Central Courtyards and Split-Level Planning in Compact Urban Housing

Dense cities demand housing strategies that make every square foot count. Urban infill parcels, especially those wedged between existing buildings, present a distinct set of constraints: restricted light access, limited ventilation paths, and zero room for wasteful circulation. The HS House in Ahmedabad, India, built between 2017 and 2020 by the firm Saransh, shows how the modern approach to compact residential design can turn severe site limitations into architectural strengths. At 3,600 square feet built on a 1,350-square-foot site, the house achieves three bedrooms, a kitchen and dining level, a basement for future development, multiple terraces, and a central garden. The ratios alone command attention: the built area is 2.67 times the site area. This article unpacks the specific strategies that made that density possible.

The Challenge of Tight Urban Sites

HS House shares party walls on both sides. The neighboring structures remain untouched. The design team could only work with the two short facades for light intake and cross-ventilation. This is a common scenario in dense urban blocks across South Asia, the Middle East, and increasingly in European and North American infill districts. Window placement and opening strategy on constrained elevations becomes the single most important initial decision. On the HS House site, the front face measures roughly 22 feet wide. The rear face is similar. The long side walls, each about 60 feet, are fully blind.

Shared Walls and Restricted Access

The implications of a zero-setback, shared-wall condition reach beyond light and air. Key constraints include:

• No windows on side elevations. Every habitable room must draw light from the front, rear, or an internal void.
• Structural isolation. Demolition of the old structure and construction of the new one must avoid damage to the adjacent buildings. Vibration control and waterproofing at the party wall interface become critical.
• Service routing. Plumbing and electrical risers must fit within the site boundary. Lateral runs to adjacent properties are not possible.
• Construction logistics. Material delivery and crane access are limited to the single street-facing elevation.

Saransh addressed the structural constraint by using precast concrete elements for the ground floor and in-situ casting for upper floors. This hybrid approach minimized wet work on site and reduced the time the shared walls were exposed to vibration from formwork and pouring.

The Central Courtyard as a Passive Climate Strategy

With both long sides blocked, the design team inserted a large central court cut through the entire depth of the house. This void does two things: it brings daylight into every floor level, and it creates a vertical air shaft for natural ventilation. The court is the organizing element of the plan. Every room opens onto it either directly or through a corridor. The passive house principles articulated by the Passive House Network emphasize airtight construction and controlled mechanical ventilation, but in hot-humid climates like Ahmedabad, a well-designed thermal chimney can reduce mechanical load substantially. HS House uses the courtyard as exactly that kind of passive device.

How the Glass Box Creates Natural Airflow

Above the central court sits a glass box that acts as a hot-air attractor. The sequence works like this:

1. Sunlight heats the air inside the courtyard through the glass roof.
2. Warm air rises naturally, drawn upward by the stack effect.
3. The rising air pulls cooler air from the ground-floor garden and from the front and rear openings into the courtyard at lower levels.
4. Small openings at the top of both side walls let the heated air escape, completing the cycle.

The system requires no fans, no ducts, and no energy input. In monsoon season, the glass roof keeps rain out while still allowing convection. In cooler months, operable sections of the glass can be opened to modulate airflow. This single architectural move reduces the cooling load across all three upper floors.

Split-Level Planning for Maximum Space Efficiency

Rather than stacking full-height floors, Saransh divided the house into split levels. The front of the building sits half a story lower than the back. This technique, seen in showcase homes that test real-world spatial efficiency, allows more rooms to fit within the same envelope by shifting floor plates vertically rather than expanding horizontally. The split-level arrangement also breaks up the vertical travel distance: a half-flight of stairs connects adjacent levels instead of a full-flight, which reduces the perceived height and makes vertical movement feel more compact.

The level-by-level breakdown:

• Basement (-1 level). Left unfinished for future development. Currently used for storage and mechanical equipment.
• Ground floor (level 1). Gathering area with a small back garden and the central court garden. This is the main entry point.
• Upper ground (level 1.5). Kitchen and dining room with a large outdoor balcony on the front facade. The half-level offset from the ground floor creates visual separation between the public entry zone and the cooking/eating zone.
• First floor (level 2). Bedroom with attached bathroom.
• Second floor (level 3). Bedroom with attached bathroom.
• Third floor (level 4). Bedroom with attached bathroom.
• Top terrace (level 4.5). Lower terrace used as an additional gathering space. Upper terrace on the rear end used as a service terrace for mechanical equipment and drying.

A small elevator runs through all levels for the elderly occupants. The elevator shaft was placed adjacent to the central court, which means it does not block light to any room and does not consume premium perimeter floor area.

Exposed Concrete and Minimal Materiality

The material palette is deliberately restricted. Exposed concrete dominates every surface. The material choices in the R House project show how exposed thermal mass can stabilize interior temperatures, and HS House takes a similar approach. Concrete absorbs heat during the day and releases it overnight, smoothing temperature swings. But the concrete in HS House is not uniform. The design team specified two distinct treatments to differentiate the base of the building from the upper levels.

Precast Panels and Cost Efficiency

On the ground floor, the exposed concrete contains black pigment and is cast using wooden strips to create a textured finish. This was executed through precast concrete panels rather than in-situ pouring. The decision had three practical benefits:

• Cost reduction. Precast panels are fabricated off-site under controlled conditions, which reduces labor costs and formwork waste.
• Minimal wood use. The wooden strip texture is cast from a single reusable mold. An in-situ solution would have required single-use formwork timber for each pour.
• Faster installation. Panels were lifted into place in a matter of days rather than weeks of sequential pouring and curing.

The horizontal panel lines, combined with the darker pigmented finish, give the ground floor a heavy, grounded appearance. Above the ground floor, the concrete was cast in-situ with a natural light grey shade. The contrast between the dark textured base and the smooth light upper volume creates a clear visual hierarchy. Each bedroom has a different pattern cast into the concrete wall, some with grooves inlaid with brass. These variations cost almost nothing in material terms but give each room a distinct identity.

Circulation and Vertical Experience

The staircase is the primary sculptural element in the house. It connects two separate concrete blocks through the central void. The Everhart passive house remodel demonstrates how careful detailing of transitions between zones reduces wasted space, and the HS House staircase applies that logic to vertical circulation. The structure uses a metal framework sandwiched by sheet metal. A thick handrail acts as the primary beam, suspending the staircase from above. Wooden treads sit on top of the black metal structure, adding a warm tactile surface for barefoot use.

Flooring materials reinforce the hierarchy of movement and pause zones:

• Kota stone is used throughout public areas in multiple laying patterns. Running bond in corridors signals movement. Herringbone or square patterns in landings and courtyard edges signal places to stop.
• Wood flooring is reserved for the bedrooms and private spaces, where thermal comfort and acoustic absorption matter most.
• Black metal accents appear in window frames, door handles, balustrades, and partition frames, creating a consistent visual thread that ties the split levels together.

The elevator shaft, staircase, and courtyard are stacked in a vertical core that occupies less than 15 percent of the total floor area. Every other square foot is usable living space. There are no long corridors, no wasted transition zones, and no double-loaded hallways that consume the center of the plan.

Replicable Principles for Urban Infill Housing

The HS House is a single project on a specific site in Ahmedabad, but the strategies it employs transfer to a wide range of urban infill conditions. The ultra-low-carbon housing lessons documented in the Vienna House project in Vancouver confirm that density, material efficiency, and passive environmental control are mutually reinforcing goals. Split-level planning can be adapted to any site with at least two street-facing exposures or a roof capable of housing a skylight or monitor. Precast concrete with pigment and texture costs less than stone cladding or ceramic facade systems and delivers equivalent visual heft. The courtyard-as-thermal-chimney works in any climate with a diurnal temperature swing of at least 8 degrees C; for cooler climates, the same void can be glazed and used as a solar collector in winter.

The HS House achieves a floor-area ratio of 2.67 on a 1350-square-foot site without relying on deep floor plates, mechanical ventilation, or expensive materials. For architects and developers working on tight urban parcels, the project supplies a tested set of moves: cut a void through the center, offset the floor levels by half-stories, express the concrete structure as finish, and treat circulation as the spine rather than the leftover space. Those four decisions delivered a three-bedroom family home with a garden, a balcony, two terraces, and no dark rooms.