A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted Home Addition Contractor for Austin Homeowners
Adding onto a home in Austin means working with limestone soil, hundred-degree summers that bake exterior materials, and neighborhoods where mature live oaks can dictate where you’re allowed to build. It’s not a simple framing job. Ben Ortega, owner at Seedling ADU Austin, has built additions across Hyde Park, Crestview, Allandale, and down through Circle C, and he’ll tell you the same thing he tells every family: the plans matter less than the preparation. A home addition contractor in Austin who understands the city’s shifting clay soil and permitting process saves you from cracked slabs and stalled inspections. We put a written price in your hand before any crew member sets foot on your property, and every job is backed by our 365-Day Done Right Promise. Call (254) 615-3842 to talk through your project.
Key Takeaways
- Every Seedling ADU Austin home addition starts with a written, line-item price before work begins – no change orders appear after the crew arrives.
- The 365-Day Done Right Promise covers every addition we build. If it’s not right, we make it right.
- Our crews follow the Cedarwell Care Promise: shoe covers, drop cloths, pet-safe products, and a clean-up photo before they leave each day.
- We work with Abodu, Cover, Tuff Shed, and James Hardie products so you’re not locked into one builder’s preferred material.
- Ben Ortega answers questions directly. A live person answers the phone 24/7 during your build.
Sunroom Addition
A sunroom addition gives you a room that feels outdoors without the mosquitos, the July heat index, or the sudden April hailstorm. In Austin, we see families add sunrooms off the back of the house facing east so morning light fills the space without turning it into an oven by 2 p.m. A glass-heavy sunroom in Austin typically runs $28,000 to $72,000 depending on glazing, foundation work, and whether you’re tying into existing HVAC or adding a ductless mini-split. The thing most homeowners don’t plan for: Austin’s clay soil expands and contracts enough that a sunroom slab needs deeper piers than what a handyman would pour. We handle that from day one.
Glazing choices that matter here
Low-E glass is not an upgrade in Austin. It’s the baseline. Without it, your sunroom becomes a greenhouse by mid-morning. We spec insulated low-E units as standard and walk you through which wall gets the most afternoon sun so you can decide where to put operable windows versus fixed glass.
Foundation and drainage specifics
East Austin and areas near the Colorado River have expansive clay that shifts seasonally. We won’t pour a slab without a geotech review and proper piers or beams. That’s the difference between a sunroom that stays square for twenty years and one that starts popping drywall seams in two.
Room Addition Contractor
A room addition contractor in Austin handles the project end to end: foundation, framing, roof tie-in, electrical, drywall, finish work, and the city inspections that come with each phase. You need this when the extra bedroom, office, or flex space can’t be carved out of existing square footage. In Austin, a ground-floor room addition typically runs $175 to $320 per square foot, so a 400-square-foot bedroom and bath addition lands between $70,000 and $128,000 depending on finishes and site conditions. At Seedling ADU Austin, we give you a written price that includes materials, labor, permits, and site cleanup. That number doesn’t move unless you change the scope.
Tying into the existing roof
The roof tie-in is where cheap additions fail in Austin. Our carpenters strip back shingles, integrate underlayment and flashing properly, and make sure the new roof plane sheds water the way the original one did. No exposed fasteners, no kickout flashing omitted at the wall intersection.
Dust control inside the living space
We hang plastic containment and run a negative-air fan when we open a shared wall. Your furniture stays covered, your floors stay protected with drop cloths and shoe covers are mandatory for anyone entering the house. The Cedarwell Care Promise applies to every day we’re on site, not just the final walkthrough.
Second Story Addition Contractor
A second story addition contractor takes on the structural question most builders won’t touch: can your existing foundation and first-floor framing carry another level? In many Austin homes built before 1990, the answer requires engineering. We start with an structural evaluation, not a sales pitch. A second-story addition in Austin typically runs $200 to $385 per square foot, so adding two bedrooms and a bath upstairs – roughly 900 square feet – falls between $180,000 and $346,500. That range accounts for whether we’re reinforcing the existing slab, adding steel beams, or in some cases limiting the footprint to reduce load on the original structure.
Engineering before estimating
Ben Ortega won’t give you a number on a second story until a licensed structural engineer has looked at the existing framing, slab, and soil report. In areas like Brentwood or Rosedale where homes sit on pier-and-beam, the math is different than a slab-on-grade in Mueller. You get a real scope, not a guess.
Living through an upstairs addition
We sequence the work so your family stays in the house as long as possible. Roof cuts are scheduled in one stretch, not spread across weeks. And when we open the ceiling to place beams, we cover everything below and clean the same day. Quiet tools near bedrooms are part of the standard plan.
Garage Addition Contractors
Garage addition contractors build new attached or detached garage spaces, but in Austin the more common request is a garage that doubles as storage, workshop, or a future conversion to an ADU. A standard two-car detached garage addition in Austin runs $45,000 to $85,000. An attached garage with a finished interior and electrical panel upgrade runs $65,000 to $120,000. The smartest move in this market: build the garage with ADU-ready infrastructure – deeper footings, plumbing stub-outs, and a 200-amp subpanel – so the future conversion costs less and delivers more. Seedling ADU Austin works with home addition contractors in Round Rock and surrounding communities on exactly this kind of phased project.
ADU-ready from day one
We frame garage spaces with ceiling heights, window placements, and wall insulation that meet ADU conversion standards. That means if you decide in three years to turn the garage into a rental unit or in-law suite, you’re not tearing out drywall or upgrading the slab. The garage works now and converts later.
Materials that hold up in Texas heat
We spec James Hardie siding on exterior walls so the garage doesn’t fade, warp, or invite termites the way wood siding does here. Trusses get proper ventilation, and the slab gets a vapor barrier that matters more in Austin’s humidity than most people realize.
Bathroom Addition Contractor
A bathroom addition contractor solves the math problem of too many people and too few showers. Austin homes built in the 1950s and 60s – think Allandale, Crestview, and Brentwood – often have one bathroom for three or four bedrooms. Adding a second full bath typically costs $38,000 to $72,000 in Austin, depending on whether we’re tying into existing plumbing, running new drain lines, or adding a bathroom above a garage or slab. We pull permits, install properly vented drains, and waterproof the shower to code. No shortcuts that show up as mold or sewer gas later.
Plumbing realities in older homes
Cast-iron drain lines in an older Austin house may be original. We inspect before we quote so the written price accounts for what’s actually underground. If you need a partial re-pipe or line replacement, that’s in the estimate up front, not a surprise change order.
Waterproofing, not just tile
We use surface-applied waterproofing systems behind the tile, not just cement board. That’s the difference between a bathroom that lasts and one that leaks behind the wall in a year. Schluter or equivalent systems are part of our standard spec.
Bedroom Addition Contractor
A bedroom addition contractor helps families who’ve outgrown their floor plan but don’t want to move. In Austin’s current market, adding a primary bedroom suite often costs less than selling, paying closing costs, and buying a bigger house at today’s rates. A ground-floor bedroom addition with a closet and en-suite bath runs $65,000 to $140,000 in Austin depending on size and finish level. At Seedling ADU Austin, we treat each bedroom addition as a new build within your existing home – proper egress, insulation, HVAC sizing, and closet layout are all in the written scope.
Egress and building code
Every bedroom needs a second means of escape. We size windows to meet Austin’s adopted building code, and we don’t try to call a bonus room a bedroom if it doesn’t have proper egress. You get a legal bedroom, not a listing stretching the truth.
HVAC sizing for the added square footage
We calculate how the new bedroom affects your current system. Sometimes we add a ductless mini-split; sometimes your existing unit has enough capacity. Either way, it’s in the written estimate before we start. No hot room in August that we “didn’t expect.”
Brands We Service
We install and finish Abodu units, and we’ve worked through their full permitting process in Austin’s specific zoning environment. Their compact ADU models fit lots in neighborhoods like Travis Heights and Zilker where side setbacks are tight. We know how to place the unit, handle the crane or panel delivery, and tie in utilities cleanly.
For garage additions and exterior cladding, we use James Hardie fiber cement almost exclusively. It holds paint longer in the Texas sun, resists moisture better than wood or vinyl, and handles the hail we get in spring. We also install Tuff Shed structures for clients who want a permitted outbuilding that can serve as a workshop, studio, or storage space. Whether you have an Abodu in mind, want James Hardie siding, or are comparing Tuff Shed against a custom build, we can help you sort through the options.
Signs You Need a Pro Right Now
- Doors that stick or won’t latch. In Austin, this often points to foundation movement in the clay soil, not just humidity. If multiple doors in different rooms are misbehaving, the slab may be shifting. A professional evaluation before adding on can save you from building on top of an existing problem.
- Cracks wider than a quarter at drywall corners or in the ceiling. Diagonal cracks at corners, especially above doors and windows, indicate structural stress. An addition makes these worse if the underlying cause isn’t addressed first.
- Water staining on interior ceilings after rain. Austin gets sudden downpours and occasional hail. If you see new water marks after a storm, the roof may have hidden damage that a home addition would seal in. We inspect the roof-to-wall intersections before framing anything new.
- Uneven floors you can feel when you walk. Slab homes in East Austin and pier-and-beam homes in central neighborhoods settle differently. Sloping floors can signal failing piers or a cracked slab. Any addition tied to that structure needs an engineer’s read first.
- Your family has outgrown the floor plan and you’re considering moving. This is the sign most people don’t act on. In Austin’s current market, the cost of selling, buying, and moving often rivals the cost of a well-planned bedroom or bathroom addition. We’ll give you a written number so you can compare honestly.
Our Process, Step by Step
- 1
Phone conversation and site visit. We talk through your goals, then Ben Ortega walks the property. We look at foundation condition, roof tie-in points, set-back lines, and where the addition can physically go on your Austin lot. No charge for this first visit.
- 2
Written scope and price. You receive a line-item estimate covering all materials, labor, permits, dumpster fees, and site protection. This is the number we build to. If site conditions change the scope during construction, you approve any adjustment before we proceed.
- 3
Permitting with the City of Austin. We prepare the drawings, submit to the Development Services Department, and work through review comments. Austin’s permitting process can take weeks; we track it so you’re not making weekly calls to the city.
- 4
Construction with daily cleanup. Our crew arrives in uniformed, background-checked teams. Shoe covers inside, drop cloths on all walking paths, and a photo of the cleaned work area before we leave each day. Work areas are contained so your kids and pets stay safe.
- 5
Final walkthrough and Done Right Promise. We walk the addition with you, item by item, and fix anything you flag before we consider the job complete. The 365-Day Done Right Promise starts the day you sign off. If something fails in the first year that’s our work, we’re back to fix it.
How Much Does Home Addition Contractor Cost in Austin?
A typical home addition in Austin costs between $175 and $385 per square foot depending on the type of space and the condition of your existing structure. Here’s what that looks like in real numbers for common projects:
- Sunroom addition: $28,000 to $72,000
- Ground-floor room addition: $175 to $320 per square foot
- Second-story addition: $200 to $385 per square foot
- Detached garage addition: $45,000 to $85,000
- Attached finished garage: $65,000 to $120,000
- Bathroom addition: $38,000 to $72,000
- Bedroom with en-suite bath: $65,000 to $140,000
What moves the price in Austin? Foundation work is the biggest variable. A slab on shifting clay may need piers or beams, which adds $8,000 to $25,000 depending on depth and access. The age of your home matters too – older homes in central Austin neighborhoods often have cast-iron drains, undersized electrical panels, and roof structures that need reinforcement. Permit fees with the City of Austin run thousands, not hundreds. And if your lot has protected trees or falls under a neighborhood conservation district, the plan changes. The way to avoid overpaying: get a written line-item price that separates site work, framing, finishes, and permits. Don’t accept a single lump-sum number with no breakdown. A free estimate from Seedling ADU Austin includes the full written scope. Call (254) 615-3842 and ask Ben Ortega to walk your property.
Our Service Area Near Austin
Seedling ADU Austin serves the greater Austin metro. We’re on jobs in Austin proper, from Circle C to Mueller to Tarrytown, and we regularly build in home additions throughout Leander, Round Rock, Cedar Park, Kyle, Taylor, Elgin, Bastrop, Shady Hollow, Jollyville, Lockhart, and Camp Swift. If you’re within an hour of downtown Austin, we can help. For projects in the northern suburbs, our Round Rock home addition team handles the same written-price process and Care Promise standards.
Serving Austin, TX - Our Local Coverage Area
We’re based in the Austin area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
Frequently Asked Questions About Home Addition Contractor in Austin
A home addition contractor in Round Rock or elsewhere in the Austin area is a licensed builder who designs, permits, and constructs new square footage attached to or adjacent to your existing home. In Austin, that means handling foundation engineering, framing, roof tie-ins, electrical, plumbing, HVAC, drywall, and final inspections with the City of Austin. Seedling ADU Austin performs all of this work with a written price and a 365-Day Done Right Promise.
A ground-floor bedroom or bathroom addition typically takes 8 to 14 weeks from permit approval to final walkthrough. A second-story addition takes 4 to 7 months, and a detached garage takes 6 to 10 weeks. Austin’s permitting process adds time before construction starts, usually 3 to 10 weeks depending on the review queue. We’ll give you a truthful timeline in your written estimate. Call (254) 615-3842 to discuss your specific scope.
Home additions in Austin run $175 to $385 per square foot. A simple sunroom starts around $28,000, a full bedroom suite with bath starts around $65,000, and a second-story addition often exceeds $180,000. Foundation work and your home’s age are the biggest price movers. We’ll give you a free written estimate with line items so there are no surprises. Call (254) 615-3842 to schedule a site visit.
Yes. We work directly with Abodu and use James Hardie materials on most exterior work. We’ve also completed projects with Tuff Shed structures and can advise on whether a prefab ADU makes more sense than a site-built addition for your Austin lot. Prefab can save time on permitting and construction, and it’s still backed by our 365-Day Done Right Promise.
We are not an emergency repair service. Our work is planned construction: site visits, written estimates, permits, and scheduled builds. If you have a sudden roof leak or other urgent issue mid-project, a live person answers our phone 24/7 and we’ll coordinate with you immediately. But new additions are scheduled work built with care, not rushed jobs.
Every home addition we build is backed by the 365-Day Done Right Promise. If something we built fails due to workmanship within the first year, we return and fix it at no charge. Manufacturer warranties on materials like James Hardie siding or Abodu structures apply separately. The Done Right Promise is written into your contract, not spoken as a sales line.
Clear the exterior work area of furniture, planters, and anything you want kept clean. Inside, we’ll handle floor and furniture protection with drop cloths and shoe covers. If you have pets, we’ll coordinate containment so the back door isn’t left open during framing. We’ll walk you through a specific preparation checklist before day one, and you’ll have Ben Ortega’s direct line for questions throughout the build.
Schedule Your Home Addition Contractor Service in Austin Today
Adding a bedroom, bathroom, sunroom, or second story to your Austin home starts with one phone call. Ben Ortega will walk your property, talk through what’s possible, and give you a written price before any work begins. No obligation, no pressure, no surprises. Call (254) 615-3842 to schedule your free estimate.
Written by Ben Ortega, Owner at Seedling ADU Austin, serving Austin and the surrounding communities.
