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 Plano
A room addition or ADU in Plano typically runs $45,000 to $130,000 for a home addition, $90,000 to $220,000 for a new detached ADU, and $30,000 to $80,000 for a garage conversion. Those are the numbers we quote, in writing, before the first hammer swings. If you’re in 75074, 75075, 75086, or anywhere else in Plano and you’re weighing whether to add on or move, call (877) 610-1318. We’ll walk your property, look at what you have, and tell you straight what it costs.
We know Plano’s homes the way only a crew that’s been crawling through them for decades can. The east side’s 1970s tract houses on Fox Creek Drive in 75075, the 1980s two-stories off Independence Parkway, the larger custom builds west of Preston Road in 75093. Each one opens up differently. Each one has its own surprises hiding behind drywall. The difference is whether your contractor knows to look for them before quoting, or discovers them after you’ve signed.
Why Barrett & Sons Construction Is Plano’s Preferred Home Additions & ADU Company
Tom Barrett founded this company in 1998, and his sons run the crews. That’s not marketing language. When we say a Barrett will be on your Plano job site, we mean someone whose last name is on the truck. Our Home Additions & ADU team has torn open enough Plano walls to know exactly what’s behind them: 1970s Romex, undersized framing, and the kind of settling that comes from Blackland Prairie clay expanding and contracting through every North Texas drought-and-rain cycle.
We don’t dispatch strangers to Plano. The same crew members who walk your job before quote are the ones who show up to build it. Background-checked, uniformed, and carrying the Barrett name on their shirts. Ask anyone on your street, or look up Tom Barrett’s license number yourself. We publish it because we want you to check.
Every price change on a Plano job arrives as a written change order before work proceeds. Every scope, every allowance, every surprise found behind a wall gets priced and approved by you, in writing, before we touch it. That’s not a policy we adopted to sound good. That’s the rule Tom put in place after watching too many Plano homeowners get burned by the national outfits that quote one number on the phone and hand you a different bill at the door.
Our Home Additions & ADU Services in Plano
Room Additions
Adding a ground-floor room to a Plano home means working around post-tension concrete slabs. In the 1980s subdivisions that dominate 75074 and 75075, the tendon layout drawings were often never filed with the city, or they’ve been lost over the years. Before we core drill or saw cut, we bring in a GPR scanner to locate tendons. Skipping that step has severed tendons, cracked slabs, and triggered City of Plano stop-work orders. We don’t skip it. A typical room addition in Plano runs $45,000 to $130,000 depending on square footage, foundation work, and what we find when walls come open.
ADU Design & Permitting
Plano’s building department reviews ADU plans against a specific set of zoning and structural requirements, and the process moves faster when the drawings are right the first time. We handle design and permitting as one package. We know which questions the City of Plano reviewers ask, what they flag, and how to get a clean approval without three rounds of resubmittal. Permits get pulled on every eligible job, because the inspector works for you, not for us. That’s exactly why we want him on site.
Second Story Additions
A second story over a Plano home means new loads on footings that were poured for a single-story structure thirty or forty years ago. On a 1979 two-story in 75075, our crew opened a load-bearing wall for a room addition and found original Romex with scorched insulation, undersized 2×4 framing that had twisted over four decades of soil movement, and a leaking exterior wall where the original builder skipped flashing. We re-framed the wall, pulled new circuits, and worked with the City of Plano inspector to get sign-off before drywall. That’s the difference between a quote that holds and one that explodes mid-project.
Garage Conversion ADU
Plano garages from the 1980s and 1990s were built as unconditioned storage, not living space. Converting one to an ADU means insulation, electrical upgrades, plumbing runs, and often foundation work at the slab edge. Garage conversions in Plano run $30,000 to $80,000. The range is wide because what we find under the slab and behind the drywall changes the scope, and we price every bit of it in writing before we start.
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 Plano
When your Plano addition or ADU calls for fixtures, waterproofing, or finish materials, we install brands you can look up yourself. Schluter waterproofing systems in new bathrooms, GAF roofing on new additions, Sterling and Grohe fixtures where the design calls for them. No mystery materials off a van. The same standards apply to the lumber, the fasteners, and the flashing you’ll never see but will depend on for decades. We stock the parts Plano jobs need, and we don’t make you wait on a supply-house backorder while your project sits half-open.
Common Home Additions & ADU Problems We See in Plano Homes
- Post-tension tendon strikes during slab work. Crews from outside the Plano market frequently don’t bring GPR scanning to the job. We do, every time, before any saw cut. A severed tendon means a slab failure, a stop-work order, and a five-figure repair that wasn’t in anyone’s budget.
- Outdated electrical in 1970s-1990s homes. Opening a wall for a room addition in a Plano tract home usually reveals aluminum branch circuits, ungrounded outlets, or Romex that’s been overheating for thirty years. Code triggers a panel upgrade or circuit replacement once the wall is open. If your allowance wasn’t written for it, you’re financing a surprise.
- Undersized and twisted framing. The clay under Plano moves. In the 75075 and 75074 homes especially, decades of heave and shrink have bowed studs and shifted plates. An addition that ties into that framing needs correction work before new framing goes up. A contractor who doesn’t plan for it sends you a change order. We build it into the allowance up front.
- Clay-soil footings that are too shallow. Plano’s expansive black clay requires deeper footings than homes in Dallas or Fort Worth, where the soil profile is different. Pouring an addition on undersized footings here means cracking, door misalignment, and a structural problem you can’t hide. We size footings for Plano’s soil, not for a generic North Texas spec sheet.
Pricing for Home Additions & ADU in Plano, TX
Here’s what Plano homeowners should expect to pay for the most common addition and ADU projects:
| Project Type | Plano Price Range |
|---|---|
| Home Addition | $45,000 - $130,000 |
| ADU Construction | $90,000 - $220,000 |
| Garage Conversion | $30,000 - $80,000 |
What moves the number within those ranges? Square footage, foundation work, whether we’re tying into existing framing or correcting it, and what code upgrades a permit triggers once walls are open. A 400-square-foot ground-floor addition on a clean slab is a different job than a second story over a 1980s house with twisted framing. The estimate is free. The price you get is the price on the contract, and every change after that comes to you in writing before any work happens. Call (877) 610-1318 to schedule your free estimate.
We Also Serve Cities Near Plano
Our crews work throughout the Plano area and the neighboring communities. If you’re in Home Additions & ADU in Plano or just down the road in Lucas, Allen, Murphy, or Sachse, the same local knowledge applies: the same clay soil, the same 1970s-1990s housing stock, and the same need for a contractor who knows what a 40-year-old North Texas house looks like when you open it up. Dispatch and scheduling are coordinated from our Dallas-Fort Worth office, but the crews serving Plano are local, and they know these streets.
Serving Plano, TX - Our Local Coverage Area
We’re based in the Plano 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 Plano
Yes. If your Plano home sits on a post-tension concrete slab, especially in a 1980s subdivision where tendon layout drawings were never filed, a GPR scan is non-negotiable before any core drill or slab saw cut. Skipping it has severed tendons, caused slab failures, and triggered City of Plano stop-work orders. We bring GPR scanning to every Plano job that touches the slab. It’s not optional, and we don’t treat it like an upsell. Call (877) 610-1318 and we’ll explain exactly what it covers.
Opening a wall in a 1970s-1990s Plano home typically triggers electrical upgrades, smoke and carbon monoxide detector additions to current code, and sometimes window egress changes if the new room is a bedroom. If the existing wiring is aluminum or ungrounded, the City of Plano will require a panel upgrade or circuit replacement. These are not surprises to us. They’re line items in the written allowance we put in your contract before we start. Call (877) 610-1318 for a scope that includes them.
We expect them, price them in advance, and document them in writing when they exceed the allowance. Before we open a wall, we build an allowance into your contract for the things Plano homes hide: outdated wiring, undersized framing, failed waterproofing. If we find something beyond that allowance, you get a written change order with the scope and price before work proceeds. Nothing gets touched without your approval on paper. The allowance that isn’t on paper is a surprise waiting for a date.
Plano sits squarely on the Blackland Prairie, where expansive black clay shrinks during drought summers and heaves during heavy spring rains. That movement is more aggressive than the soil profile under Dallas or Fort Worth, so footings here must reach below the active zone. Pour an addition on undersized footings and you’ll get cracking, door misalignment, and a structural fix that costs more than the original footing would have. We size footings for Plano’s clay, every time.
Usually not. A garage conversion in Plano almost always involves cutting the slab for plumbing, which means post-tension tendon location first. Even when the slab is left mostly intact, edge work for insulation, door replacement, and weather sealing touches the concrete. We’ll tell you after we look at your specific garage whether a full ADU conversion makes sense at $30,000 to $80,000, or whether a different layout avoids the slab work entirely. Call (877) 610-1318 for a free estimate and we’ll walk it with you.
Contact Barrett & Sons Construction for Your Plano Addition or ADU
If you’re thinking about adding a room, going up, or building an ADU on your Plano property, start with a contractor who knows what these houses look like on the inside. We’ve been opening Plano walls since 1998, and we put every scope, every allowance, and every change order in writing before work happens. The estimate is free. The conversation is straight. Call (877) 610-1318 and talk to a live person who can schedule your free estimate today. The 90-Day Done Right Promise is written on every contract we sign. If it’s not done right, Tom comes back and makes it right, one call.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Plano since 1998.