Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Tomball
Adding square footage in Tomball means planning around two things most out-of-town contractors miss: the expansive black clay under your foundation and the Cypress Creek flood-plain rules that can hold up a permit for weeks. A home addition in Tomball typically runs $45,000-$130,000, while a detached ADU usually lands between $90,000 and $220,000. If you’re weighing a garage conversion, expect $30,000-$80,000 depending on plumbing and foundation work. We’ve been building both directions in the 77375 and 77377 ZIP codes long enough to know which lots drain fast and which ones need detention before the first form board goes up. Call (877) 610-1318 and we’ll walk your property with you.
Why Barrett & Sons Construction Is Tomball’s Preferred Home Additions & ADU Company
Tom Barrett started this company in 1998, and his sons run the crews that work Tomball jobs. That’s not a talking point; it’s the reason you’ll see the same faces from the estimate through the final inspection. We publish Tom’s name, address, and license number, and we encourage every Tomball homeowner to look us up before signing anything. The permit inspector works for you, not for us, and we like it that way.
What homeowners in Tomball tell us they value most is the written change order. Every scope adjustment, every allowance, goes on paper before a single nail moves. The allowance that isn’t on paper is a surprise waiting for a date, and you’ve probably already met that surprise with another contractor. We also back every completed job with the 90-Day Done Right Promise, written on the contract, not buried in fine print. If something’s not right, one call brings Tom back.
We answer our own phone at (877) 610-1318, 24 hours a day, seven days a week. Not a voicemail box, not an out-of-state call center. Dispatch and scheduling are coordinated from our Houston office, but the crews serving Tomball live in the area and know the roads off FM 2920 and SH 249 without a map.
Our Home Additions & ADU Services in Tomball
ADU Design & Permitting
Before concrete is poured in Tomball, the site plan has to clear Harris County Flood Control District and City of Tomball drainage review. We handle the full design and permitting package, including flood-plain elevation certificates and detention calculations for properties in the Cypress Creek watershed. If your lot sits in a FEMA Special Flood Hazard Area, your finished floor elevation decision will drive the entire budget, and we’ll walk you through that math before you pay for plans. Our Home Additions & ADU team has seen enough permit cycles in Tomball to know which details trigger review comments and which ones sail through.
Garage Conversion ADU
Converting an attached or detached garage in Tomball runs $30,000-$80,000, with the spread driven by whether you need new plumbing, upgraded electrical service, or foundation leveling. Older homes in the downtown Tomball township stock, particularly the German-settlement-era houses on pier-and-beam, often need floor structure reinforcement before a garage can become living space. We handle that in-house rather than farming it out to a subcontractor you’ll never meet.
New Detached ADU
A new detached ADU in Tomball generally lands between $90,000 and $220,000, depending on size, finishes, and site prep. The black clay under Tomball expands and contracts with every wet-dry cycle, so we specify post-tension slabs or raised pier foundations with the soil movement in mind. That’s not an upgrade; it’s the baseline for a structure that won’t crack in five years. We also design for the high summer humidity with continuous moisture barriers and ventilation that keeps a detached unit from smelling like a storage shed by August.
Junior ADU & Interior Conversion
A junior ADU, typically carved from an existing bedroom, bonus room, or enclosed patio, is the most budget-friendly way to add rental income or multigenerational space in Tomball. These projects often start at the lower end of the $45,000 range when plumbing and egress already exist. In 77375 and 77377, we frequently convert enclosed patios and sunrooms into conditioned space, and we pair the work with proper insulation and vapor barriers for the Gulf Coast humidity. For homeowners already improving kitchens or baths as part of the project, we also handle Kitchen Remodeling in Tomball and Bathroom Remodeling in Tomball under the same roof.
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.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Tomball
We install materials you can look up, not mystery brands off a van. On Tomball addition and ADU projects, that means Schluter waterproofing systems in wet areas, Sterling and Grohe fixtures where plumbing is involved, and Tomball Roofing components when the addition ties into the existing roof line. When you’re spending $45,000 or more on a home addition in Tomball, you should be able to verify every product name before it’s installed. We stock common replacement parts for the brands we install, which means warranty follow-up in Tomball doesn’t require a three-week wait on a freight truck.
Common Home Additions & ADU Problems We See in Tomball Homes
- Foundation movement from expansive clay: The black clay under Tomball shrinks in drought and swells after heavy rain, and additions that weren’t engineered for that movement start separating from the original structure within a few seasons. We see the telltale crack at the tie-in line all over 77375.
- Flood-plain permitting stalls: Portions of both Tomball ZIP codes carry FEMA Special Flood Hazard Area designations, and a site plan that ignores Cypress Creek tributary drainage easements can sit in review for weeks. Outside contractors routinely under-price Tomball jobs because they didn’t account for detention or elevation certificates.
- Humidity-driven mold in converted spaces: Enclosed patios and garage conversions in Tomball that skip proper vapor barriers and ventilation grow mold inside wall cavities within two humid summers. The envelope detail matters more here than it does a county north.
- Mismatched pier-and-beam connections: Older Tomball township homes on pier-and-beam need careful structural transitions when new space ties in, especially along FM 2920’s corridor of early-20th-century houses. A careless connection lets the old and new sections move independently.
Pricing for Home Additions & ADU in Tomball, TX
A full home addition in Tomball typically costs $45,000-$130,000. Detached ADU construction runs $90,000-$220,000, and garage conversions land between $30,000 and $80,000. Junior ADUs and interior conversions often start at the bottom of that addition range when plumbing and egress already exist. What moves the price in Tomball is site work: expansive clay remediation, flood-plain fill and elevation certificates, and drainage detention if your lot drains toward a Cypress Creek tributary. You’ll get a written line-item quote before you sign, and every allowance is on paper. Call (877) 610-1318 for a free estimate with no trip charge inside the county.
Key Takeaways
- Home additions in Tomball: $45,000-$130,000; detached ADUs: $90,000-$220,000; garage conversions: $30,000-$80,000.
- Tomball’s expansive black clay and Cypress Creek flood-plain rules drive foundation and drainage design decisions.
- Every Barrett & Sons job includes permits pulled, inspections signed, written change orders, and the 90-Day Done Right Promise.
- We answer our own phone 24/7 at (877) 610-1318, and estimates inside the county carry no trip charge.
We Also Serve Cities Near Tomball
Our crews take on addition and ADU work throughout northwest Harris County, including Cypress, The Woodlands, Jersey Village, and Spring. Each of those markets has its own soil and drainage character, and we price each one accordingly, no copy-paste quotes. If you’re in Tomball or any neighboring community, Tomball is where we’ve built the deepest local permitting history, and we’d be glad to put that experience to work for your project.
Serving Tomball, TX - Our Local Coverage Area
We’re based in the Tomball 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 Tomball
We typically begin site evaluation and estimating within days of your call to (877) 610-1318, and permitting timelines in Tomball depend on whether your property falls within a FEMA flood hazard area or requires drainage detention review. A straightforward addition on a slab home in Northpointe can be permitted faster than a pier-and-beam addition near downtown Tomball’s older township stock. The honest answer is that we will not rush a permit that protects you, and we’ll give you a realistic timeline in writing before you commit.
Yes, we handle the full ADU design and permitting package for Tomball, including flood-plain elevation certificates and Harris County Flood Control District drainage review. That paperwork is where outside contractors stumble, and we’d rather have it right than have it fast. Call (877) 610-1318 and we’ll tell you whether your lot even needs flood-plain documentation before you spend a dollar on plans.
Yes, but for a local reason: Tomball’s rental demand has grown faster than apartment construction in the northwest corridor, and a legal ADU with its own address and utilities rents at a premium in 77375 and 77377. The catch is that the value only holds if the unit was permitted and built to flood-plain and foundation standards. An unpermitted garage conversion in Tomball is a liability at resale, not an asset, and we won’t build one that way.
Not without a written change order signed by you first. That’s the rule, not the exception, at Barrett & Sons. If we hit a condition we couldn’t see before demolition, like hidden pier-and-beam damage or a clay swell issue under the slab, you’ll get the new scope and the new price on paper before we move. The allowance that isn’t on paper is a surprise waiting for a date, and we don’t do surprises.
Every Barrett & Sons job includes the 90-Day Done Right Promise, written on the contract: if it’s not done right, Tom comes back and makes it right, one call. Materials carry their own manufacturer warranties, and we’re happy to show you those documents before you sign. Call (877) 610-1318 for details on what’s covered and what’s not, in plain language.
If you’re planning a home addition, Windows & Doors - Tomball, or ADU project, start with a conversation, not a commitment. Call (877) 610-1318 and we’ll walk your property, talk about your lot’s drainage and soil, and give you a written line-item estimate with no trip charge inside the county. You’ll get Tom Barrett’s name, address, and license number up front, and you can look all of it up before you sign.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Tomball since 1998.