written by:
photos by:
January 15, 2009
Originally published in Around the World
Gregory Katz proves that three times is a charm with his trio of concrete homes, which challenge the status quo in this quiet Johannesburg suburb.
Gregory and Caryn Katz are dwarfed beneath the cantilevered concrete overhang, which houses the bedroom on the upper level. The stackable glass doors that run beneath allow the house to open completely to the yard and swimming pool, soften the severity of
Gregory and Caryn Katz are dwarfed beneath the cantilevered concrete overhang, which houses the bedroom on the upper level. The stackable glass doors that run beneath allow the house to open completely to the yard and swimming pool, soften the severity of the concrete, and blur the boundary between indoors and out.
Photo by 
1 / 10
Inspired by an old technique that Le Corbusier experimented with in the 1930s, Gregory has imprinted Lot Four Two Four’s name on the exterior wall at the entrance, using laser-cut Perspex on concrete.
Inspired by an old technique that Le Corbusier experimented with in the 1930s, Gregory has imprinted Lot Four Two Four’s name on the exterior wall at the entrance, using laser-cut Perspex on concrete.
Photo by 
2 / 10
The shared service at the back of each unit allows for easy access to the garage and enabled Gregory to maximize unobstructed views at the front of each of the three structures.
The shared service at the back of each unit allows for easy access to the garage and enabled Gregory to maximize unobstructed views at the front of each of the three structures.
Photo by 
3 / 10
Modern kitchen with freestanding staircase
The freestanding staircase was built three times before Gregory deemed it structurally sound—a tribute to the architect’s tenacity. The high-tech end result was achieved using small custom-made plastic reinforcing fibers. The galley-style kitchen with its bold use of color was Caryn’s choice. She fell in love with the name of a paint swatch called Canary Yellow and then left it to Gregory to fine-tune the exact hue.
Photo by 
4 / 10
Caryn was thrilled to discover that all her personal details look spectacular when offset against the solemnity of concrete. In profile, the freestanding staircase is the most outstanding design accent.
Caryn was thrilled to discover that all her personal details look spectacular when offset against the solemnity of concrete. In profile, the freestanding staircase is the most outstanding design accent.
Photo by 
5 / 10
With Gregory and Caryn both working from home, it was crucial that their office (a communal space located off the landing upstairs) accommodate separateness of space and privacy.
With Gregory and Caryn both working from home, it was crucial that their office (a communal space located off the landing upstairs) accommodate separateness of space and privacy.
Photo by 
6 / 10
The shower-and-bath-in-one allows for the open feel of the house to translate within the bathroom. Simple concrete slabs function as countertops with inexpensive tiles laid floor to ceiling.
The shower-and-bath-in-one allows for the open feel of the house to translate within the bathroom. Simple concrete slabs function as countertops with inexpensive tiles laid floor to ceiling.
Photo by 
7 / 10
Gregory’s love affair with concrete is evinced by his distinct lack of embellishment, particularly on the exterior.
Gregory’s love affair with concrete is evinced by his distinct lack of embellishment, particularly on the exterior.
Photo by 
8 / 10
Cognizant of concrete’s excessive greenhouse gas emissions, Gregory built with the future in mind: The modular structure of his home could just as easily accommodate the demands of a nursery, restaurant, or office, as suggested by the various seating and
Cognizant of concrete’s excessive greenhouse gas emissions, Gregory built with the future in mind: The modular structure of his home could just as easily accommodate the demands of a nursery, restaurant, or office, as suggested by the various seating and dining arrangements situated throughout the house, particularly in the dining and living area. The space is outfitted with an Eames chair and an unfinished wood shelving unit and dining table. The room opens to the yard and pool, enhancing the room’s circulation to the outdoors.
Photo by 
9 / 10
The only decorative flourishes are those occuring in the interior, like the gentle arc of  a Castiglioni’s Arco lamp visible through a window.
The only decorative flourishes are those occuring in the interior, like the gentle arc of a Castiglioni’s Arco lamp visible through a window.
Photo by 
10 / 10
Gregory and Caryn Katz are dwarfed beneath the cantilevered concrete overhang, which houses the bedroom on the upper level. The stackable glass doors that run beneath allow the house to open completely to the yard and swimming pool, soften the severity of
Gregory and Caryn Katz are dwarfed beneath the cantilevered concrete overhang, which houses the bedroom on the upper level. The stackable glass doors that run beneath allow the house to open completely to the yard and swimming pool, soften the severity of the concrete, and blur the boundary between indoors and out.
Project 
Katz Residence
Architect 

"I’ve never understood the distinction between domestic and commercial architecture,” says South African architect Gregory Katz. “A lot of what I do is an attempt to use engineering materials in a domestic setting in a new, clever way.” One of essentially three identical concrete boxes, the Norwood home Gregory moved into months before marrying his actress wife, Caryn, cuts an incongruous but captivating sight in this leafy middle-class suburb of Johannesburg. The trio of houses contrasts with the area’s mishmash of architectural styles, where a glut of security complexes are characterized by cookie-cutter design and little space in between.

The three 3,660-square-foot dwellings at Lot 424 share over a third of an acre and answer a common desire for space, security, shared maintenance, and even a sense of community. Achieving this in an economical fashion wasn’t easy, but for Gregory, who thrives on the research and development side of a design project, it was all part of the process.

“I love the solidity, strength, and neutrality of off-shutter concrete,” says Gregory. “You can build pretty quickly with it, and the absence of fittings and finishes made the economics convincing. It wouldn’t be cost-effective for one house but it is for three,” he explains. Taking just 18 months to build, the units are designed with a shared-access service road that runs down the back of the buildings and, at 20 feet wide, is big enough to drive cars down and provide off-street parking for visitors. “Each unit is designed so that the more open side of the house looks onto the private sides of the neighboring houses,” explains Gregory. The slope of the ground facilitates this too, with each unit stepping down a bit so that none of the windows correlate.

Gregory’s ability to exploit concrete’s strength is visible in his own home, a huge expanse that feels light and spacious thanks to the absence of a single load-bearing wall. A large aperture of stack-able glazed doors softens the divide between indoors and outdoors, and the freestanding staircase and cantilevered bedroom keep the path of light and space dynamic. Upstairs, the openness continues in the main bedroom, spare bedroom, and home office where Gregory bases his practice. The modular design allows the other two units to utilize the office space for a third bedroom and study. “I’m all for modular design; it’s easy to manipulate and control, and the spin is that it allows tremendous flexibility. So the house is designed to accommodate the demands of a nursery, restaurant, or office in the future. I believe that if you put all this energy into a building, it has to be around for a long time.”

But it took a while for the developer to get the concept. “It’s an incredibly simple box, and so initially, it was difficult to convince the developer that we could surpass these connotations and make concrete ‘warm and homey,’” Gregory says. “I appreciate the super-slick minimalist look, but it’s hard to get right in this country, and I don’t see the point in doing something if you can’t do it properly.”

Studying architecture at Columbia University in New York and working for Daniel Libeskind in Los Angeles has given Gregory some perspective on this. “[Libeskind] taught me the value of experimentation. Where architecture is most often concerned with moral decisions, Daniel is unable to be anything but playful and courageous.” Another influence is maverick architect Zvi Hecker, with whom Gregory worked during a gap year in Tel Aviv and Berlin. “His experimentalism with materials and his insistence on not settling for what’s available, but rather reinterpreting it, has set me in good stead coming back to South Africa.”

For Gregory, Johannesburg is a great place to be an architect. Its origins as a swashbuckling gold-mining city where fortunes were quickly made and lost resonates even now, most notably in its architectural landscape where developers are all-powerful, and buildings go up and come down with little regard for longevity or the preservation of architectural value. “It’s an exciting place to be as there’s much to be done, but it’s not for the fainthearted,” says Gregory, who started his own architectural practice four years ago—three years after returning to South Africa.

“You have to work within what is achievable in this country. I tend to work closely with the builders, which eases the process. In fact, with this house, the builder ate most of the cost of the experimentation on the staircase, as he was just as passionate about getting it right.” After three attempts, strength-tested in situ each time, Gregory is particularly pleased with the high-tech result, achieved using a composite system of welded steel L-profiles, expanded mesh, and polymer fibers in the concrete.

It was a similar journey with the concrete finishes, starting with the boundary wall, for which they used heavy-grain timber as shutters so that the resulting molded concrete retains the impression of the timber grain. They also used laser-cut Perspex to imprint text on walls, inspired by an old technique that Le Corbusier used in the 1930s. “There’s an alchemy to concrete that allows it to take on many guises at very little cost,” says Gregory. The concrete staircase is pigmented black, a durable choice for a high-traffic area that can withstand nicks and scratches, and the slab on the terrace has been ground to expose the black flecks of Johannesburg granite used as an aggregate. Concrete countertops in the kitchen have been finished simply with an invisible sealant while the windowsills in the bedrooms form deep slabs to resemble floating shelves.

The house has also been designed to be thermally efficient with the overhang on the terrace carefully calibrated to avoid the summer sun but capitalize on it in winter, when the sun is lower and the light comes through the huge glass doors in the living area. “Our Highveld winters are good because they’re sunny, so the concrete absorbs heat during the day and gives it off at night,” notes Gregory. The radiant heating is also embedded directly into the slab of concrete. In summer the big openings and cross ventilation ensure a thorough flow of air throughout the house.

A self-confessed minimalist, Gregory is the first to admit that the architecture can’t stand alone, and that the stereotypically masculine order of the house needs a feminine counterpoint. “There’s a lot of clutter around with Caryn,” he quips. “But I love it. This place needs to be lived in and she makes it happen. The color is all her,” he says, pointing to the bright yellow kitchen cabinets. “Gregory enjoys the calculus whereas I’m more spontaneous and don’t mind living with the consequences of imperfection,” says Caryn. “But I trust him. I initially chose a paint swatch called Canary Yellow, which admittedly I loved because of the name. Gregory then agonized over the final color choice, but eventually he settled on this citrus hue and of course it’s perfect.”

They both marvel at how grown-up the house feels in comparison to their previous Art Deco apartment. “At first I thought I was moving into a mission statement for Gregory’s head, which was a little intimidating,” Caryn muses. “It’s taken a while to get used to it, but I’m surprised at how quickly I’ve managed to make the space my own. What I hadn’t anticipated was how the house makes all my little personal details like photos and tablecloths look quite spectacular. In our previous space they just blended in, but here they stand out. I really like that.” And when you consider the marital harmony this must afford, it’s the design’s most impressive accomplishment to date.

Join the Discussion

Loading comments...

Latest Articles

45 dva 2270 persp1 cmyk 0
The prospect of retirement doesn’t just signal the end of a career; it offers the chance to recalibrate and re-prioritize in life.
July 25, 2016
18
You don’t have to choose between sustainable energy and curb appeal.
July 19, 2016
jakemagnus queensland 1
Each week, we tap into Dwell's Instagram community to bring you the most captivating design and architecture shots of the week.
July 06, 2016
content delzresidence 013 1
Each week, we tap into Dwell's Instagram community to bring you the most captivating design and architecture shots of the week.
June 29, 2016
abc malacari marwick stair 01 0
A simple set of stairs is a remodel’s backbone.
June 28, 2016
Design Award of Excellence winner Mellon Square.
Docomomo US announces the winners of this year's Modernism in America Awards. Each project showcases exemplary modern restoration techniques, practices, and ideas.
June 27, 2016
monogram dwell sf 039 1
After last year’s collaboration, we were excited to team up with Monogram again for the 2016 Monogram Modern Home Tour.
June 27, 2016
switch over chicago smart renovation penthouse deck smar green ball lamps quinze milan lounge furniture garapa hardwood
A strategic rewire enhances a spec house’s gut renovation.
June 26, 2016
young guns 2016 emerging talent coralie gourguechon treviso italy cphotos by coralie gourguechon co produced by isdat planche anatomique de haut parleur1
Coralie Gourguechon's paper objects will make you see technology in a whole new way.
June 26, 2016
green machine smart home aspen colorado facade yard bocci deck patio savant
Smart technology helps a house in Aspen, Colorado, stay on its sustainable course.
June 25, 2016
Compact Aglol 11 television plastic brionvega.
The aesthetic appeal of personal electronics has long fueled consumer interest. A new industrial design book celebrates devices that broke the mold.
June 25, 2016
modern backyard deck ipe wood
An angled deck transforms a backyard in Menlo Park, California, into a welcoming gathering spot.
June 24, 2016
dscf5485 1
Today, we kicked off this year’s annual Dwell on Design at the LA Convention Center, which will continue through Sunday, June 26th. Though we’ve been hosting this extensive event for years, this time around is particularly special.
June 24, 2016
under the radar renovation napa
Two designers restore a low-slung midcentury gem in Napa, California, by an unsung Bay Area modernist.
June 24, 2016
Exterior of Huneeus/Sugar Bowl Home.
San Francisco–based designer Maca Huneeus created her family’s weekend retreat near Lake Tahoe with a relaxed, sophisticated sensibility.
June 24, 2016
light and shadow bathroom walnut storage units corian counter vola faucet
A Toronto couple remodel their home with a special emphasis on a spacious kitchen and a material-rich bathroom.
June 24, 2016
Affordable home in Kansas City living room
In Kansas City, an architecture studio designs an adaptable house for a musician on a budget.
June 23, 2016
modern lycabettus penthouse apartment oak vertical slats office
By straightening angles, installing windows, and adding vertical accents, architect Aaron Ritenour brought light and order to an irregularly shaped apartment in the heart of Athens, Greece.
June 23, 2016
kitchen confidential tiles custom cabinetry oak veneer timber house
A modest kitchen addition to a couple’s cottage outside of Brisbane proves that one 376-square-foot room can revive an entire home.
June 23, 2016
feldman architecture 0
Each week, we tap into Dwell's Instagram community to bring you the most captivating design and architecture shots of the week.
June 22, 2016
Blackened timber Dutch home
A modern dwelling replaces a fallen farmhouse.
June 22, 2016
hillcrest house interior kitchen 3
Seeking an escape from bustling city life, a Manhattan couple embarks on a renovation in the verdant Hudson Valley.
June 22, 2016
angular
Atelier Moderno renovated an old industrial building to create a luminous, modern home.
June 21, 2016
San Francisco floating home exterior
Anchored in a small San Francisco canal, this floating home takes its cues from a classic city habitat.
June 21, 2016
modern renovation addition solar powered scotland facade steel balcony
From the bones of a neglected farmstead in rural Scotland emerges a low-impact, solar-powered home that’s all about working with what was already there.
June 21, 2016
up in the air small space new zealand facade corrugated metal cladding
An architect with a taste for unconventional living spaces creates a small house at lofty heights with a starring view.
June 21, 2016
young guns 2016 emerging talent marjan van aubel london cwai ming ng current window
Marjan Van Aubel makes technology a little more natural.
June 21, 2016
urban pastoral brooklyn family home facade steel cypress double
Building on the site of a former one-car garage, an architect creates his family’s home in an evolving neighborhood of Brooklyn.
June 20, 2016
Modern Brooklyn backyard studio with plexiglass skylight, green roof, and cedar cladding facade
In a Brooklyn backyard, an off-duty architect builds a structure that tests his attention to the little things.
June 20, 2016
the outer limits paris prefab home living area vertigo lamp constance guisset gijs bakker strip tablemetal panels
In the suburbs of Paris, an architect with an eco-friendly practice doesn’t let tradition stand in the way of innovation.
June 20, 2016