Demountable timber housing for 370 refugees – using no concrete at all

Demountable timber housing

A building that had to be erected quickly and which could also be taken down within ten years: these were the criteria for the Rigot Collective Dwelling Centre, a two-building complex providing housing for 370 refugees in Rigot Park in Geneva, Switzerland.

The client was Hospice Général – the main public welfare office of the Republic and Canton of Geneva – who provide assistance to asylum seekers, among their many other functions.

One of the Rigot Centre’s timber modules, being prefabricated offsite.

The solution, designed by Acau Architects, was two symmetrical five-storey buildings made from 230 prefabricated timber modules.

A stacked-up sanctuary of timber modules

Each module’s structure has a CLT floor with walls and ceilings made of glulam panels. There are two different types of module, with different functions. One comprises an access balcony and an entrance with a seating area and a free-standing kitchen module inside. The other has a sleeping area and WC.

The modules are arranged directly on top of each other, with the walls taking up the vertical loads, while the horizontal loads are channeled into the larch frame.

Side by side, the two symmetrical buildings sit in Rigot Park, Geneva.

The façades are clad in Swiss oak and the building’s entire design aesthetic seeks to express its wooden structure as honestly as possible.

Programme benefits of prefab

There was an urgent need for the building to be completed quickly. So the prefabricated nature of the modules played a decisive role.

Two different works could be conducted in parallel – the modules and the foundations being built simultaneously – with assembly and finishing following swiftly afterwards.

The floor slabs are CLT, while the walls and beams are glulam: all the wood is locally sourced

Flexible spaces for a variety of tenants

The modules allow the allocation of space to be varied in each apartment – from two to eight rooms – allowing for a variety of different tenants. Given the temporary nature of the project, this flexibility leaves open the option of later accommodating students, for example, or using the buildings as a hotel.

In addition, it is easy to reconfigure the buildings: they can be stacked in different formations to create two taller buildings or several smaller ones.

The dwellings are accessed by an external gallery open to a public courtyard, which connects both to the park and to a local public transport stop.

The modules can be customised to allow for differing numbers of residents per unit – and for new usages in future at a different location.

A building with clean feet

The foundations are a network of wooden footings and pilings made from durable larch, and they can be reused at a future new location after the two buildings’ deconstruction at the end of its 10-year tenure. This totally ‘dry’ construction – avoiding concrete – means no contamination of the surface water network during construction. The land can be fully reinstated once the buildings have been taken down.

Local Swiss timber

The use of local wood from Geneva’s forests for the foundations and the building envelope was part of the project’s brief from the very start, inviting tenders from local timber manufacturers. An estimated 3200 m³ of certified “Label Bois Suisse” wood (formerly COBS) was used for the buildings’ 1,848 m2 area, with the exception of the larch window frames on the façade.

Quality timber housing

The buildings, completed in 2019, have provided a striking addition to the area. Hospice Général wanted to commission buildings that further its creed that quality housing facilitates social integration, and Acau Architecture appear to have exceeded all their expectations.