Trusted Home Additions & ADU for Fort Myers Homeowners
Adding square footage to your Fort Myers home, whether it’s a ground-floor room addition, a second story, or a fully permitted accessory dwelling unit, typically costs between $45,000 and $130,000 depending on scope, foundation work, and finish level. At Groundwork Construction Co., we handle the entire project from foundation to finish line: design, engineering, permitting through Lee County, and the build itself, so you don’t juggle multiple contractors. Derek Hollenbeck and our team have been delivering this kind of work across Southwest Florida for over 42 years, and we back every home addition and ADU with our 730-Day Done Right Promise, one of the longest workmanship guarantees in residential construction. If you’re weighing whether to expand or move, call us at (844) 638-7249 for a free estimate and design consult. A live person answers, 24/7.
What Our Home Additions & ADU Service Includes
Home additions and ADUs are not one-size-fits-all, and the right approach depends on your lot, your home’s existing footprint, and how you want to use the new space. Below are the specific build types we handle across Fort Myers, Lochmoor Waterway Estates, North Fort Myers, and the surrounding communities. Every project starts with the same commitment: upfront pricing, no surprises, and a written line-item quote before we move a single shovel of dirt.
ADU Design & Permitting
An ADU in Fort Myers needs to comply with Lee County zoning, FEMA flood elevation requirements, and the Florida Building Code. Our team handles the full ADU Design & Permitting package, including site surveys, architectural drawings, and structural engineering, so you’re not stuck at a counter downtown trying to decipher plan-review comments. Whether it’s an attached unit or a detached backyard cottage, we submit a permit-ready set that reflects exactly what gets built. The goal is a fast track through review with no re-submittal delays.
Garage Conversion ADU
A Garage Conversion ADU into a rentable studio or in-law suite often falls in the $30,000 to $80,000 range, and it’s one of the fastest paths to a livable ADU since the shell is already standing. We assess the slab, roof ties, and electrical service to determine what can stay and what needs upgrading to meet current code. In neighborhoods like Whiskey Creek or McGregor, where garages were built decades ago, we commonly replace the overhead door with a wall system that matches the main house, insulate to Energy Code, and run new plumbing for a kitchenette or full bath.
New Detached ADU
A ground-up detached ADU gives you complete control over floor plan, orientation, and privacy, and it’s the preferred choice on larger Fort Myers lots where the main house sits forward on the property. We excavate for a frost-protected slab or stem-wall foundation, frame the structure, tie into existing utilities, and handle the separate electrical meter if you plan to rent the unit. Material brands like James Hardie siding and Andersen windows come standard in our curated portfolio, so the ADU holds up to Florida humidity and looks like it belongs on the property, not an afterthought.
Junior ADU & Interior Conversion
A Junior ADU & Interior Conversion transforms underutilized interior square footage, like a oversized bonus room, a walk-out basement level, or a section of the main floor that can be walled off with its own entrance. These projects run smaller and faster than a full detached build, and they often don’t trigger the same setback or utility-impact fees. We handle the fire separation, sound attenuation between units, and the compact kitchen and bath rough-ins that make the space legally habitable. For Fort Myers homeowners who want a caregiver suite or adult-child apartment without adding new foundation, this is the most cost-effective path.
ADU Site Prep & Utilities
Before a single wall goes up, ADU Site Prep & Utilities work must clear, grade, and tie the site into water, sewer, and electric. In low-lying areas like Palmona Park or parts of Tice, we pay special attention to lot drainage and may bring in fill to get the finished floor elevation above the base flood elevation. Our in-house crews handle trenching, conduit, backflow prevention, and the new electrical panel, so you’re not coordinating separate subs. We pull all utility permits and schedule the inspections, keeping the job on a single timeline.
Room Additions
A ground-floor room addition, whether it’s a family room bump-out, a master suite expansion, or a dedicated home office, is often the answer when you love your neighborhood but have outgrown the original floor plan. We match rooflines, stucco texture, and interior trim so the new space doesn’t read as “added on.” In Cypress Lake and Villas, where mid-century ranches are common, we’ve done dozens of seamless rear additions that open onto a new paver patio, effectively doubling the living area without touching the front elevation. Every room addition is engineered for hurricane wind loads and comes with our 730-Day Done Right Promise.
Second Story Additions
Adding a second story is a major structural undertaking that requires an engineer’s analysis of the existing foundation and first-floor framing. We’re up front about what the existing footings can carry and whether we need to reinforce with new columns or shear walls. This route preserves yard space and is popular in Pine Manor and Suncoast Estates, where lot sizes run smaller. We protect the lower level with weather-tight temporary enclosures during framing, and we coordinate the stairwell integration so it feels original, not shoehorned.
Sunrooms & Enclosed Patios
A sunroom or enclosed patio gives you bug-free, climate-controlled square footage at a lower cost per foot than a full foundation addition, and in Fort Myers, that means year-round use without the mosquitoes and afternoon humidity. We use insulated low-E glazing, engineered roof ties, and concrete floor slabs that double as a thermal mass for passive cooling. Whether it’s a three-season room off the lanai or a fully conditioned Florida room tied into your central HVAC, we design it to the same wind-load standards as the rest of the house.
What happens when you call
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A real person answersNo phone trees - you reach a local pro.
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You get an upfront price rangeHonest numbers before anyone is dispatched.
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A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Brands We Use for Home Additions & ADU
We’ve built enough additions across Southwest Florida to know which material brands stand up to salt air, afternoon downpours, and 90-degree humidity without callbacks. Our window and door work relies heavily on Andersen and Pella products: we keep their impact-rated lines in regular rotation because the engineering is consistent and the coastal hardware packages don’t corrode after two summers. For exterior cladding, James Hardie fiber cement is our default on new ADUs and room additions; it handles the Fort Myers moisture cycle better than vinyl and takes paint cleanly. On hardscape tie-ins like new driveways, walkways, or patio extensions that often accompany an addition, we spec Belgard and Unilock pavers. Whether you have a specific brand preference or want our recommendation based on 42 years of watching which products hold up, we can guide you to the right materials without an upsell.
Signs You Need a Home Addition or ADU Right Now
- Your family has outgrown the bedroom count, and the Fort Myers market is too expensive to move. When the cost of selling, buying, and paying today’s mortgage rates pencils out higher than a room addition or ADU, expanding your current home is often the smarter financial move. We can run a preliminary budget in the first meeting so you can compare real numbers, not guesses.
- You’re caring for an aging parent and need a separate, ground-level living space. A junior ADU or garage conversion puts family close by but not on top of each other, with its own entrance and kitchenette. In neighborhoods like McGregor where lots are established, this arrangement keeps generations together without sacrificing privacy.
- You’re leaving rental income on the table while demand spikes for Fort Myers winter housing. A detached ADU or over-garage apartment can generate $1,500 to $2,500 a month in seasonal rent in this market. If your lot and zoning allow it, the numbers often support the build cost within a few years.
- Your current floor plan doesn’t work for remote work, and you’re crammed into a spare bedroom. A dedicated home office addition with its own entrance, sound insulation, and separate HVAC zone pays for itself in productivity and sanity. We build these as conditioned, permitted extensions, not converted closets.
- You love your neighborhood and schools but feel the house itself is holding you back. Cypress Lake, Whiskey Creek, and Villas have mature trees and established neighbors you can’t replicate in a new subdivision. A well-designed addition keeps the location and gives you the square footage you’d otherwise chase in a move.
Our Home Additions & ADU Process, Step by Step
We run every home addition and ADU project through the same disciplined sequence, refined over more than four decades of building in Lee County. The process is built around upfront pricing and a single point of contact, so you always know who to call.
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Free on-site estimate and design consult. Derek or a senior project lead walks your property with you, takes measurements, checks the existing electrical panel capacity and foundation condition, and listens to how you want the new space to function. You leave that first meeting with a rough budget range and a clear sense of what’s feasible under local code.
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Design, engineering, and permitting. Our in-house drafter and structural engineer produce the permit set: floor plans, elevations, wind-load calculations, and energy compliance forms. We submit to Lee County and track the plan review, resolving any comments directly so your permit isn’t stalled in a backlog.
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Material selection and contract. You choose finishes from our curated portfolio of brands like KraftMaid for cabinetry, Kohler for fixtures, and Belgard for exterior hardscape. We provide a fixed-price contract with a line-item breakdown and a build schedule. No allowances that balloon later, no change-order surprises.
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Build and site management. Our background-checked, uniformed crew handles demolition, foundation, framing, rough-ins, drywall, flooring, trim, and punch-out. We protect the existing living space with dust partitions and keep the site broom-clean at the end of each day. A dedicated project manager is on-site or available by phone daily.
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Final walkthrough and 730-Day Done Right Promise activation. We walk the space together, test every outlet and fixture, and confirm the HVAC balance. Your 730-Day Done Right Promise starts the day we hand you the keys: if it’s not done right, we make it right, for two full years, no fine print.
How Much Does a Home Addition or ADU Cost in Fort Myers?
A room addition in Fort Myers typically runs $45,000 to $130,000. A ground-up detached ADU generally lands between $90,000 and $220,000, and a garage conversion falls in the $30,000 to $80,000 range. These numbers shift with square footage, site conditions, finish level, and whether you need a separate electrical meter or upgraded septic capacity. Here’s a breakdown by project type so you can model your budget:
- Ground-floor room addition: $45,000 - $130,000
- Second story addition: $90,000 - $220,000
- New detached ADU: $90,000 - $220,000
- Garage conversion ADU: $30,000 - $80,000
- Junior ADU / interior conversion: $25,000 - $70,000
- Sunroom or enclosed patio: $35,000 - $80,000
What drives the final price? Foundation type and soil conditions matter: a stem-wall foundation on a well-draining McGregor lot is a different cost than a slab on fill in a lower-lying area. Utility tie-ins, impact-rated windows, and the finish package (trim level, flooring, countertops) are the main levers you control. We keep the price locked once the contract is signed. We also offer 0% financing for 18 months and $1,000 off projects over $10,000, which makes a large-scale addition more accessible without compromising on materials or craftsmanship. Call (844) 638-7249 to schedule a free estimate and get a written, line-item price for your specific project. The number you see is the number you pay.
Home Additions & ADU Near Fort Myers, Our Service Area
We build Home Additions & ADU in Fort Myers and across the broader Southwest Florida region, including Lochmoor Waterway Estates, Home Additions & ADU in North Fort Myers, Pine Manor, Whiskey Creek, Villas, Palmona Park, McGregor, Tice, Cypress Lake, Cape Coral, and Suncoast Estates. Most of our projects are within a 30-minute drive of our Fort Myers base, and our crews are on-site daily until the job is done. If you’re just outside these areas, call us anyway: we frequently take on custom builds in neighboring communities.
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 Questions, Home Additions & ADU in Fort Myers
A home addition expands the main dwelling’s living space and is accessed from inside the existing house, while an ADU is a separate, self-contained living unit with its own entrance, kitchen, and bathroom. ADUs in Fort Myers can be detached new builds, garage conversions, or interior conversions, and they often require their own utility connections and a separate address. Both add value and square footage, but the permitting path and cost structure differ enough that we walk you through both options during the estimate.
A typical room addition runs 8 to 16 weeks from permit issuance to final walkthrough. A detached ADU or second-story addition usually takes 4 to 6 months, with the biggest variable being Lee County plan review times and weather days during the wet season. We build a realistic schedule into the contract and give you weekly updates, so you’re never guessing when the drywall will be up. Call (844) 638-7249 for a timeline specific to your project.
An ADU in Fort Myers ranges from $90,000 to $220,000 for a new detached build, and $30,000 to $80,000 for a garage conversion. The range depends on square footage, foundation type, utility work, and the finish level you choose. Our estimates are line-itemed and fixed, so you’ll see exactly where the dollars go before you sign anything.
We pull all permits. The building permit, electrical, plumbing, mechanical, and any right-of-way or impact-fee paperwork are handled by our team as part of the project. You don’t set foot in the Lee County permitting office. We also schedule and attend every inspection, from footing to final, and we don’t collect the final payment until the job passes.
The price won’t change unless you change the scope. Our contract is fixed-price with a detailed scope of work attached, so you know what’s included. If you decide mid-project to upgrade countertops or add a bathroom, we price that as a separate, signed change order. There are no hidden allowances that balloon halfway through. If it’s not in the contract, you don’t pay for it.
Every addition and ADU we build is covered by our 730-Day Done Right Promise, one of the longest workmanship guarantees in residential construction. If something isn’t done right two years after the project is finished, we make it right. Manufacturer warranties on windows, roofing, siding, and appliances run alongside our workmanship coverage, and we handle the claim process for you.
Yes. We serve all of Lee County, including Home Additions & ADU in Lochmoor Waterway Estates, Cape Coral, North Fort Myers, and the surrounding communities. Our crews are local and on-site daily, and we know the local code amendments and flood-zone requirements in each municipality. Call us at (844) 638-7249 to check availability in your specific neighborhood.
Schedule Your Home Addition or ADU Estimate in Fort Myers Today
You don’t need to move to get the space your family needs. Whether it’s a sunroom off the back, a full second story, or a rental-ready ADU in the backyard, Groundwork Construction Co. delivers built-to-last results backed by our 730-Day Done Right Promise. Call (844) 638-7249 to schedule your free, no-obligation estimate. A live person answers, 24/7, and the quote you get is the number you pay. From foundation to finish line, we’re the partner who shows up and gets it done right.
Written by Derek Hollenbeck, Owner at Groundwork Construction Co., serving Fort Myers and Lee County since 2014.