ZLG Design Guts a 1980s Terrace House and Rebuilds It Around Air, Light, and No Doors

Most renovation projects start with a brief from a client. W39 House started with a couple of architects, Susanne Zeidler and Huat Lim of ZLG Design, deciding to take apart their own home after 27 years of living in it. The house was a typical 1980s Malaysian link terrace: clustered rooms, enclosed corridors, the kind of layout that treats tropical heat as something to seal out rather than something to work with. When their children moved out, the architects saw the opportunity to test a conviction: that a house in Kuala Lumpur's Ampang Jaya can function without a single interior door, without air conditioning, and with a third of its original floor area simply removed.

What makes W39 genuinely interesting is not just the subtraction but the system that replaces it. The architects carved a triple-height void through the center of the house, bridged it with open walkways, and let the existing retaining wall become the main structural and aesthetic feature of the interior. Light mass bricks without cement plaster, recycled metal hardware scavenged from demolished homes, marine plywood slatted screens, and trees planted directly into the floor plane turn a 2,900 square foot terrace into something closer to a vertical garden with sleeping platforms. The house faces east, and every surface has been calibrated to let air move and light enter without overheating.

A Facade of Layers and Salvage

From the street, W39 barely announces itself. Corrugated metal screens layer over a perforated brick base wall, and overhead power lines cross the frame like they do for every other house on the block. The six-bay paneled upper facade is composed of openable marine plywood slatted windows, hinged with vintage hardware recycled from older homes in the area. There is no grand entrance gesture. The house earns its identity from material honesty rather than formal ambition.

At ground level, folding glass doors open from the dining room onto a gravel courtyard with concrete benches, blurring the threshold between house and garden. The site sits across an elevated dead-end road overlooking a valley, giving the otherwise modest frontage an unexpected depth of prospect.

The Central Void as Organizing Principle

The most dramatic intervention is the triple-height atrium that now runs through the core of the house. By removing a full third of the original built-up area, ZLG Design created a vertical shaft that pulls daylight from a large skylight down through the entire section. Concrete columns and exposed timber beams frame the void, while glass-railed bridges connect the upper levels. The effect is less like a renovated terrace and more like a narrow basilica with its nave open to the sky.

This void is not decorative. In a naturally ventilated house with no air conditioning, it functions as a thermal chimney, drawing warm air upward and out while cooler air enters through the perforated brick walls and slatted screens at lower levels. The architects have effectively turned the absence of floor area into the engine that makes the remaining spaces habitable year-round in a tropical climate.

Perforated Brick and the Quality of Light

Light mass bricks, used without cement plastering, form perforated screen walls throughout the house. These are locally available, inexpensive materials chosen not for visual effect alone but for performance: they filter daylight into dappled patterns that shift across polished concrete floors throughout the day, and they allow cross-ventilation without compromising privacy. The white spiral staircase wrapped in perforated brick reads almost as a sculptural lantern, pulling light deep into what would otherwise be the darkest part of the section.

The architects accept that these unplastered surfaces will weather, stain, and develop patina over time. That acceptance is not incidental. It is the philosophical core of the project: materials should show their age, and a building's true character emerges through its relationship with climate and time rather than through resistance to them.

Living Without Walls or Doors

There is not a single door in W39 other than the entrance gate. All internal walls, including those around bathrooms, have been removed. The second floor divides two sleeping areas using nothing more than curtains. A hammock hangs beside a perforated brick wall in the double-height living zone. The lower ground floor functions as a separate sleeping and living space with its own front garden and entrance, intended for visiting children or friends. The entire house operates on the principle that enclosure is optional when air and light flow freely.

Rattan furniture, timber slatted ceilings, and white shelving systems define zones without defining walls. The kitchen island sits partially inside and partially out, dissolving the conventional distinction between cooking space and courtyard. It is a radical proposition for most contexts, but for two architects living alone in a tropical climate, it is also a practical one.

Trees Inside, Plants Climbing

A tree grows in the entry foyer, planted directly into a bed at the foot of a cantilevered concrete staircase. Creeping plants have been introduced to the retaining wall with the explicit intention that they will colonize the surface over years. Gravel courtyards with young trees and potted plants punctuate the interior at multiple levels, and planted shelves occupy what might otherwise be dead zones against louvered screen walls.

The planting strategy is inseparable from the ventilation strategy. The courtyards are not ornamental interludes; they are the lungs of the house. As plants grow and the retaining wall greens over, the microclimate within the section will continue to evolve. W39 is designed to become cooler, shadier, and more alive over time, not less.

Material Honesty and Recycled Detail

Bare concrete surfaces, exposed beams, and recycled metal angle frames form the material palette. Metal window and door casings are fitted with vintage hinges salvaged from older houses, a quiet act of preservation embedded in the construction detailing. The dining area sits beneath exposed concrete beams and clerestory windows, with a perforated brick wall admitting soft, filtered light at one side. There is a deliberate roughness to the finishes that aligns with the architects' conviction that weathering is not decay but expression.

Concrete portals frame views through interconnected rooms, each threshold offering a long perspective terminated by either timber beams and warm light or a planted courtyard. The sectional complexity of the house means that almost every position offers a view into at least two other levels, creating an experience of spatial richness within a footprint that remains, at its base, a narrow terrace lot.

Bridges and Mezzanines

The upper levels read as a series of platforms suspended within the central void. Mezzanines with glass balustrades overlook timber storage units below, and link bridges cross the atrium to connect sleeping areas. From above, the stairwell and planted courtyard become a composition of dappled sunlight, foliage, and layered concrete planes. The copper pendant hanging in the double-height living space provides a single point of warmth against the otherwise cool material palette of concrete, brick, and timber.

The stacked concrete block planter wall, tended by one of the architects, doubles as both a vertical garden and a thermal buffer. Every element in W39 carries at least two functional roles, which is what happens when the designers are also the inhabitants and have had decades to observe how their house actually performs.

Plans and Drawings

The floor plans across three levels reveal how internal courtyards and planted areas are distributed not as afterthoughts but as the primary organizing elements around which rooms (or rather, zones) are arranged. The section drawing makes the thermal chimney strategy legible: sloped roofs channel air upward while trees on both sides of the building provide shade at the lower levels. The plans also show just how narrow the terrace lot is, which makes the sense of vertical openness achieved by the central void all the more impressive.

Why This Project Matters

W39 House matters because it demonstrates, in built form, that the Malaysian terrace house is not a dead typology but a latent one. The standard 1980s link terrace was designed around assumptions about privacy, enclosure, and mechanical cooling that are ecologically expensive and experientially limiting. By removing walls, doors, and a third of the floor area, ZLG Design proved that the same structural shell can support a radically different way of living, one governed by natural ventilation, internal planting, and the willingness to let a building weather.

The fact that the architects are also the homeowners is essential context. W39 is not a speculative exercise or a show home. It is a lived-in argument, developed over 27 years of inhabitation and three years of final construction, about what tropical domestic architecture can be when comfort is redefined away from sealed, air-conditioned boxes and toward open, breathing structures that age with grace. In a region where terrace housing constitutes a significant portion of the urban fabric, that argument carries weight well beyond a single house in Ampang Jaya.

W39 House by ZLG Design (Susanne Zeidler, Huat Lim), Ampang Jaya, Malaysia. 2,900 sq ft. Completed 2018. Photography by Lawrence Choo and Lin Ho.

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