Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
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AfterFast, Reliable Home Additions & ADU Across League City
A home addition or ADU in League City typically runs $45,000 to $130,000 depending on scope, and that number moves fast once you account for Galveston County flood-zone rules, Beaumont clay soil, and HOA overlays in communities like South Shore Harbour or Westover Park. We’re Barrett & Sons Construction, and we’ve been framing, permitting, and finishing additions across League City long enough to know that the elevation certificate matters as much as the floorplan. If you’re weighing a garage conversion in 77574 or a detached ADU in 77573, call (877) 610-1318 and we’ll walk you through what your specific lot actually requires before you spend a dime.
Why Barrett & Sons Construction Is League City’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998, and his sons run the crews. That means the person you shake hands with is the person whose name is on the truck. League City homeowners have told us the same thing for years: the national outfits quote one price on the phone and hand you a different bill at the door. We don’t work that way. Every scope, every allowance, every price change arrives as a written change order before a single nail moves. If it’s not done right, Tom comes back and makes it right. That’s the 90-Day Done Right Promise, and it’s written on every contract we sign in League City.
We know the difference between building in Tuscan Lakes and building off FM 518 near the historic downtown core. The soils, the flood zones, and the HOA review process all change. A contractor who only works Harris County suburbs will walk into a League City permit office and learn things the expensive way. We already know what Galveston County wants to see, because we’ve pulled those permits repeatedly.
When you call, a live person answers. Not a voicemail box, not an out-of-state call center. And if you want to verify us before signing anything, Tom publishes his name, his address, and his license number. Look it up. Ask anyone on your street. We like it that way.
Our Home Additions & ADU Services in League City
This is our Home Additions & ADU work in League City, focused on the jobs League City homeowners actually ask us about. Each one starts with the same question: what will Galveston County require on this specific parcel?
ADU Design & Permitting
Before we frame anything in League City, we verify the flood-zone designation for your lot, the Base Flood Elevation, and whether your property is inside an HOA with architectural review authority. That sequence saves weeks of rework. We handle the elevation certificate, the site plan, the structural drawings, and the permit package as one scope, in writing, before construction starts.
Garage Conversion ADU
Converting an attached garage in League City usually lands between $30,000 and $80,000. The catch is that many master-planned communities, including Westover Park and Mar Bella, treat a garage conversion as a change to the exterior elevation, which triggers HOA review before the city ever looks at it. We manage that approval path alongside the building permit so you’re not stuck with a stop-work order and fines. In flood zones, the finished living floor still has to meet elevation requirements, which can raise the floor height and squeeze ceiling clearance. We scope that in the first written estimate, not halfway through the job.
New Detached ADU
A new detached ADU in League City typically runs $90,000 to $220,000, and the final number depends heavily on your lot. Homes in 77573 and 77574 sit on Beaumont clay that shrinks in summer drought and swells after Gulf-driven rain. Post-tension slabs that are stable for a 1990s tract house aren’t automatically adequate for a detached structure with its own foundation. We evaluate soil movement before we set forms. And because League City sits inside Texas’s windborne debris region, the windows on that ADU need to be impact-rated or protected by approved shutters. We install Simonton and PGT impact products regularly for exactly this reason.
Junior ADU & Interior Conversion
A junior ADU carved from existing interior space, like a large bonus room or a converted formal dining room, can be the fastest and least expensive path to a rentable or in-law unit in League City. You’re not adding a foundation, which skips the soil analysis entirely. What you can’t skip is the electrical, egress, and fire separation work Galveston County checks at inspection. We pull the permit, schedule inspections, and get it signed off.
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.
Trusted Brands We Service in League City
Flood-zone construction means manufacturers matter. We install impact-rated windows and doors from Simonton, PGT, and CGI, because League City’s windborne debris requirements don’t leave room for off-brand glass. When a window needs to hold up to a hurricane-driven two-by-four, the label on the frame is the first thing the inspector looks at. These are materials you can look up, not mystery brands off a van.
Common Home Additions & ADU Problems We See in League City Homes
- Stop-work orders from HOA architectural review. A homeowner in Tuscan Lakes starts a garage conversion without filing the HOA review first. The HOA finds out, issues a stop-work order, and now the homeowner is paying fines and restarting permitting. We file that review before the first wall comes down.
- The substantial-improvement threshold on Harvey-damaged homes. Galveston County tightened enforcement after 2017. Any permitted renovation exceeding 50% of a structure’s pre-storm market value triggers full flood-zone upgrade requirements. A contractor who doesn’t run that calculation before quoting can push a project over the line mid-build and double the cost overnight.
- Differential settlement at the new-to-old junction. Beaumont clay moves. When an addition ties into an existing slab without accounting for that movement, you get cracks exactly where the new foundation meets the old one, usually within two years. We design the tie-in detail for soil movement, and we’d rather re-shim form boards twice than pour a slab that fights the dirt.
- Missing flood vents on a permitted addition. In a Special Flood Hazard Area, Galveston County requires engineered flood vents on enclosed areas below Base Flood Elevation. A contractor who doesn’t understand flood vent placement gets a failed inspection, and the homeowner sits on a finished room they can’t legally use until the vents are retrofitted. We put the flood vent allowance in writing from the first quote, so nobody is surprised.
Pricing for Home Additions & ADU in League City, TX
League City pricing reflects local code, local soil, and local flood rules. Here are the line-item ranges we quote most often:
| Project Type | Typical League City Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
Where your project lands inside those ranges depends on your flood zone elevation requirements, whether you’re inside an HOA, the condition of the existing slab, and the finish level you want. A kitchenette with Home Depot cabinets costs less than a full kitchen with KraftMaid. We put all of it in writing before work starts. Call (877) 610-1318 and we’ll give you an honest range for your specific League City lot. Free estimates, written change orders, permits pulled, inspections signed.
We Also Serve Cities Near League City
Our crews serve Home Additions & ADU in League City and the surrounding communities: Dickinson, Webster, Bacliff, and Seabrook. Much of that area shares the same Galveston County flood rules and Gulf Coastal Prairie soils, which means the permitting knowledge carries straight across. If you’re in one of those cities and weighing an addition or ADU, call (877) 610-1318.
Serving League City, TX - Our Local Coverage Area
We’re based in the League City 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 League City
Yes, in most cases. Large portions of 77573 sit inside FEMA Special Flood Hazard Areas, and Galveston County’s Flood Damage Prevention Ordinance requires an elevation certificate to establish the Base Flood Elevation before you pour a foundation for a new detached ADU. Our scope includes the elevation certificate as part of the permit package, so you’re not chasing a surveyor at the last minute. Call (877) 610-1318 and we’ll check your specific lot.
No. Westover Park’s architectural review committee treats garage conversions as exterior modifications, which means you need HOA approval before the city permit is issued. Skipping that step gets you a stop-work order and fines. We file the HOA review package at the same time as the building permit so the schedule doesn’t stall. Call (877) 610-1318 for help with the full process.
It means any permitted renovation exceeding 50% of your home’s pre-Harvey market value triggers full flood-zone compliance upgrades. For older pier-and-beam homes near FM 518’s historic downtown core, that threshold often means elevating the entire structure, which can dwarf the cost of the original addition. We verify the threshold calculation in the quoting phase. Call (877) 610-1318 before you commit to a scope.
Yes. League City lies in Texas’s windborne debris region, and Galveston County’s adopted International Residential Code requires impact-rated glazing or approved shutters on all new construction and major remodels. We install impact-rated Simonton, PGT, and CGI windows on every addition we build here. Call (877) 610-1318 to see which product line fits your project and budget.
Because any enclosed area below Base Flood Elevation in League City requires engineered flood vents that let water pass through without compromising the foundation. Galveston County inspectors check for them, and failing that inspection is a project-stopping problem. The allowance isn’t padding; it’s the cost of code compliance. Tom Barrett puts every allowance on paper before framing starts. Call (877) 610-1318 if you want a quote that already accounts for League City flood rules.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving League City, TX.