Home Additions & ADU in Shady Hollow - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Shady Hollow

A home addition or detached ADU in Shady Hollow typically runs $45,000-$130,000 for a ground-up addition and $90,000-$220,000 for a new detached ADU, with garage conversions landing between $30,000 and $80,000. Those numbers assume something we know well: almost every lot in 78739 sits under protected live oaks and cedar elms, which means Heritage Tree permits, arborist reports, and critical root zone plans shape the scope before a single footing goes in. Tom Barrett and his sons work these constraints every week. Call (877) 610-1318 for a free estimate built around your actual lot, not a square-foot price someone quoted over the phone.

Call (877) 610-1318

We’ve been at this since 1998, and Shady Hollow is the kind of neighborhood where the permit inspector knows the tree ordinance better than most builders do. That’s not a complaint. It’s the reason we like working here.

Key Takeaways:

• Shady Hollow additions and ADUs run $45,000-$220,000 depending on scope, tree protection, and foundation engineering.
• Heritage Tree ordinance compliance (trunk diameter ≥19 inches) is the single biggest schedule driver in 78739. Budget for arborist reports and Urban Forestry review before dirt moves.
• Every price change arrives as a written change order. The allowance that isn’t on paper is a surprise waiting for a date.
• Permits pulled and inspections signed on every eligible job. The permit inspector works for you, not for me, and that’s exactly how we treat him.

Why Barrett & Sons Construction Is Shady Hollow’s Preferred Home Additions & ADU Company

We’re the Home Additions & ADU crew that lives with the same trees you do. Tom Barrett founded this company in 1998, and his sons run the crews. When we bid a second-story addition off Brodie Lane or a detached ADU near the Slaughter Creek greenbelt, the person who signs the contract is the same person who shows up on site. No franchise. No strangers from out of state. Our Shady Hollow customers call one number and get a live person, 24/7, not a voicemail box.

Shady Hollow homeowners have told us stories about national outfits that quoted one price on the phone and handed them a different bill at the door. We don’t work that way. A written change order lands in your hand before any scope change touches the job. If the arborist says the root zone forces us to hand-dig pier holes instead of augering, you’ll see that cost on paper before the shovel moves, with a reason attached.

We also carry the 90-Day Done Right Promise on every contract. If something isn’t right, one call brings Tom back. No fine print, no argument. That’s the whole point of a name on the truck.

Our Home Additions & ADU Services in Shady Hollow

Shady Hollow lots are tight, tree-covered, and built on Austin’s most dramatic clay soils. The work we do here has to account for all three. These are the services Shady Hollow homeowners call us about most.

ADU Design & Permitting

This is where Shady Hollow ADUs are won or lost. The Heritage Tree ordinance, Slaughter Creek watershed impervious cover caps, and City of Austin Urban Forestry review all sit between you and a building permit. We handle the arborist coordination, the critical root zone plan, the watershed calculations, and the permit package as one connected scope. In Shady Hollow, a detached ADU without this front-end work isn’t a project. It’s a stop-work order waiting to happen.

New Detached ADU

A new detached ADU in Shady Hollow typically runs $90,000-$220,000. The spread comes down to tree protection, foundation engineering, and how much of your lot’s impervious cover budget is already used up. We’ve built ADUs where the foundation had to float on piers threaded between protected roots, and we’ve built them where the site was clean. You’ll get a line-item scope either way, with every allowance in writing.

Garage Conversion ADU

Converting an attached or detached garage in Shady Hollow runs $30,000-$80,000. These projects move faster than new builds because the shell already exists, but don’t assume they’re simple. Many 1980s-era Shady Hollow garages were built on slabs never engineered for living space, over expansive Blackland Prairie clay. We check the slab, the setbacks, and the tree ordinance trigger before we quote. If the slab needs structural work, you’ll know in the estimate, not after demo.

Junior ADU & Interior Conversion

A junior ADU, typically carved out of an existing bedroom or bonus room with its own entrance and kitchenette, is the least expensive way to add rentable or family space in Shady Hollow. These jobs often don’t trigger the same site disturbance as a detached build, but they still fall under current Austin energy code, which means insulation, windows, and HVAC get scrutinized. Good. That’s how a 40-year-old house stops leaking air.

Trusted Brands We Service in Shady Hollow

We install materials you can look up. On Shady Hollow additions and ADUs, that means window packages from Simonton and Ply Gem, with impact-rated options from PGT when the project calls for it. We don’t pull mystery brands off a van and call them premium. Every window, door, and finish material gets named in the scope, in writing, before we order it. If it’s on the truck, it’s in the contract.

Common Home Additions & ADU Problems We See in Shady Hollow Homes

• Tree ordinance surprises. A homeowner starts a detached ADU, the excavator shows up, and someone reports work near a 24-inch live oak. No arborist report, no Urban Forestry approval. Fines and a stop-work order add four to six weeks. We start with the arborist, not the backhoe.
• Slab heave from Blackland Prairie clay. Shady Hollow sits on the Balcones Escarpment transition zone, where expansive clay meets fractured limestone. Seasonal drought-to-rain cycles move these slabs. If a new addition’s foundation isn’t engineered for that movement, doors and windows bind within two seasons. We engineer for the soil first.
• Watershed impervious cover caps. Slaughter Creek ordinances cap how much of a lot can be covered by hard surface. Add a patio or a detached ADU without running the impervious cover math, and you’re looking at costly redesign and replanning. We run the numbers before we draw the plan.
• Undersized structural headers on garage conversions. Many original Shady Hollow garages were framed with headers too small for a widened opening or a second-story load. We see this on nearly every garage conversion. The fix isn’t optional, and it’s never hidden. It goes in the written scope.

Pricing for Home Additions & ADU in Shady Hollow, TX

The Shady Hollow Tight-Lot Playbook

Shady Hollow was deliberately developed in the 1980s and 1990s around its mature live oak and cedar elm canopy. Virtually every lot in 78739 has trees that trigger Austin’s Heritage Tree ordinance, trunk diameter 19 inches or larger. That ordinance requires an ISA-certified arborist report, a critical root zone plan, and City of Austin Urban Forestry review before any foundation, addition, or flatwork can begin. Builders working a few miles south in Buda or Kyle never deal with this. In Shady Hollow, it’s the defining site constraint. It can stall an ADU permit for weeks and add thousands to the budget. We build it into the schedule from day one, so the tree protection isn’t a surprise, it’s a line item.

On a tight lot off Brodie Lane, our crew framed a second-story addition while working under a 24-inch live oak’s critical root zone. We hand-dug pier holes to avoid root damage, staged materials on a remote driveway to keep the drip line clear, and used a small excavator with turf tracks. The arborist-approved plan added three weeks to the rough-in schedule. It kept the tree healthy, and it passed every inspection sign-off without a change order. That’s how we work here.

Staging on a tight Shady Hollow lot matters. We don’t drop a dumpster on the root zone. We don’t park the skid steer on the drip line. We walk the access path with you before we bid, because access affects the quote. A second-story addition with a 40-foot clear run from the street prices differently than one where every stud has to be walked through a side gate. If the neighbors share a fence line, we handle party-wall notice properly and keep noise within Austin’s work-hour ordinances. A well-run site keeps neighbors on your side, and in Shady Hollow, neighbors notice everything.

Get the real Shady Hollow playbook for additions and ADUs, where Heritage Tree permits, watershed caps, and expansive clay force a different scope of work than anywhere else in the Austin metro. That’s what we write into every bid.

We Also Serve Cities Near Shady Hollow

We work throughout the Austin metro, and our Shady Hollow crews regularly run jobs in Buda, Austin, Kyle, and Bee Cave. Different soils, different tree ordinances, same name on the truck. If you’re in one of those cities and need Home Additions & ADU work, the same Tom Barrett answers the phone.

FAQs - Home Additions & ADU in Shady Hollow