decisions.
Days 1-3: As-built verification and permit lock-down. We pull dimensions on everything: wall locations, ceiling height, plumbing chase access, electrical panel capacity, and window rough openings. In Fort Myers, the permit package for an interior conversion requires floor plans, structural load calcs if we’re moving or cutting any wall, and an energy compliance path under the Florida Building Code. We submit to Lee County or the City of Fort Myers Building Department depending on your address. Approval timelines vary, but we keep the job moving by ordering long-lead materials during plan review.
Week 1-2: Demolition and rough-in prep. Non-load-bearing walls come down. We open the ceiling only where we need to run new circuits, drain lines, or vent stacks. If the space was a garage, we cut the slab for the bathroom and kitchenette drain tie-ins and pull new 20-amp circuits for the kitchenette appliances. This is the stage where the full scope comes into focus: once we see what’s inside the walls and under the slab, we can confirm whether the estimate holds or whether we found something that needs a conversation. We always call you before any change order, period.
Weeks 3-6: Rough-in and first inspection. Plumbing, electrical, and mechanical go in. We set the shower pan, run PEX supply lines, install the exhaust fan duct to the exterior, and pull the subpanel if the existing panel doesn’t have enough headroom. The rough-in inspection happens here: a Lee County inspector checks framing, strapping, blocking, and all rough MEP before we close anything up. This is the single most important inspection in an interior conversion because it locks in the structural and life-safety elements before insulation and drywall cover them.
Weeks 7-10: Drywall, trim, and finishes. Insulation goes in, drywall hangs and finishes, and we set doors, baseboards, and casing. Your floor material choice matters here: tile takes longer than LVP because of thinset cure time. If you’re doing a kitchenette with a wet bar sink and undercounter fridge, the cabinet install and countertop template happen during this window. Paint goes on last, after trim, so we get clean lines.
Weeks 10-16: Fixtures, final inspection, and walkthrough. We set the toilet, vanity, light fixtures, switches, and the mini-split or PTAC unit if the existing HVAC doesn’t reach the converted space. The final building inspection and electrical inspection close out the permit. We walk the unit with you, run every fixture, test every outlet, and make a punch list if anything needs attention. Everything we do is covered by our 730-Day Done Right Promise: if it’s not done right, we make it right.
The options you’ll choose between
A junior ADU lives and dies by the decisions you make on the finishes and systems. Here’s what you’ll pick, with the straight trade-offs on each.
- Kitchenette depth: wet bar vs full cook station. A wet bar with a sink, undercounter fridge, and microwave keeps the permit simple and the cost lower. Adding a two-burner induction cooktop or a 24-inch electric range triggers ventilation requirements under Florida Building Code and adds a dedicated 40-amp circuit. If the unit will house a family member long-term, a cooktop is worth the extra electrical work.
- Bathroom configuration: 3-piece vs full bath. A shower, toilet, and 24-inch vanity fit in roughly 35 square feet. Adding a tub pushes you past 50 square feet and may require a larger water heater, depending on your existing tank size. For most junior ADUs in Fort Myers, a walk-in shower makes more sense on both footprint and resale value, especially for an in-law suite.
- Flooring: LVP vs tile. Luxury vinyl plank runs $3-$6 per square foot installed, handles Fort Myers humidity without warping, and installs in a day or two. Porcelain tile costs more and takes longer but handles wet areas better and, in post-Ian Fort Myers, buyers perceive tile as higher-end. We install both and will give you a side-by-side cost breakdown.
- Climate control: mini-split vs PTAC vs ducted tie-in. If your existing central system has enough capacity and the duct layout reaches the converted space without major rework, tying in is cheapest. Most conversions can’t do that without sacrificing air balance in the rest of the house, so a ductless mini-split is the go-to. It gives you independent temperature control and runs on its own circuit. Brand matters here: we spec units sized for Florida humidity loads, not just square footage.
- Separate entrance: door cut vs existing access. Code requires a private entrance for an ADU. If the converted space is on an exterior wall, we cut and frame a new door opening, install a pre-hung exterior door rated for Wind-Borne Debris Region, and flash it to Fort Myers wind-driven rain standards. If the space is interior with no exterior wall access, we work within the existing entry layout, which sometimes means reconfiguring a hallway. This single decision can swing the budget by $3,000-$7,000 depending on structural and stucco work.
What a junior ADU and interior conversion costs in Fort Myers
Our projects land between $45,000 and $130,000. The five variables that push a job toward the low or high end are square footage, plumbing scope, electrical capacity, finish level, and whether we’re cutting an exterior door opening. A straightforward 350-square-foot attached-garage conversion with an existing bathroom rough-in, a wet-bar kitchenette, LVP floors, and a mini-split might come in around $60,000. A 600-square-foot den conversion requiring a slab-cut for drains, a subpanel upgrade, a new exterior door, tile throughout, and a full bathroom with a walk-in shower lands in the $100,000-$130,000 range.
Every estimate we write is a fixed-price, line-item quote. No ranges that turn into surprises. Your estimate will show permit fees, demolition, framing, plumbing rough-in and trim, electrical rough-in and trim, insulation, drywall, paint, flooring, fixtures, and the HVAC solution. What it won’t show unless you ask us to include it: furniture, window treatments, and any work outside the ADU footprint. If your conversion is part of a full Home Additions & ADU in Fort Myers project, we bundle the estimate so you see the whole picture in one document. Call (844) 638-7249 for a free on-site estimate, and we’ll break down the numbers for your specific floor plan.
What Fort Myers homes specifically do to this job
Fort Myers was ground zero for Hurricane Ian’s Category 4 landfall in September 2022, and that event rewrote the rulebook on how interior conversions are permitted and built here. If your home sits in a FEMA AE or VE flood zone, which covers a large swath of the city, your finished floor elevation must clear Base Flood Elevation plus the required freeboard. For an attached-garage conversion in a post-Ian floodway parcel, that often means the slab itself is already too low to legally convert to habitable space without raising the floor, which triggers an entirely different scope and cost structure. We verify your flood zone and BFE during as-built assessment, before you spend a dollar on design.
The housing stock in Fort Myers is split between 1950s-1980s concrete block homes along corridors like McGregor Boulevard and newer post-2002 Florida Building Code construction in master-planned communities east of I-75. The older block homes are tanks structurally, but their electrical panels are almost always underpowered for an ADU load, and the interior walls we need to move are often tie-beam block that requires engineering and a beam pocket detail. The newer homes have the panel capacity and hurricane-strap framing but were built with builder-grade everything, so we’re regularly replacing hollow-core doors, upgrading from the cheapest possible baseboard, and adding sound insulation between the ADU and the main house that the original builder skipped.
After Ian, Lee County saw a wave of unlicensed out-of-state contractors who took deposits and disappeared or did non-compliant work, which prompted joint DBPR enforcement sweeps. Homeowners here have been burned in ways that homeowners in undamaged markets simply haven’t. We carry our Lee County license on every estimate and every permit application. No subcontractor roulette, no unmarked vans. Our Home Additions & ADU crew is background-checked and uniformed, and every job is covered by the 730-Day Done Right Promise: if something isn’t right, we fix it.
Serving Fort Myers, FL - Our Local Coverage Area
We’re based in the Fort Myers 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 - Junior ADU & Interior Conversion in Fort Myers
Most junior ADU and interior conversions in Fort Myers take 10 to 16 weeks from the day we start demolition. The biggest variable is the Lee County permit review timeline, which can add two to four weeks before we swing a hammer, especially if your property falls in a flood zone requiring elevation verification. Material lead times for custom cabinets and countertops can add another two weeks if you’re not selecting from in-stock lines. We’ll give you a week-by-week schedule at the estimate stage and update it as permits clear.
Yes. Converting any space into habitable square footage in Fort Myers requires a building permit, and if you’re adding plumbing or altering electrical, you’ll need separate mechanical, plumbing, and electrical permits. Lee County and the City of Fort Myers both require plans that show compliance with the Florida Building Code 8th Edition, including wind-load design, energy calculations, and floodplain management provisions if you’re in a Special Flood Hazard Area. We pull every permit for you and manage the inspections. Skipping permits on an ADU conversion is not a small risk: it voids your homeowners insurance on that square footage and kills resale value when the unpermitted work shows up on the seller’s disclosure.
It depends on where the existing plumbing is relative to the conversion space. If your attached garage shares a wall with a bathroom or laundry room, we can often tap into those drain and supply lines without cutting the slab. If the space is on the opposite side of the house, we’re cutting concrete to run drains, and that adds cost and time. Structural changes are avoidable if we’re working within the existing footprint and not removing load-bearing walls, but we won’t know that until we open the ceiling and check the joist direction and bearing points. We’ll tell you what’s possible during the as-built walkthrough before you commit to anything.
All-in pricing, including permits, materials, labor, and finishes, ranges from $45,000 for a smaller wet-bar conversion to $130,000 for a full-kitchen, full-bath unit with a separate entrance, tile floors, and a dedicated mini-split system. We offer 0% financing for 18 months and $1,000 off projects over $10,000, which makes a meaningful dent on a project of this scale. Every estimate is a fixed price, not a range that drifts upward mid-job. Call (844) 638-7249 and we’ll walk your space and give you a real number, not a guess.
In the post-Ian Fort Myers market, finished, permitted, code-compliant square footage is worth more than it was before the storm, in part because so much underpermitted work has come to light during rebuilds. A junior ADU with a separate entrance, its own bathroom, and a kitchenette typically appraises as additional living area and can return 60% to 80% of construction cost at resale, depending on the neighborhood. McGregor corridor historic homes, Gulf-access canal properties, and newer communities east of I-75 all support the investment. Some homeowners pair a junior ADU with a Kitchen Design & Layout in Fort Myers project at the same time, or use it as the first phase before tackling a Small & Partial Kitchen Remodel in Fort Myers elsewhere in the house. We serve the entire Fort Myers area and can talk through what makes sense for your specific street and comps.
Let’s walk your space and price it
A junior ADU and interior conversion in Fort Myers starts with a free on-site estimate. We’ll measure the space, check your panel, map the plumbing access points, verify your flood zone, and hand you a written, line-item quote. No pressure, no vague ranges, and no subcontractor unknowns. Our team answers calls live, 24/7, so you won’t sit in a voicemail queue when you have a question. Call (844) 638-7249 to schedule your walkthrough and lock in your quote.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Fort Myers home additions and ADU projects with fixed-price estimates and the 730-Day Done Right Promise.