Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Fast, Reliable Home Additions & ADU Across Lakehills
Home additions and ADU construction in Lakehills typically runs $45,000 to $130,000 for a room addition, $90,000 to $220,000 for a new detached ADU, and $30,000 to $80,000 for a garage conversion. Most projects near Medina Lake spend 4 to 8 weeks in permitting before the first footing gets poured, because the shoreline lots here carry overlapping FEMA floodplain rules and GBRA easement restrictions that flatland builders never deal with. Tom Barrett and his sons have been pulling Bandera County permits since 1998, and we know exactly what the county wants to see before you spend a dollar on materials. Call (877) 610-1318 for a free, line-item estimate on your Lakehills project.
Why Barrett & Sons Construction Is Lakehills’s Preferred Home Additions & ADU Company
We’re not a franchise dispatching strangers from three counties away. Tom Barrett lives close enough to be at your Lakehills jobsite the same week you call, and his sons run the crews that do the actual framing, concrete, and finish work. When we quote a room addition or ADU in Lakehills, the price you see is the price you sign, and every change after that arrives as a written change order before any work happens. No surprise invoices at the end, no “allowance” games.
Lakehills homeowners have a right to know who’s on their property. Every crew member who carries the Barrett & Sons name has passed a background check and arrives in uniform. Our 90-Day Done Right Promise is written on every contract: if something isn’t done right, one call brings Tom back to make it right. We also publish Tom’s name, address, and license number, so you can look us up before you sign anything. Ask anyone on your street, or call the county yourself.
We’ve seen what happens when an out-of-county contractor quotes a Lakehills ADU without understanding the shoreline rules. The homeowner pays for plans, starts construction, and then the GBRA easement letter arrives. That’s a tear-out waiting to happen. Our team pulls every permit, signs off every inspection, and runs the dual-regulatory checklist before we even order lumber.
Our Home Additions & ADU Services in Lakehills
ADU Design & Permitting
If your Lakehills property sits within 200 feet of Medina Lake, your ADU design starts with two questions: Where is the base flood elevation, and where does the GBRA shoreline easement line fall? We handle both at the same time. Our design process maps your flood zone, your setback, and your finish-floor elevation before we draft a single wall. That’s the difference between a permit that clears in weeks and one that bounces back twice because the county and the river authority don’t agree.

New Detached ADU
A new detached ADU on a Lakehills lot usually runs $90,000 to $220,000, depending on square footage, foundation type, and site access. Most lots have Edwards Plateau limestone just inches under the grass, which means hydraulic rock-breaking equipment for the footing trenches and utility runs. We factor that into the initial bid, not a change order later. On Wharton’s Dock Road, we cut into solid limestone for a 24-inch footing on a sunroom addition and the owner never saw a surprise bill for the rock work. That’s how it should work.

Garage Conversion ADU
Converting a garage in Lakehills costs $30,000 to $80,000 and is often the fastest path to rental income or a mother-in-law suite. But the older 1950s to 1970s fishing-camp garages in this area were never built as living space. Most lack proper foundation drainage, insulation, and code-compliant framing. We reframe, re-level, and pull the permitted electrical and plumbing rough-in so the finished ADU passes inspection the first time.

Junior ADU & Interior Conversion
A junior ADU carved out of an existing home is a smart option when a detached unit won’t fit inside the shoreline setback. We’ve done interior conversions in Lakehills homes where the finished floor elevation and easement line made a backyard ADU impossible. The trick is separating utilities cleanly, adding a code-compliant egress, and making the space feel like its own home, not a bedroom with a microwave.

What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
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You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Lakehills
We install materials you can look up, not mystery brands off a van. For Lakehills ADU windows and exterior doors, we regularly specify Simonton, Ply Gem, and PGT impact-rated lines, because Medina Lake storms don’t ask permission before they hit. PGT and CGI impact windows hold up to wind-driven debris and meet the coastal and lakefront building codes that apply to exposed shoreline lots. We keep these brands on hand for Lakehills customers and can order exact sizes without a six-week runaround.
Common Home Additions & ADU Problems We See in Lakehills Homes
- The dual-regulatory trap. A homeowner converts a garage into an ADU, passes the interior inspection, and then gets a GBRA letter saying the structure sits inside the shoreline easement. The wall has to come down. We check the easement line before we draw the plans, not after the drywall is hung.
- Limestone sticker shock. A room addition gets a flat $45,000 bid from an out-of-town builder, then the footing trench hits solid rock a foot down. The change order lands: $15,000 for rock breaking. We include excavation reality in the first quote, because in Bandera County, rock is the default, not the exception.
- Builder-warranty voids in newer developments. In master-planned Lakehills communities, HOA architectural rules require signed-off plans before rough-in. Cut into structural framing or alter the roof line without a permit and you void the builder warranty on the whole section of the house. We pull permits and file architectural submissions before the first nail.
- Fishing-camp foundations. Many of the old seasonal cabins around Lakehills were never built to full-time residential code. No engineered foundation, no proper drainage, and framing that won’t pass today’s inspection. Adding a room to one of these means fixing what’s underneath it first, or the new space inherits the same problems.
Pricing for Home Additions & ADU in Lakehills, TX
Here’s what a Lakehills homeowner can expect to pay for the most common Home Additions & ADU work in this market:
| Project | Typical Lakehills Range |
|---|---|
| Room Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion ADU | $30,000 - $80,000 |
Your final number moves on three things: square footage, foundation depth into limestone, and whether your lot sits inside a FEMA Special Flood Hazard Area. A lakefront ADU with elevated finished floors costs more than an interior conversion up the hill. We give you a written, line-item estimate before you commit, and our Home Additions & ADU team will walk you through every line. Call (877) 610-1318 to schedule your free estimate, and remember we offer a Free Second Opinion on any written estimate you’ve already received.
We Also Serve Cities Near Lakehills
Barrett & Sons Construction serves the whole Bandera County and northwest Bexar County area. If you’re in Helotes, Lackland Air Force Base, Leon Valley, or Fair Oaks Ranch, our Home Additions & ADU in Lakehills team covers those communities too. Same owner-operated crews, same written change orders, same 90-Day Done Right Promise.
Serving Lakehills, TX - Our Local Coverage Area
We’re based in the Lakehills area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Home Additions & ADU in Lakehills
Start with the flood determination, then the GBRA shoreline easement check, then your design. The finished floor elevation must sit above the base flood elevation, and the structure must respect the waterline setback, which often forces a redesign mid-permit if you drew plans first. Call (877) 610-1318 and we’ll run both checks before you spend a dollar on drafting.
We schedule Lakehills projects every week, and Tom or one of his sons typically walks the property within a few days of your first call. We coordinate scheduling from our San Antonio office but our crews serve Lakehills locally, so you’re not waiting on a crew from another metro. The estimate is free, and there’s no trip charge inside the county.
Yes. We work throughout the 78056 ZIP code, from the shoreline lots near Medina Lake to the newer Hill Country-style homes on the ridgelines. If you’re off Park Road 37, Wharton’s Dock Road, or any of the lake-access streets, we know the terrain and we know the rock.
Generally, yes, and mostly because of the limestone. Digging footing trenches in Bandera County usually requires hydraulic rock-breaking equipment, which flatland San Antonio neighborhoods never need. If your lot is near the lake, floodplain elevation and shoreline easement compliance add design and permitting cost. That’s not an upcharge, it’s the real cost of building here, and we put it in writing up front.
Yes. Every construction and remodeling job we finish, including ADUs and room additions in Lakehills, carries the written 90-Day Done Right Promise. If something isn’t right, one call brings Tom Barrett back. That promise is on the contract, not in the fine print.
Ready to talk about your Lakehills addition or ADU? Call (877) 610-1318 for a free estimate, and ask about the permanent Senior & Veteran 10% discount and the $40 Off Any Repair Over $200 offer.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Lakehills and Bandera County since 1998.







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