What a junior ADU and interior conversion actually costs and takes in Alva, FL
A junior ADU and interior conversion in Alva typically runs $45,000 to $130,000, with most projects finishing in 10 to 16 weeks. That range covers converting an attached garage, a large bonus room, or an underused interior footprint into a self-contained living space with its own entrance, kitchenette, bathroom, and sleeping area. Call (844) 638-7249 to schedule a free on-site estimate and we will give you a written line-item price before any work starts.
How a junior ADU conversion comes together, stage by stage
Every interior conversion in Alva follows the same five-stage sequence, but the timelines shift depending on whether we are adding a kitchenette, moving plumbing, or tying into existing systems. Here is what to expect.
Stage 1: Site walk and scope lock (Week 1)
We come out, measure the existing space, and map exactly where walls, doors, plumbing, and electrical will land. If your Alva property is in a post-Ian flood zone, we also check the finished floor elevation against the current FEMA AE/X requirements for attached living spaces. You decide the layout, the finish level, and whether the kitchenette gets a full range or just a cooktop and microwave. This stage takes about a week and ends with a fixed-price contract, not a ballpark.
Stage 2: Permitting and engineered drawings (Weeks 1-3)
Lee County requires permits for any interior conversion that adds a kitchen or bathroom, and the plans must show load paths, egress windows, and fire separation from the primary dwelling. We handle the drawings, the structural calcs, and the submittal. Plan check in Alva takes two to three weeks on average, though a flood-zone property may take an extra week if the elevation certificate needs updating. This is also when you pick your flooring, cabinet style, countertop material, and bathroom tile.
Stage 3: Rough-in and core systems (Weeks 3-7)
Once the permit is in hand, we open walls, run new circuits back to the panel, rough in the bathroom plumbing, and frame any interior partition walls. If the space was a garage, we replace the vehicle door with an insulated wall and a code-compliant entry door. This is the loudest, dustiest phase, but also the most important, because the plumbing drain slope, the electrical load calc, and the insulation R-value all get inspected before we close anything up.
Stage 4: Close-up and finish surfaces (Weeks 7-12)
Drywall goes up, gets taped and textured, then we install the kitchenette cabinets, the bathroom vanity, the shower or tub surround, and the flooring. Paint and trim come last. If you chose quartz countertops, the fabricator templates and installs during this window. We pressure-test the water lines and run the HVAC through a full cycle before final inspection. Most of what you will see and touch happens in these four weeks.
Stage 5: Final inspection and sign-off (Week 12-16)
The county inspector checks the electrical panel, the GFCI outlets in the bathroom and kitchenette, the smoke and CO alarms, the egress window, and the plumbing. We walk the space with you, test every switch and fixture, and hand over a close-out binder with the permit sign-off, appliance manuals, and the warranty paperwork. The 730-Day Done Right Promise starts the day you sign the completion form.
The materials and spec choices that shape your junior ADU
An interior conversion is not a one-size-fits-all box. The decisions you make in the first two weeks set the price, the timeline, and how the space holds up long-term. Here are the biggest ones.
- Kitchenette configuration. A wet bar with a sink, under-counter fridge, and microwave runs toward the lower end of the budget. Adding a two-burner electric cooktop, a dishwasher, and full-height cabinetry pushes the electrical and plumbing rough-in cost up, but makes the unit fully independent. Most Alva homeowners choose the full kitchenette path because it future-proofs the space for a long-term tenant or aging parent.
- Bathroom finish level. A fiberglass shower pan and acrylic surround with a stock vanity costs less and installs in two days. A tiled shower floor and walls with a glass door and a custom vanity takes longer but wears better in Florida humidity. We use moisture-resistant backer board on every shower, regardless of finish.
- Flooring across the unit. Luxury vinyl plank handles Alva’s humidity and occasional damp-floor conditions better than laminate or engineered wood. Tile costs more but is practically indestructible. Carpet belongs in bedrooms only and we do not recommend it in any room that opens to the outside.
- Wall and ceiling insulation. Converting a garage or bonus room means bringing the thermal envelope up to code. Spray foam on the underside of the roof deck works best in unconditioned spaces and cuts the cooling load noticeably. Batt insulation in the walls meets code at a lower material cost.
- Entry door and window specs. The new exterior door needs to be impact-rated or protected by a code-approved shutter system. If the conversion adds a bedroom, the egress window must meet Lee County’s minimum opening size and sill height. We spec Andersen or Pella for the door and window package on most Alva conversions.
What a junior ADU and interior conversion costs in Alva, FL
The $45,000 to $130,000 window covers real jobs we have priced in Alva. A straight garage conversion with a bathroom and a basic kitchenette, using existing electrical service and no major plumbing relocations, lands around $55,000. A full interior reconfiguration that moves drain lines, upgrades the panel, adds sound-rated partition walls, and finishes the space with quartz counters, tile floors, and custom cabinets pushes into the $110,000 range.
Here is what moves the number.
Plumbing distance. The farther the new bathroom and kitchenette are from the existing main stack, the more concrete gets cut and the more drain line gets run. In slab-on-grade homes, which are common in Alva, every added foot of trenching adds cost.
Electrical capacity. If your existing panel has open breaker slots and enough amperage to carry a mini-split, an electric water heater, and the kitchenette appliances, we avoid a service upgrade. If not, a new 200-amp panel and possibly a meter relocation add several thousand dollars to the job.
Floor elevation and flood zone. Homes in the Caloosahatchee floodplain sometimes require the finished floor of a habitable space to sit above the base flood elevation. If the existing slab is too low, we may need to build up the floor assembly, which changes door thresholds, stair details, and ceiling height.
Permit scope. A simple alteration permit costs less than one that triggers a floodplain review or requires a new elevation certificate. We include permit costs in your estimate line by line, so you see exactly what you are paying for.
Finish material grade. Stock cabinets, laminate counters, and vinyl flooring keep the budget lean. Semi-custom cabinets, quartz counters, porcelain tile, and solid-core doors raise it. Every written estimate from us shows the cost difference between the standard and upgraded choice so you decide with your eyes open.
What Alva homes specifically do to this job
Alva sits along the Caloosahatchee River in eastern Lee County, and the housing stock here is not the same as what you find in Fort Myers or Lehigh Acres. We work on older ranch homes built at grade, manufactured homes on agricultural parcels, and a growing number of post-Ian rebuilds that are elevated on stem walls or piers. That variety means every interior conversion starts with a different set of foundation and floor-elevation realities.
Since Hurricane Ian’s river flooding in 2022, many Alva parcels have been reclassified under updated FEMA flood maps. A garage or bonus room that was once a straightforward conversion may now require the finished floor to be two to four feet above the original slab. We frequently see this on properties near North River Road and the older subdivisions off Broadway. The fix is not complicated, but it does add framing, insulation, and flooring steps that an inland Lee County conversion would skip. We also deal with the reality that many Alva homes were built before current energy codes, so the wall cavities and attic spaces often need air sealing and insulation upgrades that a newer home would not. Our Home Additions & ADU in Alva team handles these elevation and envelope issues as part of the base scope, not as a change order.
Serving Alva, FL - Our Local Coverage Area
We’re based in the Alva 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 Alva
Ten to sixteen weeks is the realistic window for a permitted interior conversion. The biggest variable is the Lee County plan check timeline, which runs three to four weeks for a project that adds plumbing and a kitchen. Flood-zone reviews can add a week. We lock the schedule at contract signing and update you weekly so you always know which crew is on site and what gets done that week.
Yes. Lee County requires a building permit for any interior conversion that adds a bathroom, a kitchen, or a sleeping room. The permit package includes structural drawings, an electrical layout, a plumbing plan, and a mechanical plan for the HVAC. We pull the permit, manage the inspections, and hand you the signed final approval card at close-out. Skipping the permit risks a code enforcement lien and makes the space uninsurable as a dwelling unit. Call (844) 638-7249 for a free estimate that includes the full permit scope.
Sometimes. If the bathroom and kitchenette can sit against a wall that shares the main stack, we can tie in without trenching the slab. If the plumbing has to cross the floor, we cut the concrete and run new drain lines. We map both options during the site walk so you see the cost difference before you commit. Most Alva homeowners choose the layout that works best long-term, even when it means a little more slab work up front.
The per-square-foot cost in Alva typically lands between $180 and $280, depending on how much plumbing and electrical work the space needs. A 400-square-foot garage conversion with a basic bathroom and kitchenette runs roughly $55,000 to $75,000. A larger interior footprint with high-end finishes and a separate HVAC zone pushes toward the top of the $45,000 to $130,000 range. These numbers include permits, materials, labor, and finish work. Our written estimates break out every line item so you see exactly where the money goes.
Every junior ADU and interior conversion we build in Alva is covered by the 730-Day Done Right Promise. If something is not right, we make it right for two full years from the completion date. That covers workmanship across every trade, from the electrical rough-in to the final paint. Material defects are handled through the manufacturer warranty, and we manage those claims on your behalf. This is the same guarantee we put behind every Kitchen Design & Layout in Alva project and it means exactly what it says.
Your next move on a junior ADU in Alva
Start with a free on-site estimate. We walk the space, measure everything, talk through the layout options, and hand you a written line-item price, not a rough number that drifts later. That estimate includes the permit scope, the material specs, the timeline, and the total. Call (844) 638-7249 to schedule yours. A live person answers, day or night, and we can usually get to your Alva property within a few days. If your conversion is part of a larger Home Additions & ADU project or paired with Small & Partial Kitchen Remodels in Alva, we will bundle the scope so you deal with one contractor and one schedule. From foundation to finish line, we build it to last and back it in writing.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Alva and the surrounding Lee County communities.