Designing a home that accommodates multiple generations under one roof requires careful attention to privacy, accessibility, and shared spaces. The 315 m² House T in Meran, South Tyrol achieves this through an L-shaped configuration of two interlocking cuboids that flow into each other while maintaining distinct zones for each generation. The villa’s 990 m³ volume sits on a hillside location surrounded by orchards and vineyards. Architects developing multi-unit residential projects can learn from how architecture firms advance passive house design to ensure that large family homes maintain energy efficiency while serving diverse household needs. This article breaks down the key architectural decisions that make multi-generational villas like House T both functional and elegant.
Hillside Site Strategy and the Floating Volume
House T sits on the outskirts of Merano, a spa town in the Adige Valley. The site slopes toward the valley floor, creating a natural platform for the villa to overlook the surrounding vineyards and orchards. The architects responded to this topography by designing two interlocking cuboids that flow into each other in an L-shape, slightly offset in height to follow the hillside gradient. This configuration creates the illusion that the structure hovers above the green spaces, supported by minimalistic lines, overhanging terraces, and cantilevered staircases. The approach mirrors nature-integrated architecture principles that shape sustainable urban design, where buildings adapt to the land rather than reshaping it.
Reading Contour Lines for Building Placement
Hillside construction requires understanding contour intervals. A site survey with 1-meter intervals reveals the slope gradient and helps determine whether cut-and-fill or elevated foundations are more cost-effective. For the House T site, the 8–12 percent grade allowed the architects to step the two cuboid volumes without deep excavation. Each volume contacts the ground at different elevations, so the upper volume floats while the lower anchors into the slope.
Foundation Systems on Sloping Terrain
Three foundation approaches work for hillside construction. Pad foundations with grade beams distribute point loads where columns meet the slope. Raft foundations spread the load across a wider area but require more excavation on the uphill side. Pile foundations transfer loads to stable soil below the topsoil layer and work best on steep slopes with loose surface material. For the L-shaped configuration, a combination of pad foundations under the structural columns and strip foundations along the retaining walls provides the most efficient load distribution. Drainage at the uphill interface is essential – a perforated drainage pipe wrapped in geotextile fabric along the foundation wall prevents hydrostatic pressure buildup.
| Foundation Type | Best Slope Range | Excavation Required | Relative Cost | Best Use Case |
|---|---|---|---|---|
| Pad + grade beams | 5–15% | Moderate | Moderate | Column-supported structures on gentle slopes |
| Raft/slab on grade | 0–8% | High | High | Uniform loading on stable subgrade |
| Pile foundations | 15–30%+ | Minimal | Very high | Steep slopes with loose or variable soil |
| Stepped strip footings | 8–20% | Moderate | Moderate | Multi-level buildings following contour |
L-Shaped Configuration for Multi-Generational Privacy
The defining challenge of multi-generational housing is balancing togetherness with separation. House T solves this through its L-shaped volume arrangement: each wing houses a different generation’s living quarters, and the corner where the volumes meet contains shared spaces such as the kitchen and dining area. Private spaces and communal places are clearly segregated, allowing each generation to maintain its own daily rhythm. The structural design of such layouts requires careful column placement to support the intersecting volumes at the L-joint, where loads from both wings converge.
Intergenerational Zoning Strategies
Effective zoning in a multi-generational home follows a gradient from public to private. The outermost layer contains shared outdoor spaces – terrace, garden, and entrance. Moving inward, the first interior layer houses communal functions: living room, dining area, and kitchen. The next layer contains semi-private spaces such as study rooms and flexible guest areas. The deepest layer contains private bedrooms, bathrooms, and personal living areas. Each generation’s private zone should have its own entrance from the shared circulation core to eliminate the need to walk through another generation’s space.
Acoustic Separation Between Generations
Sound transmission between generations is a common source of friction in shared homes. The L-shaped configuration naturally provides some acoustic separation because the wings meet only at one corner. Additional measures include: staggered stud walls with resilient channels between the living areas of each wing, acoustic insulation with a minimum of 50 kg/m³ density in all shared partition walls, solid-core doors with perimeter seals at the transition between wings, and carpet or cork flooring in upper-level bedrooms to reduce footstep noise transmission to the level below.
- Each generation gets its own entry sequence: front door, hallway, and private zone without crossing communal spaces.
- Shared spaces sit at the L-joint where both wings converge, accessible from both sides.
- Outdoor circulation paths connect the wings externally, allowing independent access without entering the main house.
- Each private zone includes a compact kitchenette and bathroom so generations can function independently if needed.
- Flexible rooms near the main entrance can serve as home office, guest room, or caregiver space as household needs change.
Cantilevered Staircases and the Illusion of Weightlessness
The cantilevered staircases and overhanging terraces in House T create a visual lightness that contrasts with the solid mass of the hillside. The stairs appear to float without visible support, projecting from the facade like a folded ribbon. This effect is achieved through a hidden central steel stringer that transfers the stair load back to the main structural frame. The design parallels the house-within-a-house concept for maximizing hillside lots, where cantilevered elements allow the building to extend over the slope without disturbing the natural terrain below.
Structural Design of Cantilevered Stairs
A cantilevered stair transfers all its load to the supporting structure at one end only. The cantilever length – the distance from the support wall to the stair’s outer edge – must not exceed the structural depth of the stair multiplied by an appropriate factor. For residential steel cantilever stairs, a span-to-depth ratio of 12:1 is typical. A 3-meter cantilever requires a minimum structural depth of 250 mm in the hidden stringer. The connection point at the supporting wall must be reinforced with a moment-resisting connection cast into the concrete slab or bolted to the steel frame.
Terrace Overhangs and Sun Shading
The overhanging terraces in House T serve double duty as sun-shading devices for the glazing below. The terrace slab extends 1.8–2.4 meters beyond the facade, blocking high-angle summer sun while permitting low-angle winter sun to reach the interior. This strategy reduces peak cooling loads by approximately 20 percent in the Mediterranean alpine climate of South Tyrol. The terrace edge incorporates a concealed gutter system that drains through the supporting columns rather than visible downpipes, maintaining the clean floating appearance.
Vine Leaf Perforations and Agricultural Context
One of the most distinctive features of House T is the playful perforation pattern on the east facade, where vine leaf shapes pierce the surface in front of the entrance area. This detail connects the building to the local agricultural traditions of the Merano region, where viticulture has shaped the landscape for centuries. The perforations serve as a decorative screen that filters light, casts shifting shadow patterns throughout the day, and provides privacy to the entrance without blocking ventilation. The gesture reflects principles found in cottage house design traditions that prioritize character and connection to place.
Perforated Facade Design Parameters
A perforated facade screen must balance three factors: openness ratio, structural stability, and shadow quality. The openness ratio – the percentage of the surface that is open versus solid – determines how much light and air passes through. A 30–40 percent openness ratio maintains privacy while allowing adequate daylight transmission. The leaf-shaped perforations in House T use rounded edges to reduce stress concentrations in the panel material. For metal panels, laser cutting achieves the cleanest edge finish with minimal heat distortion. For concrete or cement-board screens, water-jet cutting produces precise shapes without the micro-cracking that can occur with mechanical cutting.
| Perforation Method | Min. Feature Size | Edge Quality | Material Thickness Range | Relative Cost per m² |
|---|---|---|---|---|
| Laser cutting | 0.5 mm | Excellent, no burr | 0.5–25 mm (metal) | Moderate–High |
| Water-jet cutting | 1.0 mm | Excellent, cold process | 0.5–150 mm (any) | High |
| CNC routing | 3.0 mm | Good, may need sanding | 6–50 mm (wood/composite) | Moderate |
| Punch press (perforated metal) | ≥ 3.0 mm | Moderate, slight burring | 0.5–3 mm (metal) | Low–Moderate |
| Cast-in-place formwork | 10 mm | Fair, textured finish | 50–150 mm (concrete) | High (custom formwork) |
Interior Material Contrast and Lighting Design
The interior of House T presents a deliberate contrast with its exterior. The building’s rationalist, austere exterior gives way to a bright, comfortable interior where soft materials, oak wood, and intelligent lighting design create a cozy atmosphere. The living area uses an open layout with minimal furniture – chairs and a stove provide the only spatial organization within the large volume. This sparse furnishing strategy allows the architecture itself to define the space. The architectural envelope design process governs how these interior surface treatments interact with the building’s thermal and acoustic performance.
Oak Wood Selection and Application
Oak appears in House T as flooring, wall paneling, and built-in joinery. European oak (Quercus robur) offers a Janka hardness rating of 4,800 N, making it suitable for high-traffic residential areas. The wood is finished with a hard-wax oil that penetrates the surface rather than forming a film layer, preserving the tactile quality of the natural grain. For radiant heated floors, the oak must be acclimated to a moisture content of 7–9 percent before installation, and the boards should be quarter-sawn to minimize dimensional movement with seasonal humidity changes.
Intelligent Lighting Zones
The lighting design in House T uses multiple zones controlled independently to adapt to different times of day and activities. A warm 2700K color temperature in the living areas supports relaxation in the evening, while 3500K in the kitchen provides task-level clarity. Indirect cove lighting along the ceiling perimeter washes the walls with soft light, eliminating harsh shadows. The dining area uses a single pendant fixture as a focal point, while the private zones rely on recessed downlights with adjustable beam angles. Motion sensors in circulation areas reduce energy consumption by automatically dimming lights when spaces are unoccupied.
House T achieves its KlimaHouse B certification through the cumulative effect of these design strategies. The south-facing opening captures passive solar gain, which the high-mass concrete floor slab stores and releases slowly through the evening. The overhanging terraces provide shading calibrated to the 46.6°N latitude. The perforated screen filters light before it reaches the building envelope. Each architectural move serves both aesthetic and performance goals simultaneously. For homeowners planning similar projects, the Boxwood House approach to residential architecture demonstrates how controlled proportions, material consistency, and site responsiveness scale across villa-sized projects. The result is a home where multiple generations live together not by compromising on comfort but by sharing thoughtfully designed spaces that respect each resident’s independence.