What a Junior ADU & Interior Conversion in Lely Resort Actually Costs and How Long It Takes
A Junior ADU and interior conversion in Lely Resort typically falls between $45,000 and $130,000, with most projects we build landing in the $60,000 to $95,000 range. The job converts under-used interior space - a large bonus room, a portion of a garage that stays attached, or a ground-floor living area - into a self-contained accessory unit with its own entrance, bathroom, kitchenette, and sleeping area. In a concrete block stucco home here, where load-bearing walls aren’t always where you’d guess, the structural assessment alone shapes the budget from day one. Call (844) 638-7249 for a free on-site estimate that gives you a hard number, not a guess.
How a Junior ADU Conversion Comes Together Inside a Lely Resort Home
Most homeowners picture the finished space. We think about the first three days, because that’s where the real decisions live. Here’s the actual sequence we follow on a junior ADU and interior conversion in Lely Resort, start to finish.
Days 1-3: Existing-condition survey and ARB pre-check. We pull architectural drawings of your home if they exist - for Lely Resort’s CBS homes built between the mid-90s and 2010s, they often do. We map every load-bearing wall, chase, and plumbing stack that runs through the target space. Simultaneously, our team cross-references the scope against your neighborhood sub-association’s ARB requirements, especially if the conversion touches an exterior wall for a new private entrance door. The door’s profile and color must sit within the approved palette, and that door needs to be impact-rated to meet HVHZ code. You’ll make your first real choice here: where the new entrance lands and whether it’s a single door or a French-door configuration.
Days 4-10: Permitting and sub-association approval submission. A junior ADU requires a building permit from Collier County, plus electrical, plumbing, and mechanical sub-permits. In Lely Resort, we also submit to your community’s Architectural Review Board - a step that surprises homeowners who haven’t done a project here before. The ARB doesn’t just review rooflines and paint colors; they’ll look at any new exterior opening and the door style. The county reviews for structural, wind-load, and life-safety compliance. Both approvals run concurrently when we file, which saves two to four weeks versus sequential filing. You’ll decide on the kitchenette layout and fixture rough-in locations here, so the MEP plans are locked before we pull the permit.
Days 11-25: Interior demolition and rough-in. We open walls, cut the new entrance opening, and frame any partition walls. Plumbing rough-in for the bathroom and kitchenette runs first - in Lely Resort’s low-lying coastal plain, drain-line slope is critical because the wet-season water table sits high, and we often specify a backflow preventer on new gray-water connections even when code doesn’t require it. Electrical rough-in follows, with a dedicated sub-panel if the existing service can’t absorb the new load. This is the stage where a homeowner sees the space stripped back to studs and block, and it’s also where we discover anything the original builder hid - undersized headers, corroded rebar in older CBS sections, or electrical that was never permitted the first time.
Days 26-45: Close-up, finishes, and fixture install. Drywall, paint, flooring, tile, and trim. The bathroom waterproofing goes in per Florida Building Code - full-height membrane in the shower alcove, not just a pan liner. Kitchenette cabinets and countertops install next, then plumbing trim-out and light-fixture hang. You’ll walk the space with our project lead at rough-in and again at trim-out to confirm every switch, outlet, and fixture placement before we lock the drywall screws.
Days 46-55: Final inspections, punch list, and ARB sign-off. Collier County inspects structural, electrical, plumbing, and mechanical. Then we schedule the ARB final walk if the project triggered a review. We stay on-site through every inspection so you don’t have to coordinate with three different agencies. Once we have the signed finals, we walk the punch list with you. Any item not right gets fixed under the 730-Day Done Right Promise - no expiration clock games.
The Choices That Shape Your Junior ADU & Interior Conversion
Every project we price in Lely Resort comes down to a handful of decisions that move the number more than anything else. Here’s what you’ll choose between and what each path costs in practical terms.
- Entrance type: impact-rated single door vs. French-door pair. A code-compliant impact-rated single door with sidelight runs $3,500 to $6,000 installed with new-header framing. A French-door pair with the same wind rating adds $7,000 to $12,000, but it floods the unit with light and makes the space feel like a real apartment, not a converted back room. For homeowners planning to use the unit as rental income, the French door pays for itself in perceived value within the first lease cycle.
- Kitchenette configuration: wet bar vs. full compact kitchen. A wet bar with a sink, under-counter fridge, and microwave nook lands at $4,000 to $8,000 including plumbing rough-in. Adding a two-burner induction cooktop, a small dishwasher drawer, and proper range-hood ventilation pushes the kitchenette into $10,000 to $18,000 territory. The ventilation duct to the exterior is often the surprise cost driver - in a CBS home, coring a six-inch hole through exterior block with proper sealing and a code-rated termination cap isn’t a quick punch-out.
- Bathroom scope: half-bath vs. three-quarter with shower. A powder room (toilet and sink) keeps the plumbing scope tight and runs $5,000 to $10,000. A three-quarter bath with a tiled walk-in shower, glass enclosure, and floor-to-ceiling waterproofing lands at $12,000 to $22,000. In Lely Resort, where most junior ADUs are built for visiting family or seasonal tenants, the shower is almost never skipped - the unit loses its independence without it.
- Flooring: luxury vinyl plank vs. porcelain tile. LVP runs $4 to $8 per square foot installed and handles the humidity swings of a Collier County summer without buckling. Large-format porcelain tile runs $9 to $16 per square foot installed and stays cooler underfoot, but it requires a flatter substrate on a CBS slab, which sometimes means a self-leveling pour that adds $1,200 to $2,500 to the floor prep budget.
What Junior ADU & Interior Conversion Costs in Lely Resort, FL
We price most junior ADU and interior conversion projects in Lely Resort between $45,000 and $130,000. The spread is wide because no two homes in this community have the same floor plan, the same available square footage, or the same original build quality - a 1998 villa and a 2012 estate home in The Player’s Club present completely different starting points. Here’s what drives a project toward the low or high end of that range.
Square footage of the finished unit. A compact 250-square-foot studio conversion with a kitchenette and three-quarter bath stays in the $45,000 to $65,000 zone. A 500-square-foot one-bedroom layout with a full compact kitchen, separate bedroom wall, and larger bath pushes into the $85,000 to $130,000 range. Every added foot of plumbing drain line, every extra circuit, and every additional window or door opening adds cost in linear steps, not big jumps.
Existing plumbing and electrical proximity. If the target space sits directly above or adjacent to an existing bathroom group, the plumbing rough-in cost drops sharply - we’re tying into stacks and vents that are already there. If we need to run new drain lines across a slab or through CBS walls to reach the nearest stack, the plumbing scope can add $8,000 to $18,000 before we hang a single fixture.
Exterior wall penetration for the private entrance. Cutting a door opening through a reinforced CBS exterior wall requires engineered lintels and an impact-rated door assembly. On a wall that faces the prevailing storm-wind direction - east and southeast exposures in Lely Resort - the structural header requirements tighten further under HVHZ code. This single element ranges from $5,000 to $14,000 depending on wall location, door choice, and whether we need to relocate electrical conduit that runs through that section of block.
Interior-finish grade. Stock-grade cabinets, a fiberglass shower pan, and builder-grade LVP keep material costs low. Moving to plywood-box soft-close cabinets from a brand like KraftMaid, a tiled shower base with frameless glass, and stone or quartz countertops on the kitchenette adds $7,000 to $18,000 in materials. We show you line-item options with the real cost difference - no vague “upgrades” line on the quote. Every written estimate from us spells out exactly what’s included, from the door model to the paint sheen, so you’re comparing apples to apples.
What Lely Resort Homes Specifically Do to This Job
Lely Resort isn’t just another Naples subdivision - it’s a master-planned golf community with a binding Architectural Review Board that has approval authority over every exterior modification, including the new private entrance most junior ADU conversions require. Before we submit anything to Collier County, we confirm the door style, profile, and color with your neighborhood’s ARB using the current approved-products list. That list differs by sub-association - a door color permitted in GreenLinks may not be permitted in The Classics - and guessing wrong means a stop-work order and a re-order delay measured in weeks, not days. Contractors unfamiliar with the community’s layered approval structure learn this the hard way. We’ve been through the ARB submission process enough times to know which supporting documents they want, in which order, and how to keep the county permit and the ARB review running on parallel tracks so neither holds the other up.
The homes themselves, built as CBS block from the mid-1990s forward, handle interior conversions well structurally because the exterior shell is already wind-rated for HVHZ loads. But the block construction also means that any new opening through an exterior wall - the private entrance door - requires a concrete-cutting crew, an engineered lintel, and a water-intrusion seal detail specified for wind-driven rain at 140 mph. We core, frame, and flash that opening as if it’s going into a new-construction home on the coast, because in every way that matters, it is. The same goes for running new circuits: the 20-to-30-year-old panels in the community’s earlier-phase homes sometimes lack the spare capacity to absorb a junior ADU’s electrical load, and a sub-panel upgrade becomes part of the scope - one we flag during the first three days of survey work so it’s never a mid-project surprise.
For homeowners already planning a broader property upgrade, this conversion often pairs naturally with a Home Additions & ADU in Lely Resort scope, especially when the long-term plan includes a detached unit down the road. And because we’re already opening walls and running MEP rough-ins, some families use the same project window to update the adjacent kitchen - our Kitchen Design & Layout in Lely Resort and Small & Partial Kitchen Remodels in Lely Resort crews coordinate with the ADU team so the house isn’t torn up twice. Everything runs through our Home Additions & ADU division, so one project lead manages the whole job from ARB submission to final inspection.
Serving Lely Resort, FL - Our Local Coverage Area
We’re based in the Lely Resort 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 Lely Resort
Plan on 8 to 12 weeks from the day we start demolition to the day you’re walking the finished unit. The ARB review timeline can extend that by two to four weeks if the board meets on a monthly cycle and we miss a cutoff - we file as early as possible in the process to keep the approval window from stretching the schedule. A simple conversion with no exterior-door work often finishes in 7 weeks; a full-kitchen, full-bath conversion with a new wall penetration runs closer to 11 or 12 weeks once inspections are factored in. Call (844) 638-7249 and we’ll give you a schedule tied to your specific floor plan.
Yes. Every junior ADU conversion in Collier County requires a building permit with electrical, plumbing, and mechanical sub-permits. In Lely Resort specifically, any exterior modification - including the new private entrance most these projects add - also requires approval from your neighborhood’s Architectural Review Board. We handle both the county and ARB submissions as part of our scope, and we won’t cut a single block until both approvals are in hand. Unpermitted work on an accessory unit creates title issues when you sell and code-enforcement liability while you own it. Not worth the gamble.
Technically yes - the unit can share the home’s main entrance and still function as an accessory dwelling. But in practice, a junior ADU without its own private entrance loses the independence that makes it a real rental or guest suite. The door changes the use case from “spare room with a bathroom” to “standalone apartment.” If you’re avoiding the ARB review or the cost of cutting a block wall, we can phase the project: build the interior now with a framed-and-sheathed knockout panel where the door will go, and add the exterior door as a separate permit scope later.
Electrical service capacity. Many of the earlier-phase CBS homes in Lely Resort were built with 150-amp panels that are already near capacity with the home’s existing load. Adding a junior ADU - with its own kitchenette circuits, bathroom GFCI circuits, and dedicated HVAC mini-split - can push the demand past what the panel can safely carry. A sub-panel upgrade or a full service upgrade to 200 amps adds $2,500 to $5,500 to the project, and it’s not optional if the load calculation demands it. We catch this during the first three days of survey work, so you’ll know the number before we start, not after the walls are open.
Every junior ADU and interior conversion we build in Lely Resort is backed by our 730-Day Done Right Promise. If something isn’t right - a cabinet door that’s off-register, a shower valve that drips, a drywall seam that telegraphs - we come back and make it right, no fine-print expiration and no runaround. That coverage sits on top of the manufacturer warranties on every fixture, appliance, and finish material we install. Written line-item estimates, upfront pricing, and a warranty that actually means something - that’s how we’ve kept homeowners calling us back for over 42 years across our markets. For a free estimate on your junior ADU conversion, call (844) 638-7249.
Get a Hard Number on Your Junior ADU & Interior Conversion in Lely Resort
A real estimate starts with a real walkthrough. Call (844) 638-7249 and Derek Hollenbeck or a member of our Lely Resort project team will schedule an on-site visit, map your existing space, and give you a written, line-item price for the conversion - not a ballpark, not a range, and not a number that changes once the walls come open. We cover ARB submission, Collier County permitting, impact-rated door and window specs, and every rough-in, finish, and trim choice in that estimate. Free project estimate and design consult included. Calls answered by a live person, 24/7.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Lely Resort and the surrounding communities.