Addition over $150,000
Austin, Texas
CG&S Design-Build, Austin, Texas
When the owners of this unique Austin home decided they needed to expand their living space, they turned to the same company that had previously remodeled the home — albeit for another owner.
It had only been a few years since CG&S Design-Build had renovated the concrete home for the earlier residents, reorganizing spaces on the first floor — the kitchen, family room and a bathroom — and adding a new master bath.
The new owners, though, decided they wanted to add a new master suite. While the clients and CG&S looked at both expanding out the back of the first floor and adding a second story, the clients much preferred going up, says senior project designer Mark Lind.
“They have a great view of Austin’s downtown skyline and they wanted to preserve that,” Lind says. “It also gives them more privacy and seclusion from the kids downstairs.”
One of the homeowners is a physician who works a lot of nights and then often sleeps during the day. The homeowners decided she would have less noise upstairs than on the same floor as their two young sons. The new second floor includes a master bedroom, bath and closet, along with a rooftop deck and outdoor fireplace.
CG&S worked to blend the two remodels by carrying some elements over to the new addition. For example, the finish on the upstairs cabinetry, as well as the stained MDF-paneled wall on the stairway, echoes the stained walnut trims downstairs. The concrete and glass landing for the stairs mimics the finish on two custom-cast concrete accent pieces from the original project.
“You have two different clients — obviously they bought the house because they liked it and they appreciated the aesthetic, but everyone has their own subtle differences in what kind of aesthetics they liked,” Lind says.
Concrete challenges
Once the clients decided to add a second floor, there were several challenges for CG&S to address. Most notably, building above a flat concrete roof. While concrete has great compression strength, it’s extremely weak in its tensile — bending and flexing — strength.
CG&S didn’t have any architectural drawings of the home that identified where the steel roof supports were located, but did have X-rays of the concrete from the earlier remodel. The engineer the company was working with cautioned the design team that the existing structure probably couldn’t support a second floor.
Instead, the CG&S team designed a structural system of long trusses that bear on the front and rear load-bearing walls on the first floor. That system supports both the new second floor and the deck that surrounds it.
The stairway alsopresented a challenge, with 11 inches of existing first-floor concrete roof to cut through. (Those earlier X-rays turned out to be handy here, too.) After cutting through the concrete, new steel channels helped to hold it together.
“Trying to cut and remove that much concrete without damaging the house, that was a challenge, too,” Lind says.
That stairway, with its open design and minimal materials, was a favorite feature of the award judges. It came about because the clients wanted as basic a look as possible.
“They wanted a thin, minimal railing, so we just went with the cable rail there,” Lind says. “Primarily, when you do open risers like this, where it’s just floating treads, we’ve learned to just beef up the treads, so that determined the basic aesthetic.”
Five-Star green
Both sets of homeowners were interested in making the home a standout green project. In fact, both phases of the remodel earned a Five Star (the highest possible) from the Austin Energy Green Building Program. Austin’s green program was one of the country’s first and has served as a model for many other green building programs across the country.
“One of the challenges we faced was taking a concrete house and trying to make it a green building,” Lind says. “In our climate, it just doesn’t cool off at night. The challenges all really came from this unique structure.”
Before CG&S remodeled the home, it had no insulation in the walls and little in the roof. It also had a series of inefficient jalousie windows — horizontal blades similar to what can be found in the tropics.
The previous owners had installed a 5kW solar array in the first remodel. That was relocated to the roof of the new stair tower in the second phase, but the current owners wanted to go further.
“They weren’t concerned with the ratings for resale or anything like that,” Lind says. “They just wanted to be environmentally responsible, as green as possible.”
CG&S installed LED lights throughout the home, as well as expanding half-pound foam insulation in the walls and ceiling. The company installed a tankless water heater, and zero-VOC paints were used during the project.
The “butterfly” roof also helps meet the homeowners’ green goals, by making it easier to collect rainwater and funnel it to two large downspouts for re-use.
“The owner had suggested that early on, but I was a little leery of doing it that way,” Lind says. “Against everyone’s better judgment, you’re collecting all the rain in the center of the roof and not shedding it on either side.”
However, when he started sketching out the design, Lind decided it worked not only from a green standpoint but from an aesthetic one, helping create the home’s unique look. The roof also extends 8 feet over the east side of the home to provide additional shade.
“Design really should start with the roof,” he says. “That shape kind of set the theme early on. It takes a concrete house, which would seem very heavy, and gives it a lightness.”