Located on the slopes of Mount Galdames lies the municipality of Galdakao, characterised by a markedly rugged topography crossed by the Ibaizabal River, which further downstream forms the Bilbao estuary. In this town in Bizkaia, just over 10 kilometres from Bilbao, the Bilbao-based studio BAT Architecture signs IB House, a semi-detached dwelling conceived as an exploration of the relationship between domestic architecture, landscape and materiality.
The project proposes two independent homes that share the same spatial and constructive strategy, developed around three central ideas: the deep penetration of natural light, visual continuity between levels, and the use of timber as both structural and expressive material.
The house is built on an urban plot of just over one thousand square metres located on Zabalea Street, within an established residential neighbourhood. The site presents an approximate three-metre slope descending towards the south, a condition the project takes advantage of to orient the main spaces towards the valley while freeing the sunniest part of the plot for the garden and outdoor areas.
From the outset, the brief proposed the objective of building two homes that could share the same architectural logic without renouncing the privacy and identity of each. The architects’ response consists of a spatial system that organises the building through vertical voids and bands of light capable of structuring the relationships between the different rooms.
Implantation and relationship with the site
The building is placed on the highest part of the plot, occupying a rectangle of approximately 19 by 13.5 metres that respects the distances from boundaries established by municipal regulations. This position allows the terrain to unfold towards the south through a sequence of landscaped platforms that follow the natural slope of the site.
The outdoor areas are therefore organised as a succession of spaces directly connected with the living areas of the house. The swimming pools are integrated along the axis of these terraces, reinforcing the visual continuity between interior and exterior and expanding the spatial perception of the whole dwelling.
Both pedestrian and vehicular access occur from the north-eastern edge of the plot, ensuring clear routes and independent entrances for each home.
Two homes organised around light
The organisation of the project begins with a simple geometric strategy: two L-shaped volumes that distribute the private spaces evenly across the plot while at the same time defining the outdoor areas associated with each dwelling.
Inside, the project is structured through vertical double-height bands that cut through the built volume. These voids function as true spaces of relationship, visually connecting the different levels and allowing natural light to penetrate deep into the interior of the house.
These openings organise domestic life. Around them are arranged the main rooms —living room, kitchen, dining room and bedrooms— which open to the outside through large openings in the façade.
The natural lighting strategy continues also at the lower level of the building. In the basement, glazed English courtyards allow light to reach the leisure and gathering spaces located on this level, avoiding the feeling of being underground and maintaining the environmental continuity of the whole.
Fragmented volume, domestic scale
From the outside, the house appears as a composition of volumes that reinterpret the traditional domestic scale. The building is fragmented into four pitched-roof bodies surrounding a central flat-roofed volume.
This composition generates a stepped volumetry that dialogues with the topography of the site and reduces the visual presence of the building within the residential landscape. At the same time, the fragmentation allows the bands of light and interior voids to manifest themselves in the external expression of the ensemble.
The envelope is resolved with a continuous cladding of charred larch wood, a choice that gives the building a clear and homogeneous architectural identity. The treatment of the material intensifies the texture of the timber and reinforces the unified reading of the built volume.
Beyond its aesthetic dimension, the choice of timber also responds to environmental and constructive criteria. The structure reduces the environmental impact of the building and connects with a construction tradition deeply rooted in the territory. In addition, industrialised systems based on timber optimise the construction process, reduce the necessary excavation and improve the thermal performance of the whole.
An architecture organised by voids
IB House unfolds across three levels —basement, ground floor and first floor— accommodating a complete domestic programme for each of the homes. The lower level integrates technical spaces, storage and service areas, as well as a shared parking space with capacity for eight vehicles.
The ground floor concentrates the living areas: kitchen, dining room and living room are oriented towards the garden and outdoor spaces, reinforcing the direct relationship between interior and landscape. On the upper floor are located the bedrooms and main suites, organised around the double-height spaces that structure the dwelling.
Architecture here is built from the relationship between solids and voids. It is the open spaces, crossed by light, that organise the domestic experience and establish the connection between the interior of the house and the surrounding landscape.
In IB House, architecture is quietly organised around light, timber and territory, constructing a spatial system where landscape, structure and daily life become part of the same continuity
Furniture
Custom kitchens: Key Cucine. Countertops: Marmolería Izarri. Kitchen glazed doors: Barausse.
Beige stool: Alo H65 Ondarreta by Saltoki Home. Grey stools: Rely Hee Welling &Tradition by Saltoki Home. Sofa: Beam System with Chaise Longue Tela Perbacco 13E417 by Saltoki Home. Lighting: Secto Design and Nexia, Marset BCN and Aromas del Campo. Outdoor lamps: Santa & Cole by Susaeta Iluminación. Outdoor armchairs: Kettal. Living room armchairs: Cassina by Saltoki Home. Dining table: Novamobili. Dining chairs: Hola Cassina by Saltoki Home.
Project: IB House.
Location: Galdakao, Bizkaia. País Vasco.
Built area: 910 m²
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Completed: 2025.
Architecture studio: BAT Architecture.
Lead architects: Peru Cañada, Xabier Arranz.
Interior design: BAT Home Design + Saltoki Home.
Photography: Aitor Estévez . BAT Architecture.
Main contractor: BDT Bilbao Design Team.
Mechanical engineering: Efiner (soluciones energéticas)
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Construction: Excavaciones Loroño, Hormitec.
Supervision: BDT Bilbao Design Team
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Materials: CLT
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Interior contractor: BDT Bilbao Design Team
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Landscape design: Espacios Verdes del Norte
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Civil works and urbanisation: Comoser Obras
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Lighting design: TAO Iluminación.
Electrical engineering: Teknolux.
BAT Architecture
In the city of Bilbao —a place that has learned to reinvent itself from its own industrial matter and its watery horizon— BAT – Bilbao Architecture Team emerges as a contemporary and sensitive response to the way of making architecture. Founded in 2012 by architects Peru Cañada and Xabier Arranz, the studio defines itself as a transdisciplinary practice that integrates architecture, urbanism, interior design, landscape, and product design, understood as one single conversation: that of the space we inhabit and the future we wish to build. See full biography.
Project by BAT
