A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateTrusted Room Addition Contractor for Austin Homeowners
A room addition in Austin isn’t a weekend project. It’s a structural change to your home, and it has to hold up through summer heat, spring storms, and the occasional freeze nobody planned for. Most homeowners who call us have already been through it once: a contractor who disappeared after the deposit, a price that climbed every week, or a permit that never got pulled. We work differently. Fielding ADU Austin builds room additions, sunrooms, in-law suites, and ADU conversions with a written price before any work starts and a Room Addition Contractor Maintenance Checklist for Austin Homeowners backed by a one-year written guarantee on everything we build. Reed Calloway leads our Austin operation under The Garrison Standard, which has guided this company since 2006. To talk through your project with a real person, call (361) 309-9568 any time, day or night.
Sunroom Builders
Sunroom Builders handle glass-walled or heavily windowed additions that bring daylight into a home without the full cost of a conventional room addition. You need one when you want a reading room, a plant room, or a breakfast space that feels outside without being outside, and you need one built right because Austin’s UV load will fade furniture and overheat a poorly sealed sunroom within two summers. Fielding ADU Austin designs and builds sunrooms with low-E glass, proper roof ventilation, and insulation rated for central Texas heat, and we put the full price in writing before a single board is cut. A sunroom addition in Austin typically runs $25,000 to $85,000 depending on glazing packages and foundation work, before permit fees.
Glass and Glazing Choices
We spec low-E double-pane glass as the default for Austin sunrooms. The coating cuts solar heat gain by roughly half compared to standard glass, which keeps the room usable from March through October. We’ll show you the difference in writing before you commit.
Frame material matters more than people expect. Aluminum conducts heat, vinyl expands too much in 105-degree weather, and a hybrid aluminum exterior with a thermally broken interior holds up best. We recommend what survives Austin, not what looks good on a showroom floor.
Foundation and Tie-In Work
A sunroom is only as good as the slab under it. We pour reinforced slabs with proper drainage slope so water never pools against the house, and we tie the new roof into the existing structure with flashing that actually overlaps. Half the sunrooms we inspect in Austin leak at the tie-in line within five years. Ours don’t, and the one-year written guarantee backs that.
Room Additions
Room Additions are ground-up square footage: a new bedroom, a home office, a dining room, or a family space built onto the existing footprint of your house. You need this when the layout no longer works and moving isn’t on the table, and you need our Room Addition Contractor in Austin who knows Austin’s setback rules, foundation requirements, and energy code. Fielding ADU Austin handles the entire addition from foundation to finish, with permits pulled by the book and a written quote that doesn’t change at the door. A standard room addition in Austin runs $40,000 to $120,000 depending on square footage, finishes, and whether plumbing or HVAC extensions are required, before permit fees.
Foundation Work and Soil Conditions
Austin sits on expansive clay soil. It swells when it rains and shrinks when it doesn’t, which is why so many additions in this city develop cracks at the seam. We pour foundations engineered for the specific soil report on your lot, using deeper footings where the report calls for them. That’s the difference between an addition that lasts forty years and one that settles away from the house in five.
Matching Existing Structure
Every addition we build gets matched to the existing roofline, eave depth, and exterior siding so the finished product looks original, not bolted on. We carry James Hardie fiber cement siding on the majority of our Austin additions because it holds paint longer than wood and doesn’t warp in humidity. If your house has brick, we match the brick. If it has Hardie, we match the Hardie.
Modular Home Addition
Modular Home Addition means building the new space off-site in a controlled factory, then craning it onto your prepared foundation and finishing the tie-in on site. You need this when you want a compressed timeline or when your lot makes a conventional build difficult: steep grade, tight access, or a homeowners association that limits how long construction materials can sit in the driveway. Fielding ADU Austin works with leading prefab platforms including Abodu, Cover, and Plant Prefab, and we also build conventional additions when a custom floor plan is required. A modular home addition in Austin typically runs $55,000 to $150,000 before permit fees, depending on the platform and finish level.
Prefab Platform Selection
Abodu units are designed for California-style ADU code and adapt well to Austin’s residential lots. Cover builds panelized structures with a cleaner interior finish than most modular products we’ve seen, and Plant Prefab offers the most design flexibility among the factory-built options. We walk every client through the trade-offs in plain language before any deposit changes hands.
Factory-built doesn’t mean code-free. The city of Austin still requires the same setbacks, the same foundation engineering, and the same energy compliance for a modular addition as for site-built. We pull every permit and schedule every inspection regardless of where the walls were framed.
Site Work and Crane Logistics
Getting a module off a truck and onto a foundation in a tight East Austin lot takes planning. We measure access paths, check overhead clearances, and coordinate crane placement with the city when a street closure is required. This is the part modular companies without local crews get wrong, and it’s the part we’ve handled dozens of times across Austin, Georgetown, and with our Room Addition Contractor in Pflugerville.
Home Addition Plans
Home Addition Plans are the architectural drawings and permit sets that the city of Austin requires before any structural work can legally begin. You need them when you’re adding square footage, changing a roofline, or touching load-bearing walls, and you need them done by someone who understands Austin’s specific building code amendments rather than dropping in a stock design from another state. Fielding ADU Austin produces permit-ready plans for every addition we build, and we submit them to the city with the permit application so you’re not chasing paperwork. Plan fees for a room addition in Austin typically run $2,500 to $6,500 depending on complexity, separate from construction costs.
Setbacks and Variances
Austin’s standard setback is 25 feet from the front property line and 5 feet from the side and rear lines for most single-family lots, but there are exceptions in older neighborhoods like Hyde Park and Zilker where lots were platted before current code. If your addition needs to go closer than the standard allows, we file for a setback variance, which is the city’s written permission to build closer to the property line than the rule allows. That process takes time, and we handle it from start to finish.
Structural Drawings and Engineering
The city will not approve plans without a licensed engineer’s stamp on any foundation, beam, or roof tie-in work. We work with structural engineers who know Austin’s expansive soil conditions and design foundations that won’t fail in a drought cycle. The drawings we submit are specific to your lot, not a recycled template, which is why our permit approvals move faster than most.
In Law Suite Builders
In Law Suite Builders construct attached or detached living quarters designed for an aging parent, an adult child, or a long-term guest who needs a private entrance, a small kitchen, and a full bath. You need this when the alternative is a retirement community or an apartment lease, and you need a builder who understands accessibility requirements, separate utility metering, and the difference between an in-law suite and an ADU under Austin’s code. Fielding ADU Austin builds in-law suites of both types: attached additions with a private entrance, and detached backyard units with their own foundation and address. A detached in-law suite in Austin typically runs $90,000 to $180,000 before permit fees, while an attached suite runs $70,000 to $150,000.
Accessibility and Aging in Place
If the suite is for an aging parent, we spec wider door openings, zero-threshold showers, and blocking in the walls for future grab bars from day one. It costs less to build it in at framing than to retrofit it after a fall, and we’d rather tell you that now than after the fact. The Garrison Code applies here as everywhere: show up in the window, price in writing, by the book, leave it clean, stand behind it for a year.
Detached Suites and Utility Connections
A detached in-law suite in Austin needs its own water tap, sewer lateral, and electrical service, which means trenching from the street or alley and coordinating with Austin Energy and Austin Water. We handle every utility connection and schedule each inspection so the suite is legal to occupy on closing day. Half the detached units we get called about were built by someone who skipped the separate meter, and the homeowner found out when the city sent a notice.
ADU Conversion
ADU Conversion means taking existing space, usually a garage, and turning it into a permitted accessory dwelling unit with a kitchen, bath, and sleeping area. You need this when you have a two-car garage that hasn’t held a car in ten years and you’d rather have rental income or a place for family than a storage bay. Fielding ADU Austin converts garages into legal ADUs under Austin’s current code, which requires insulation, upgraded electrical, and a proper foundation assessment. A garage ADU conversion in Austin typically runs $60,000 to $130,000 before permit fees, depending on whether the existing slab can support the new use or needs to be cut and repoured.
Garage Conversion Requirements
Austin requires that a garage conversion meet the same energy code, egress standards, and fire separation as new construction. That means replacing the overhead door with a wall, adding a proper exterior door, insulating the slab if it sits below grade, and running dedicated circuits for the kitchen. We do all of it and we pull the permit before the first piece of drywall comes down.
Some garages in Austin sit on slabs that were never engineered for living space. If your slab is too thin or has no vapor barrier, we’ll tell you before we quote, because hiding that problem under flooring costs more later. The written price we hand you accounts for exactly what the existing structure can support.
Detached Garage ADUs
A detached garage converts more cleanly than an attached one in most cases, because you already have four independent walls and a roof designed to shed water. We run new water and sewer lines from the house, install a subpanel, and insulate to code. The result is a rental unit or guest house that adds value to the property rather than just taking up space.
Brands We Service
Fielding ADU Austin works with Abodu, Cover, and Plant Prefab on modular and prefab addition projects across the Austin area. We know these platforms’ engineering specifications, their panel connection details, and their tolerance ranges, which means we can prepare your site and foundation to the exact dimensions the module requires. That precision is what separates a clean crane-set from a week of on-site rework.
On conventional builds, we install James Hardie fiber cement siding and work with Tuff Shed-style structures when a client wants a finished backyard space or a workshop-style addition at a lower price point than conventional framing. Whether your project involves Abodu, Cover, Plant Prefab, James Hardie, or Tuff Shed, we handle the plans, permits, site work, and finish. If you have another brand in mind, we’ll assess it honestly and tell you if it’s the right fit for your lot and budget. Our home page has more on the full range of work we do across central Texas.
Signs You Need a Pro Right Now
- Your foundation has visible cracking at the slab edge. Austin clay soil moves every season, and a crack wider than a quarter inch at the slab edge can signal differential settlement. Adding square footage on top of a compromised foundation makes the problem worse, and a pro should assess it before any design work begins.
- Your existing roofline shows sagging or water staining at the eaves. A sagging roofline means the framing is already overloaded or the decking is rotting. Tying a new addition into that structure without a structural review is how ceilings come down.
- You see diagonal cracks above door and window openings inside the house. Diagonal cracks in drywall above openings usually indicate shear stress on the framing. A room addition changes the load path of the entire structure, so this symptom needs an engineer’s eye before construction starts.
- The city has sent a notice about unpermitted work on the property. Austin’s code enforcement department does issue citations for unpermitted additions and ADUs. If you bought a house with an undeclared conversion, you need a contractor who can bring it up to code and clear the violation, not one who hides from the inspector.
- Your electrical panel is already maxed out. Any significant addition will draw more load than most older Austin panels can supply. If your panel is full or the service is only 100 amps, an upgrade may be required before the new space is energized, and it’s better to know that before the walls are up.
Our Process, Step by Step
- 1
Site visit and measurement. We walk your property, measure the existing structure, check the lot lines, and note any site constraints like trees, slopes, or overhead lines. Reed Calloway or one of our senior field leads handles this visit personally, and you’ll know the name of the person on your site before they arrive.
- 2
Written price and scope. After the site visit, we hand you a written price that covers the entire project: foundation, framing, rough-in, finishes, and all permit fees. This is the Garrison Standard: the number you approve is the number on the final invoice, with no change orders unless you request a change.
- 3
Plans and permits. We produce your permit drawings, submit them to the city of Austin, and schedule every required inspection once work begins. You’ll see the permit number, and our name goes on the permit as the responsible contractor.
- 4
Construction and weekly updates. A background-checked, uniformed crew builds your addition on the schedule we agreed to. You get a progress update each week, and if something changes, you hear it from us first, not from a neighbor’s complaint about the noise.
- 5
Final walkthrough and written guarantee. We walk the finished space with you, close out the permit with a passing final inspection, and hand you a written one-year guarantee. If anything fails in that period, we return and fix it at no charge. That’s The Garrison Standard, in writing.
How Much Does Room Addition Contractor Cost in Austin?
A room addition in Austin runs from $40,000 for a simple single-room bump-out to $120,000 or more for a primary suite with a full bath and walk-in closet. A sunroom typically lands between $25,000 and $85,000. A garage ADU conversion runs $60,000 to $130,000. A detached in-law suite sits between $90,000 and $180,000. A modular addition runs $55,000 to $150,000 depending on the platform. These ranges are before permit fees, which vary by project scope but typically add $2,000 to $8,000 in Austin.
What drives the price: square footage, foundation work, utility connections, finish level, and whether the city requires a variance. What doesn’t drive the price with us: your zip code, your budget, or how busy our schedule is. Every estimate we write is free, and it includes a line-item breakdown so you can see exactly where the money goes. To avoid overpaying, get at least three written quotes and compare line items, not just bottom lines. A contractor who won’t put the price in writing before taking a deposit is telling you something with that silence. Call (361) 309-9568 and we’ll put your price on paper.
Our Service Area Near Austin
Fielding ADU Austin builds room additions and ADUs throughout the Austin metro, including Georgetown, Pflugerville, San Marcos, Lakeway, Hutto, Buda, Manor, Brushy Creek, Lago Vista, Wells Branch, and Hornsby Bend. We schedule site visits within a few business days across the service area, and we always confirm the exact appointment window the day before. If your city of Austin permit requires additional review, we handle the communication with the planning department. For a free estimate on a room addition in Austin, call (361) 309-9568. You can also check our Room Addition Contractor in Georgetown and Room Addition Contractor in Pflugerville pages if your project sits in one of those cities.
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 Room Addition Contractor in Austin
A room addition contractor is a licensed general contractor who manages the design, permitting, foundation work, framing, and finish construction of a new living space attached to your existing home or built as a detached structure on your property, including work by a Room Addition Contractor - Manor. In Austin, the contractor must pull permits through the city’s Development Services Department and pass every required inspection before the space is legal to occupy. At Fielding ADU Austin, we handle the entire process and hand you a written price before any work begins. Call (361) 309-9568 to talk through your specific project.
Most room additions in Austin take three to six months from the first site visit to the final inspection, depending on size, foundation conditions, and permit review times at the city. A simple sunroom can be done in eight to ten weeks, while a detached in-law suite with new utility connections usually runs four to six months. We give you a written schedule with your written price, and we update you weekly throughout the build. Call (361) 309-9568 for a timeline specific to your project.
A room addition in Austin typically costs $40,000 to $120,000 before permit fees, with sunrooms at $25,000 to $85,000 and garage conversions at $60,000 to $130,000. The final number depends on square footage, foundation work, finishes, and whether the city requires a variance for your lot. Our estimates are line-item detailed, so you see exactly what each component costs. Call (361) 309-9568 for a free written estimate, no obligation.
Yes. We build with Abodu, Cover, and Plant Prefab on modular and prefab addition projects, and we install James Hardie siding on conventional builds. Tuff Shed-style structures are also an option when the budget calls for a simpler build. We’ll walk you through which platform fits your lot, your timeline, and your budget before you commit to anything. Call (361) 309-9568 to discuss options.
If your existing foundation or framing has failed and you’re planning an addition, we can assess the damage as part of your estimate and tell you what repairs are required before the addition can proceed. A live person answers our phone 24 hours a day, seven days a week, so you can reach us at (361) 309-9568 any time, and we’ll schedule a site visit to look at the problem in person.
Every addition we build is covered by The Garrison Standard, a written one-year guarantee on workmanship. If something fails inside that 365-day period, we return at no charge and correct the defect. The guarantee is spelled out on paper: what it covers, how long it runs, and exactly how we make it right. Call (361) 309-9568 and we’ll show you the document before you sign anything.
Start by gathering your property survey if you have one, noting which direction the sun hits the wall where you want to build, and making a list of what the new space needs to do for you. Then call us at (361) 309-9568 for a free site visit and written estimate. The more specific you are about how the space will be used, the better the design will fit, and the fewer surprises will come up during construction.
Schedule Your Room Addition Contractor Service in Austin Today
Call (361) 309-9568 and talk to a real person about your room addition, sunroom, in-law suite, or ADU conversion. We’ll schedule a free site visit, hand you a written price before any work starts, and stand behind the build with a one-year written guarantee. No pressure, no vague quotes, no surprises at the door.
Written by Reed Calloway, Owner at Fielding ADU Austin, serving Austin since 2006.
