







A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateFast, Reliable Home Addition Contractor Across Austin
Adding space to your Austin home usually means opening up a house built between 1940 and 1975, and that is where the real cost hides. We are Seedling ADU Austin, and our Home Addition Contractor team runs an inspection-first process so you know the full price before demolition starts, not after. If you live in Hyde Park, Crestview, Allandale, Travis Heights, or anywhere else in Austin, call (254) 615-3842 and we will walk your lot, check your walls, and hand you a written price before a single tool comes off the truck.
Why Seedling ADU Austin Is Austin’s Preferred Home Addition Contractor Company

Our clients in Austin keep telling us the same thing: they expected chaos, and instead they got a crew that showed up in uniform, laid drop cloths across the living room, and sent a photo of the clean-up before leaving every afternoon. That is the Cedarwell Care Promise, and it applies to every home addition we build in Austin. Shoe covers go on before a boot crosses your threshold. Pet-safe products get used wherever a safer option exists. Sanding dust does not drift into the kitchen because we seal the work area first.
Led by Ben Ortega, our Austin team has spent enough time inside 1940s bungalows and 1960s ranch homes to know what hides behind those original walls. We do not flinch when we find knob-and-tube wiring. We open the wall, show you what we found, price the fix in writing, and get your approval before we proceed. Every job is covered by our 365-Day Done Right Promise: if it is not done right, we make it right, in writing, for a full year after completion. That is the standard for every room addition, second story addition, sunroom, bathroom addition, and bump-out we build in Austin.
Bathroom Addition Contractor in Austin
A bathroom addition contractor in Austin takes on work that is as much about what is behind the drywall as what goes in front of it. In a 1952 Crestview bungalow, adding a bathroom means opening a wall that may still carry live knob-and-tube wiring, and that electrical correction has to happen before tile work begins. For a typical bathroom addition in Austin, expect to budget $45,000 to $85,000 depending on whether you are adding a half bath off a hallway or a full primary bath with a walk-in shower and freestanding tub. That range assumes an inspection-first process with allowances written into the contract, so the number does not jump after demo.
When a homeowner in Austin needs a bathroom addition, it is usually because the household has outgrown a single shared bath, or an aging parent is moving in and needs ground-floor access. The work involves framing new walls, running supply and drain lines, waterproofing the wet zone, and tying into the existing stack. In older Austin homes, the vent stack itself often needs replacement because the original cast iron has rusted through.
What our bathroom addition process covers
We start by tracing the existing plumbing and checking what the fixtures are actually connected to. If the main line is still original galvanized steel, we write that replacement into the scope before we ask you to sign. Every bathroom addition includes a continuous waterproofing membrane at the shower or tub surround, not just cement board and hope.
How the Cedarwell Care Promise works during a bathroom addition
Bathroom additions mean plumbing work, and plumbing work means saws and reciprocating tools running for several days. We schedule the noisiest cuts for mid-morning, after school drop-off, and we place HEPA air filters at the work zone boundary. Floors between the bathroom and the front door get covered with rosin paper and drop cloths, and your cleanup photo arrives before the crew does.
Bedroom Addition Contractor in Austin

A bedroom addition contractor in Austin works on homes where the floor plan simply cannot give a growing family another private room. In a 1960s Allandale ranch, that typically means extending the footprint into the side yard or converting an underused porch, and the first thing we check is whether the existing electrical panel can carry the new circuit load. A bedroom addition in Austin runs $40,000 to $90,000 depending on square footage, whether a bathroom is attached, and what the wall inspection reveals. That range includes structural upgrades if the original framing is undersized.
Bedroom additions in Austin come in two common forms: a true attached addition with new foundation and roof tie-in, or a conversion of an existing garage or bonus room into conditioned living space. The garage conversion route often saves money on framing but may trigger different code requirements for insulation and egress windows. Either way, we write the full scope before we start, including the electrical and waterproofing corrections that Austin’s pre-1970s homes almost always need once a wall is opened.
What a bedroom addition reveals in a 1950s Hyde Park bungalow
If your home still has its original service panel, a bedroom addition typically triggers a panel upgrade because the added square footage requires new arc-fault circuit breakers, and an old fuse box or 60-amp service will not pass inspection. We inspect for this before quoting so the upgrade is in your number from day one.
How we protect your family during a bedroom addition
Bedroom additions often happen at the end of a hallway where your kids sleep, so we isolate the work zone with zip walls and keep the noise schedule respectful of nap times and early bedtimes. The crew wears uniforms and name badges, so you always know who is in your home. And yes, shoe covers stay on every single time.
Trusted Brands We Service in Austin
Austin homeowners researching detached ADU Builders - Austin and prefab additions come to us already familiar with the manufacturers they want. We work directly with Abodu, Cover, and Tuff Shed, and we build with James Hardie siding and trim for homes that need to survive Austin’s UV exposure and summer humidity without warping or fading. Because our crews work with these products day in and day out across Austin, we can tell you honestly how a panelized Tuff Shed shell compares to a precision-built Abodu unit on your specific lot, with your specific tree coverage and setback constraints. You get a written price for each option, not a sales pitch for whichever one we happen to prefer selling that month.
Common Home Addition Contractor Problems We See in Austin Homes
- Knob-and-tube wiring still live behind original walls. In homes built before roughly 1960, the old cloth-insulated wiring is often still carrying current, and any addition that opens those walls triggers a code requirement to replace it. We inspect first, write the allowance into the contract, and show you the wire before we remove it.
- Failed waterproofing at the roof-wall intersection. Austin’s summer storms are sudden and heavy, and a contractor who reuses old step flashing or omits a continuous peel-and-stick membrane will hide rot inside your new ceiling within two years. We install a continuous membrane at every roof-wall tie-in, flashed properly over the shingle line.
- Heritage live oak roots dictating the entire addition footprint. In neighborhoods like Travis Heights and Crestview, a single protected live oak can force a foundation redesign that avoids the critical root zone. We bring in an arborist before we finalize the foundation plan, because Austin’s heritage tree reviewer will flag a trench that cuts major roots.
- Overloaded electrical panels like Zinsco or old Federal Pacific. A 1960s Allandale ranch often still has a Zinsco panel that was recalled but never replaced, and tapping new circuits into it creates a fire hazard that an Austin inspector will catch on final. We flag the panel in our initial inspection and price the replacement into your written scope.
Pricing for Home Addition Contractor in Austin, TX
A home addition in Austin typically runs $150 to $350 per square foot depending on the scope, with a small bump-out landing around $30,000 and a full primary-suite addition with a bathroom reaching $110,000 or more. The biggest drivers are what is behind the wall (electrical, framing, waterproofing), whether the addition is attached or a separate structure, and what your lot’s impervious cover limits allow. A bedroom addition in Austin ranges $40,000 to $90,000, a bathroom addition $45,000 to $85,000, and a second story addition generally starts at $90,000 and runs upward from there depending on how much of the first floor must be reinforced. Every Seedling quote is a written, line-item price provided before any work begins, and no surprise line item ever appears after crews arrive. Call (254) 615-3842 for a free estimate and we will give you a number you can actually plan around.
We Also Serve Cities Near Austin
Our crews work throughout the Austin metro, including Home Addition Contractor in Austin itself, plus Cedar Park, Round Rock, Leander, and Kyle. If you live in one of those surrounding communities and need a home addition built with the same inspection-first process and written pricing, call (254) 615-3842 and we will schedule a walkthrough at your property.
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.
FAQs About Home Addition Contractor in Austin
We typically find live knob-and-tube wiring, original 2×4 roof rafters that are undersized by current code, and tar paper waterproofing that crumbles on contact, all of which must be corrected before the addition can pass inspection. On a 1952 Crestview bungalow, our crew opened a rear wall for a primary-suite addition and found exactly that: live knob-and-tube, rafter ties pulling away from the ridge board, and decayed felt waterproofing. Our inspection-first process had already written allowances for rewiring and structural repair into the contract, and we priced the sistering and new Simpson H1 tie detail in writing before driving a single nail. Call (254) 615-3842 to schedule your own inspection-first estimate.
Heritage live oaks in Travis Heights can dictate the footprint, foundation depth, and even the roofline of your addition, because Austin’s heritage tree ordinance protects the critical root zone and triggers a stop-work order if major roots are cut. We bring in an arborist before we finalize foundation plans, and in some cases we design pier-and-beam foundations that span over roots rather than trenching through them. A contractor who ignores the tree either kills it or gets shut down mid-job by the city reviewer. Call (254) 615-3842 and we will walk your lot with the arborist’s map in hand before we quote.
Yes, in most cases an original 1960s panel, especially a Zinsco or old Federal Pacific, will not pass inspection once you add new circuits for a bedroom addition, and Austin code requires arc-fault protection on those circuits. We inspect the panel during our first walkthrough and write the upgrade into your contract as an upfront line item, not a surprise after the walls are open. The cost is typically $3,000 to $6,000 depending on the service size and whether a new riser is needed from the meter. Call (254) 615-3842 for an exact price on your specific home.
Because Austin’s flash flood risk means a small addition that changes the roofline or adds a roof-wall intersection can channel water against the existing foundation if the flashing and drainage are not done correctly, leading to hidden rot within two rainy seasons. We install a continuous peel-and-stick membrane at every roof-wall tie-in and grade the surrounding soil away from the addition so water never pools against the slab or foundation wall. This matters as much on a 60-square-foot bathroom addition as it does on a full second story, because the failure happens quietly and expensively. Call (254) 615-3842 and we will review your drainage situation during the free estimate.
Austin’s McMansion Ordinance limits the floor-to-area ratio of your lot, which means some additions require a variance or a smaller footprint than you originally wanted, and that entitlement process adds time and cost before construction starts. For a detached addition on a small central Austin lot, the impervious cover limits and heritage tree rules often mean the addition gets placed in the backyard with careful attention to setbacks. We handle the permit and code research as part of our written estimate, so the timeline accounts for city review from the beginning. Call (254) 615-3842 to talk through what your specific lot allows before you commit to a design.
Written by Ben Ortega, Owner at Seedling ADU Austin, serving Austin, TX.









