An addition is the project that lets you stay on the street you love in a house that finally fits. MASACO Construction designs and builds home and room additions across Dallas: primary suites off the back of a Lakewood Tudor, second stories over ranch houses in Lake Highlands, family room bump-outs in Far North Dallas, and garage conversions in Oak Cliff. We’re a woman-led design-build firm based in Plano, and every addition we take on starts with a 3D model of your existing house so you can see the finished result before we pour a footing.
Why an addition beats moving on Dallas’s older streets.
The neighborhoods people most want to live in were largely built out between the 1920s and the 1990s. Lakewood, the M Streets, Kessler Park, and Casa Linda carry the character of their original builders, and the lots in Preston Hollow, University Park, and Highland Park are hard to replace at any price. The trade-off is that those houses were built for a different way of living: small primary bedrooms, one bathroom per floor, closed kitchens, and no home office.
Adding on solves that without giving up the location, the school zone, or the mature trees. It also tends to hold value in Dallas because buyers in these areas pay for finished square footage on an established block. The catch is that an addition done poorly is obvious from the street. Mismatched brick, an awkward roof plane, or a floor that steps down at the threshold will cost you when you sell. The details below are how we avoid that.
Ground floor or second story: how we decide.
Every addition conversation starts with the same question, and the answer comes from your lot, your structure, and your budget.
A ground-floor addition needs its own foundation, its own roof, and a clean tie-in to the existing exterior wall. It’s the simpler build when you have yard to spare, and it’s the natural choice for a primary suite, a larger kitchen, or a family room off the back. Most houses in Lake Highlands, Far North Dallas, and the newer parts of Preston Hollow sit on lots that can take one.
A second-story addition keeps the footprint and the yard. On a narrow lot in the M Streets or a corner lot in Kessler Park with setbacks on 2 sides, going up may be the only way to gain real square footage. It’s more involved. An engineer has to confirm the existing slab and load-bearing walls can carry a second floor, and often they need reinforcement. The roof comes off, so the sequencing has to be tight, and many families move out for that phase.
We don’t have a default. On the site walk we look at the slab edge, the roof pitch, where the plumbing runs, and how the lot is zoned. If both options are realistic, we model both so you can compare them side by side.
Tying into a slab foundation and an existing roofline.
Most Dallas homes sit on slab-on-grade foundations, and the clay soil under them moves with the seasons. That’s why the foundation detail on an addition matters more here than it does in a lot of other markets. The new slab has to be engineered to move with the old one, or be intentionally isolated from it, so you don’t end up with a crack running across your new floor a few summers later. We bring in a structural engineer on every addition, and the drawings they produce are what the city reviews and what our crews build from.
The roofline is the other place additions go wrong. A new roof plane has to drain correctly, meet the existing roof without creating a dead valley where water and leaves collect, and look like it belongs. On a low-slung 1960s ranch in Casa Linda that might mean continuing the hip roof. On a 1920s Tudor in Lakewood it might mean a steep gable that echoes the front. The 3D model shows you exactly what the new roofline looks like from the street and the backyard before we commit to it.
Matching brick, mortar, and trim on a 1950s to 1990s house.
Dallas is a brick city. The brick on a 1955 house in Lake Highlands or a 1978 house in Far North Dallas has almost certainly been discontinued, and the sun has been working on it for decades. A straight match is rare.
What we do instead is source the closest current run, blend in salvaged brick when we can find it, and dial in the mortar. Mortar color and joint profile change the read of a wall as much as the brick does, and getting them right is most of the battle. Where a true match isn’t realistic, we design the transition on purpose: a change in plane, a trim band, a section of siding or stucco that the original house already uses somewhere. The goal is an addition that reads as intentional, not as a patch.
The same thinking applies to windows, eave depth, and trim profiles. A 1960s house has different proportions than a 1990s house, and we match the one you own.
Zoning, setbacks, and the reviews that add steps.
Before we draw anything, we pull the zoning for your specific address. Dallas residential districts set front, side, and rear setbacks and a maximum lot coverage, and those 2 rules often decide whether the addition goes out the back, off the side, or up. Irregular lots in Oak Cliff and Kessler Park make the survey especially important.
Inside the City of Dallas, permits run through City of Dallas Development Services, and an addition typically carries structural, electrical, plumbing, and mechanical inspections before the final. Highland Park and University Park are separate cities with their own building departments and their own review standards, which we plan for from day one. If your house is in a conservation district, such as parts of the M Streets or Lakewood’s protected blocks, or under a historic overlay, the exterior design goes through an additional review before a building permit is issued. HOAs in Far North Dallas and Preston Hollow often add an architectural review of their own.
None of this should scare you off. It’s paperwork and sequencing, and it’s what we do. We prepare the packets, attend the reviews where needed, and build the review time into your schedule up front instead of discovering it later.
Primary suites, garage conversions, and ADUs.
The 3 additions we’re asked about most:
Primary suite additions. A bedroom, a bathroom with a proper shower and double vanity, and a walk-in closet, usually off the back or side of the house. We design the bathroom layout and closet in 3D so you can walk the space on screen and adjust it before the plumbing is roughed in.
Garage conversions. The slab and roof already exist, which makes this one of the most efficient ways to add a bedroom, office, or in-law suite. It still needs a permit, insulation, HVAC, and usually a new exterior wall where the garage door was, and in some districts the parking you remove has to be replaced.
Accessory dwelling units. Dallas allows ADUs in some areas subject to zoning, lot size, and parking rules that vary by district and have changed over the past few years. We’ll confirm what your address allows before we design anything. Where an ADU is permitted, it can be a backyard cottage, a garage apartment, or a unit above a new detached garage.
How we run an addition from first walk to care guide.
Our process is the same one we use across general construction, sized for an addition. It’s laid out in full on our process page.
- Consultation and site walk. We meet at your home, measure, photograph, and look at the slab, roof, and utilities. We talk openly about budget range and what’s realistic on your lot.
- Design and 3D visualization. We model the addition onto your existing house. You approve the roofline, the exterior transition, and the interior layout before anything is demolished.
- Fixed-scope proposal. One written scope with allowances for finishes, one schedule, one price for the defined work. Changes are written change orders you approve in advance.
- Engineering, permits, and approvals. We coordinate the structural engineer and file with the city, the Park Cities departments, your HOA, or a conservation district as needed.
- Build, with a weekly update. One project manager owns the job. You get a written update with photos every week: what happened, what’s next, and any decision we need from you. We schedule and pass every inspection.
- Walkthrough, punch list, and care guide. We walk the finished addition with you, write down every item, close the list, and hand you a care guide for the finishes we installed.
If the addition is part of a larger renovation of the existing house, we fold it into a whole-home remodel so the two are designed and priced together. And if you’re weighing an addition against starting over, our custom home building page walks through when a teardown makes more sense.
How we price it.
We price additions as fixed-scope proposals, not open-ended estimates. After you approve the 3D design, you receive a line-item scope that covers foundation, framing, roof tie-in, exterior, mechanical, electrical, plumbing, insulation, drywall, and finishes, along with the engineering, permit, and review costs.
Finishes you haven’t selected yet carry allowances, which are stated amounts for tile, plumbing fixtures, flooring, and lighting. Choose within the allowance and the price holds. Choose above it and you pay only the difference, documented in writing. Anything outside the scope, like adding a window or discovering a buried problem when we open a wall, becomes a written change order with a price and a schedule impact that you approve before the work happens. You won’t get an invoice for something you didn’t sign.
Additions across Dallas-Fort Worth.
We build additions throughout Dallas and the surrounding cities from our headquarters in Plano. The permitting rules and housing stock shift from city to city. Plano’s 1980s and 1990s two-stories bring different structural questions than a 1940s bungalow in Oak Cliff, and Fort Worth has its own development department and its own historic districts. Our project managers know the difference. See finished work on our projects page, and for a general contractor to handle the addition alongside other work on the property, start with our general contracting page.
Ready to see what your house could become? Book a consultation and we’ll walk your property, talk through ground-floor versus second-story options, and show you what’s buildable on your lot. Contact MASACO Construction to schedule. Think Massive. Build Smart.
What's included.
- Ground-floor additions tied into the existing slab foundation and roofline
- Second-story additions with structural engineering for the existing walls and slab
- Primary suite additions with bathroom and closet layouts designed in 3D
- Kitchen and family room bump-outs that open up the back of the house
- Garage conversions to bedrooms, offices, or in-law suites
- Accessory dwelling units where Dallas zoning allows them
- Brick, mortar, and trim matching for 1950s to 1990s homes
- Structural engineering, permits, and HOA or conservation-district submittals
- HVAC, electrical, and plumbing extended and sized for the added square footage
- One project manager with weekly written photo updates
How the project runs.
- Consultation and site walk. We meet at your home, walk the lot, and measure the existing footprint. We look at the slab edge, roof pitch, utility locations, and where setbacks and lot coverage will shape the addition. You leave with a realistic read on what's buildable and roughly what it involves.
- Design and 3D visualization. Our design team draws the addition into a model of your existing house so you can see the new roofline, the brick transition, and the interior flow before anything is built. Layout, windows, and finishes get settled here, where changes are cheap.
- Fixed-scope proposal. You receive a line-item scope for the addition with allowances for finishes, a schedule, and one fixed price for the defined work. Anything you add later, like an extra window or upgraded tile, becomes a written change order you approve first.
- Engineering, permits, and approvals. We coordinate the structural engineer's foundation and framing drawings, submit to City of Dallas Development Services or your Park Cities building department, and prepare HOA or conservation-district packets where they apply. You sign where required and we manage the rest.
- Build, walkthrough, and care guide. One project manager runs the job from foundation pour to final paint and sends you a written photo update every week. We schedule and pass each inspection, walk the finished addition with you, close the punch list, and hand over a care guide for the new finishes.
