Small residential projects demand smart structural choices that maximize space without inflating costs. The 100-square-meter house in Tabacundo, Ecuador demonstrates how combining two distinct structural systems within one compact footprint can solve both functional and spatial challenges. One system uses lightweight metal trusses repurposed from temporary tent structures, while the other relies on load-bearing brick walls that serve as both structure and enclosure. For architects and builders working in warm climates, a passive house design approach for warm climates shows how thermal mass, shading, and natural ventilation reduce mechanical cooling requirements even in buildings with mixed structural materials.
Dual Structural Systems in Compact Residential Design
Using two structural systems in one house might sound excessive for a 100-square-meter project, but the approach solves a specific design problem: how to create a light, open living zone alongside a compact, service-oriented zone within a single rectangular footprint. The front of the house, oriented toward the valley view, uses a recycled metal truss system that supports large glass panels and an open floor plan. The rear section relies on structural brick masonry that provides privacy, thermal mass, and enclosure for the bathrooms and kitchen.
Reusing Existing Metal Trusses
The clients had preserved metal trusses previously used to construct temporary tents. Rather than discarding them, the architects designed the entire light structure around these existing components. This decision reduced material costs and embodied carbon while imposing a clear structural rhythm on the open living space. The trusses span the width of the front section, supporting a roof that angles upward toward the view. The reuse strategy saved an estimated 30 to 40 percent of the steel cost compared to purchasing new structural members.
Structural Brick Walls as Enclosure and Support
The brick walls at the rear of the house serve double duty. They carry the roof load from the pitched ceiling above the private zone, and they form the finished interior surface for the bathrooms and kitchen. This eliminates the need for separate structural framing and interior finish materials. The brick mass also moderates indoor temperatures by absorbing heat during the day and releasing it slowly at night, a passive strategy particularly effective in Ecuador’s highland climate where daytime temperatures can swing by 15 degrees Celsius.
Zoning a Small Floor Plan by Material and Function
The rectangular plan divides cleanly into two distinct material zones. The rear strip is closed and heavy, containing the bathrooms and kitchen behind brick walls. The front zone is open and light, housing two bedrooms, the living room, and the dining room within a metal-framed volume enclosed by a high glass screen. This material zoning reinforces the function of each space without requiring interior walls that would reduce the sense of openness.
| Zone | Structural System | Spaces | Character |
|---|---|---|---|
| Rear (private) | Brick load-bearing walls | Kitchen, bathrooms | Closed, heavy, thermally massive |
| Front (social) | Recycled metal trusses | Living, dining, 2 bedrooms | Open, light, glass-enclosed |
| Entry (transition) | Combined systems | Entrance hall, terrace above | Connecting, elevated view |
Transverse Entry and the Pond as a Divider
The entrance is positioned transversely across the middle of the rectangle, facing a small external pond. This placement separates the social zone on one side from the private zone on the other, creating a clear spatial transition without using doors or hallways. Crossing the entry threshold past the pond gives visitors an immediate orientation: the open living areas lie ahead, while the enclosed service spaces remain behind.
Bedroom Placement in the Open Zone
Both bedrooms sit in the light, glass-fronted section rather than in the brick-closed rear. This placement puts the sleeping areas in direct visual contact with the landscape while keeping the more private bathroom functions behind solid walls. The bedrooms use gypsum and fiber cement boards for the few interior divisions that are needed, keeping the overall weight low and the construction simple.
Butterfly Roof and Ceiling Integration
The roof design is one of the most distinctive features of this house. Rather than using a single roof slope, the architects created two opposing ceiling geometries that meet at the entrance. The private zone above the bathrooms and kitchen has a positive-slope pitched roof that sheds water conventionally. The common zone over the living and dining areas has a negative-slope butterfly roof that channels rainwater to a central collection point. The two ceilings meet at the entry hall, which projects upward as an accessible terrace offering a panoramic view of the valley.
The Attic Play Area Above the Bathrooms
The space above the bathroom strip is not wasted. Because the pitched roof rises in that section, a low-height attic is formed beneath it. The architects conceived this space as a children’s play area or a relaxation loft, accessible from the interior. The low headroom makes it unsuitable for adult-oriented rooms but perfectly adequate for kids or lounging. This use of residual volume demonstrates how dual-pitch roof designs can reclaim square footage that a single flat or shed roof would leave unused.
Greywater Treatment Through Landscape Design
The external pond visible at the house entry is not purely decorative. It functions as a greywater treatment system that processes wastewater from the kitchen and bathroom sinks. Aquatic plants growing in the pond absorb nutrients and filter contaminants, allowing the treated water to support the surrounding farmland irrigation. This closed-loop approach is particularly relevant in dry landscapes that rely on irrigation for agriculture, like the Tanda region near Quito.
- Wastewater from the bathroom and kitchen flows into the pond
- Aquatic plant roots filter solids and absorb dissolved nutrients
- Natural biological processes break down organic matter
- Treated water supports irrigation for surrounding crops
- The pond becomes a visual amenity rather than a hidden utility
Wetland Filtration in Residential Design
Small-scale constructed wetlands like this pond filter system require careful sizing to match household output. For a 100-square-meter house, a treatment pond of roughly 5 to 10 square meters with a depth of 0.6 to 1 meter provides adequate retention time for biological treatment. The aquatic plant species must be selected for local climate conditions and nutrient uptake rates. In Ecuador, native species such as water hyacinth and duckweed are common choices for household-scale systems.
Integration With the Dry Landscape
The Tanda region has a naturally dry landscape that has been modified through irrigation to support farming. The greywater pond fits into this modified ecosystem by returning treated water to the irrigation cycle. This approach avoids the need for a separate septic system and reduces the freshwater demand for crop watering. The pond surface also contributes to passive cooling through evaporation, lowering the ambient temperature around the entry by an estimated 2 to 3 degrees Celsius on hot afternoons.
Glass Facade Design for Natural Light and Views
The main facade facing the valley is a high glass screen that extends across the full width of the open living zone. This glazing strategy puts the interior spaces in direct visual connection with the landscape while flooding the rooms with natural daylight. The glass screen faces the Algarrobo tree and the panoramic valley view, making the outdoor landscape the primary decoration of the living space.
Wood Deck as an Intermediate Zone
A wood deck wraps around the entire glass facade, creating an intermediate zone between interior and exterior. The deck extends the living space outdoors and provides a buffer that reduces heat transfer through the glass. During warm hours, the deck offers shaded seating under the roof overhang. During rain, it functions as a covered walkway connecting different parts of the house. The wood material is warm underfoot and contrasts visually with the glass and metal above.
Minimal Interior Partitions for Open Flow
Inside the metal-framed section, gypsum and fiber cement boards provide the few interior divisions needed. These light materials are simple to install, easy to modify, and cost less than masonry partitions. The minimal approach to interior walls preserves the sense of spaciousness within the 100-square-meter footprint and allows daylight from the glass facade to reach deep into the bedrooms and dining area.
Material Selection for Warm-Climate Performance
Every material in this house was chosen with the local highland climate in mind. The brick walls provide thermal mass to stabilize indoor temperatures. The metal roof structure reflects solar radiation and supports the butterfly roof that channels rainwater. The wood deck offers a comfortable outdoor surface that does not absorb as much heat as stone or concrete. The glass facade, while extensive, is shaded by the roof overhang during the hottest part of the day.
| Material | Climate Function | Location in House |
|---|---|---|
| Structural brick | Thermal mass, heat absorption | Rear walls, bathroom enclosure |
| Recycled metal trusses | Lightweight framing, heat reflection | Front roof structure |
| Glass screen | Daylight penetration, views | Main facade |
| Wood deck | Thermal buffer, comfortable surface | Surrounding facade |
| Gypsum/fiber cement | Lightweight interior divisions | Bedroom partitions |
| Aquatic plants | Water filtration, evaporative cooling | External pond |
The success of this project lies in how each material serves multiple purposes. The brick walls are structure and thermal mass. The metal trusses are structure and recycled content. The pond is water treatment and visual amenity. For projects in similar warm, dry climates, combining dual structural systems with passive strategies like greywater treatment and thermal mass can deliver a comfortable small home without relying on mechanical air conditioning.