What a Junior ADU & Interior Conversion Costs and Takes in Lehigh Acres, FL
A Junior ADU and interior conversion in Lehigh Acres typically runs $45,000 to $130,000, depending on whether you’re carving living space out of an existing footprint, bumping out a wall, or adding a compact new structure. Most jobs take 12 to 18 weeks from permit pull to final walkthrough, with the interior conversion portions moving faster than any foundation or utility work. Call (844) 638-7249 if you want a written, line-item estimate that breaks down exactly where your number lands: no vague ranges, no change-order surprises later.
Lehigh Acres sits on flat pine flatwoods with a high seasonal water table, so any job that touches the slab, adds square footage, or re-routes plumbing demands careful attention to drainage and foundation stability upfront. That reality shapes every junior ADU project we take on here, and it’s why our process starts with what’s under the house before we ever talk about finishes.
How We Build a Junior ADU or Convert Existing Interior Space
The sequence matters because skipping steps, especially in Lehigh Acres, is what turns a clean estimate into a mess. Here’s how we move, stage by stage:
1. Site and existing-condition assessment (days 1-3)
We walk the property with you and look hard at the existing slab, roof structure, electrical panel capacity, and plumbing stub locations. On legacy lots in Lehigh Acres, some platted in the 1950s and never built on, we also verify utility availability and access with Lee County Public Works before engineering anything. You’ll decide, with our input, whether the project stays entirely inside the existing footprint or includes a small bump-out. That single decision swings the budget more than any material choice later.
2. Plans, engineering, and permit submission (weeks 1-4)
We produce the architectural drawings, coordinate the structural engineering, and submit to Lee County. The flat, high-water-table conditions here mean stormwater management and slab engineering get scrutinized, so we front-load that work. You approve the floor plan, the fixture locations, and the finish schedule before we submit. Permitting turnaround in Lehigh Acres varies, but four weeks is a safe planning number for most junior ADU projects.
3. Demo, subfloor, and rough-in (weeks 4-8)
If we’re converting a garage or underutilized interior space, we strip it to the studs, address any moisture intrusion from the high seasonal water table, and lay down new subfloor where needed. Plumbing rough-in, electrical rough-in, and any HVAC ducting go in. This is the stage where we discover what’s actually behind the drywall on 1960s CBS homes and early-2000s tract builds, the two housing stocks that dominate Lehigh Acres. We quote with contingency for what we expect to find based on the build era, but we walk you through anything unexpected in real time.
4. Drywall, trim, and finishes (weeks 8-14)
Insulation, drywall, tape, texture, paint, flooring, baseboards, door casing, interior doors. For a junior ADU, this stage also includes the kitchenette or wet-bar rough-in if that’s in the plan, along with bathroom tile, vanity set, and shower or tub surround. This is where the choices you made in stage two become real. We protect the rest of the house with floor-to-ceiling zip walls so you’re not living in a dust cloud while we work.
5. Fixtures, trim-out, and final inspection (weeks 14-18)
Lighting, plumbing fixtures, appliance hookups, hardware, paint touch-ups, and a full clean. We schedule the final Lee County inspection, walk the job with you, and don’t consider it done until you sign off. Every junior ADU and interior conversion we complete carries our 730-Day Done Right Promise: if something isn’t right, we make it right, no argument, no delay.
Throughout this process, you’re also talking with our Home Additions & ADU in Lehigh Acres team about any broader scope that might make sense while the walls are open. That conversation happens early, not as a surprise add-on later.
The Options You’ll Choose Between
Every junior ADU and interior conversion involves a handful of fork-in-the-road decisions. These are the ones that matter most:
- Inside the existing footprint versus a small addition. Converting a garage or underused room keeps costs on the lower end, often in the $45,000-$70,000 range. Adding even 200 square feet of conditioned space pushes the number toward $90,000-$130,000 because you’re into foundation work, roof tying, and exterior siding matching.
- Plumbing scope. A junior ADU with a full bath and kitchenette that ties into existing drain lines costs less than one that requires a new sewer lateral or a grinder pump because the slab elevation is too low. On the flat Lehigh Acres lots, slab elevation and drain slope are constant constraints.
- Electrical panel capacity. If your existing panel has open breaker slots and enough amperage to carry a mini-split, electric water heater, and kitchen circuits, you save several thousand dollars. If we need a sub-panel or a service upgrade, that adds real cost we’ll flag in the estimate.
- Finish level. Standard LVP flooring, off-the-shelf cabinets, and a fiberglass shower surround keep costs lean. Engineered hardwood, custom cabinetry, quartz counters, and tile showers move toward the high end. We source from partners like Quikrete and Sakrete for concrete and underlayment work, and we spec finishes that hold up in Florida’s humidity, not just what photographs well.
- Separate entrance and kitchen definition. A true junior ADU needs its own exterior access and a defined kitchen space, per Lee County code. Interior conversions that feel like an extension of the main house, without a locking door and cooking facilities, are simpler and less expensive. We walk you through the code requirements for each path so you know what you’re getting permitted for.
What Junior ADU & Interior Conversion Costs in Lehigh Acres, FL
We price these jobs between $45,000 and $130,000. Where you land depends on four things: whether you’re staying inside the existing walls or adding square footage, whether you’re moving plumbing lines or dropping new ones, the finish grade you choose, and what the pre-drywall inspection reveals about the existing structure.
A written estimate from us includes the architectural plans, structural engineering, permit fees, all labor and materials, rough and finish plumbing and electrical, drywall, paint, flooring, trim, fixtures, and a final clean. It also includes a line for what we call “known-unknowns”: the things we expect to find based on the build era of your home. The 1960s CBS homes in Lehigh Acres often hide corroded cast-iron drain lines and undersized wiring. The 2003-2008 boom-era tract homes frequently have slab settling and cheap original windows. We budget for these upfront because we’ve seen them hundreds of times.
What does not sit inside a standard junior ADU estimate: custom millwork beyond basic trim, high-end appliance packages, structural repair to existing framing not related to the conversion, and any unpermitted prior work that needs to be brought to code before we can proceed. If those come up, you’ll know the dollar figure before we pick up a hammer.
If you’re considering pairing this with other work, some homeowners in Lehigh Acres start with the ADU and then roll into a Small & Partial Kitchen Remodels in Lehigh Acres project in the main house, or a Kitchen Design & Layout in Lehigh Acres reconfiguration. We can sequence the work so you’re not dealing with two separate contractors and two separate schedules.
What Lehigh Acres Homes Specifically Do to This Job
Lehigh Acres was mass-platted in the 1950s and 60s, with tens of thousands of lots carved out of pine flatwoods, many of which sat vacant for decades. When we pull permits for a junior ADU on one of these legacy lots, we frequently run into absent utility hookups, poor natural drainage, and platted roads that exist only on paper as overgrown dirt tracks. Pre-permit coordination with Lee County Public Works on access and utility stub locations is not optional here; it’s the first phone call we make. The post-Hurricane Ian reconstruction surge layered additional complexity on top of that: Ian’s Category 4 inland winds tore through roofs, trusses, and screen enclosures across Lehigh Acres, and we still find hidden wind damage inside wall cavities and attic spaces on homes that looked fine from the street.
The housing stock itself splits into two distinct realities. The original 1960s-70s concrete block homes, built small for the retirement market, often have corroded cast-iron drain lines, flat or low-slope roofs with decades of patchwork, and electrical systems never designed for modern loads. The 2003-2008 tract CBS homes, built during the speculative boom and then battered by foreclosures, carry years of deferred maintenance, slab settling from the high water table, and builder-grade everything. A single Lehigh Acres street can yield a full gut-renovation on a 1965 original right next to a warranty-era repair job on a 2006 build. Our junior ADU estimates account for which era we’re walking into because the scope is never the same.
The flat terrain and seasonal ponding are constants. Every project we design factors in site grading, engineered fill where needed, and stormwater management. These are not line items you can skip, and they’re not priced into a generic “ADU cost per square foot” number you’ll find online. Our Home Additions & ADU crew knows Lee County’s drainage requirements cold, and we build them into the bid from day one so you’re not financing a surprise retention swale later.
Serving Lehigh Acres, FL - Our Local Coverage Area
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Frequently Asked - Junior ADU & Interior Conversion in Lehigh Acres
Plan on 12 to 18 weeks. The permitting phase alone can take four weeks in Lehigh Acres, and the construction phase runs 8 to 14 weeks depending on whether foundation work, new plumbing, or structural modifications are involved. A simple garage conversion with no added square footage and no relocated plumbing finishes on the shorter end. Call (844) 638-7249 for a timeline mapped to your specific scope.
Yes. Lee County requires building permits for any interior conversion that adds a dwelling unit, alters the building envelope, relocates plumbing or electrical, or changes the use of a space. A junior ADU that creates a separate living area with its own entrance, kitchen facilities, and bathroom triggers all of the above. We handle the plans, engineering, and permit submission as part of the project, and we don’t start work until the permit is in hand.
Sometimes. If the space you’re converting, like a large garage or a ground-floor bonus room, sits adjacent to existing plumbing walls and doesn’t require cutting into the slab, we can often tie into the existing drain and supply lines. That keeps costs toward the lower end of the $45,000-$130,000 range. But many Lehigh Acres homes, especially the older CBS stock, have slab-on-grade construction with plumbing buried in the floor. In those cases, adding a bathroom or kitchenette means cutting concrete, and we budget for it honestly in the estimate.
Architectural drawings, structural engineering, permit fees, all labor and materials, rough and finish plumbing, rough and finish electrical, drywall, insulation, paint, flooring, trim, doors, fixtures, hardware, and a project-specific contingency line for the conditions we expect to find based on your home’s build era. We also include protection of the rest of the house during construction. The estimate is upfront pricing, no surprises, and it comes from Derek Hollenbeck, who leads our estimating and project planning with a builder’s eye, not a sales pitch.
Every junior ADU and interior conversion we complete is covered by our 730-Day Done Right Promise: if it’s not done right, we make it right, for two full years. That covers workmanship across every trade. Material and product warranties run separately through the manufacturers we spec, like Oldcastle and Quikrete for concrete and masonry work, and carry their own timelines we’ll document for you at closeout. The promise is unconditional and in writing. No fine print, no excuses.
Get a Written Estimate for Your Junior ADU in Lehigh Acres
Call (844) 638-7249 to schedule a free on-site estimate for a junior ADU and interior conversion in Lehigh Acres. Derek Hollenbeck or a senior project lead will walk the property with you, discuss what’s possible inside your existing footprint, and deliver a written, line-item price that covers everything from permits to paint. Calls are answered by a live person, 24/7, and the estimate costs you nothing. If the numbers work, we’ll map out a start date. If they don’t, you’ll have a real plan and real pricing to compare.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Lehigh Acres and the surrounding communities with upfront pricing and the 730-Day Done Right Promise.