Sustainable Residential Building

Today on our blog we will introduce a topic that is very much on the agenda, as it represents a commitment to the future for cities and urban centers.

Proposing an efficient residential building may seem unfeasible, but the truth is that it is something increasingly being pursued, and examples of this type of construction exist in cities around the world.

In this article we will focus on timber as an efficient construction system for achieving a sustainable residential building. We will explain how we can leverage its qualities and advantages to justify the commitment to this construction material, and we will conclude with a practical case currently under construction in Barcelona.

It is a sustainable residential building designed by a team of architects and a collective of residents through an interesting participatory model.

Let’s begin!

Timber as a Construction System for a Sustainable Residential Building

Although timber construction is not very common in Spain, efficient construction policies have recently favored the use of this material, as timber is one of the most sustainable construction materials available on the market, both for its properties and its capacity to be completely renewable.

While it is true that timber as a construction material is generally used more in single-family homes, there is currently an increase in its use in multi-family residential buildings.

We understand a sustainable timber residential building to be one whose structure and enclosures (walls and ceilings) are constructed entirely in timber and which also operates in an energy-efficient manner.

The versatility and flexibility that timber offers as a construction material allows us to adapt to different situations thanks to the wide variety of construction details that the material enables us to design.

To construct a sustainable residential building, we will opt for a structural system of timber columns and beams.

As reinforcement to this main structure, we can fill in with frames that serve simultaneously as substructure and support for the walls that will enclose and separate the dwellings or rooms.

These walls can be either prefabricated timber panels (the insulation is already included in the panel), or a framework can be generated on site that will be filled with natural fiber insulation or other insulation of natural origin and closed with timber planks or boards.

When working with a flexible material such as timber, we have a wide variety of construction systems, enclosures, and finishes with which to design.

However, at a thermal level, it is necessary to know how to counteract the low thermal inertia of the material to achieve a sustainable residential building that does not lose heat and consumes little energy.

For this, it is vital that the building is well insulated. If we ensure the airtightness and insulation of the building, we can guarantee an effective heating and cooling system throughout the year.

The La Borda Collective. Who Are They?

This is the case of La Borda, a collective formed by more than fifty residents of the La Bordeta neighborhood, in the Sants–Montjuïc district (Barcelona).

This collective was created in 2012 with the aim of constructing a residential building under a right-of-use model. That is, to build a building that would respond to “the need to access decent, social, affordable, and environmentally sustainable housing with the aim of promoting new forms of coexistence and generating community through interaction among residents.”

For the construction of the building, the La Borda collective also has the support and participation of other cooperatives that have helped them actively and democratically manage all phases of the business project. Among these, it is important to mention the LaCol collective, responsible for developing the architectural project for the dwellings.

What Do They Do?

The entire project revolves around an innovative right-of-use model, a system based on collective ownership where dwellings are neither purchased nor rented.

It is a model imported from countries such as Denmark (Andel model) and Uruguay (FUCVAM model) and provides for a double transfer: of land and of dwelling.

The right-of-use model allows for addressing potential speculation. It also represents a radical change to the traditional idea of housing, becoming a viable alternative in the field of public housing and a new form of access and management for people with low incomes.

How They Do It

In the case we are explaining today, La Borda, it is the Barcelona City Council that transfers public land to the cooperative, designated for the construction of Social Housing (VPO), with a surface right of 75 years, in exchange for payment of an annual price.

For their part, the member-residents must meet the VPO criteria and assume the cost of constructing the building or its rehabilitation through an initial contribution of €15,000 and a loan, which they will amortize by paying a monthly fee affordable to their means.

Members are free to leave the cooperative at any time, also recovering their initial investment.

The Result

At the architectural project level, the result of the entire process incorporates the proposals put forward by the residents regarding the building’s program, environmental strategies, dwelling typologies, and required service spaces. Finally, the executive project reflects the construction of a community formed by different and multiple family structures.

The building thus responds to three principles:

1. Redefining the Collective Housing Program

Regarding the program, this sustainable residential building includes 28 dwellings of different typologies and common spaces, which are organized around a central courtyard.

The common spaces on the ground floor are: a kitchen-dining room, a shared workspace, a laundry room, a multipurpose room, a guest space, a health and care room, and bicycle parking.

This layout recalls the organization of traditional Catalan farmhouses, where spaces for livestock, work areas, and the kitchen were located on the ground floors to take advantage of the heat produced to warm the rooms and bedrooms on the upper levels.

In addition, outdoor and semi-outdoor spaces for community use are proposed, such as the courtyard, the green roof terrace, a terrace with urban gardens, etc.

The design of the dwellings is based on a standard typology of 40 m², which can be expanded with one or two additional modules if a larger dwelling is needed.

To respond to this flexibility, the project opts for using timber as a construction element for both the structure and dividing elements (floors and walls). Timber is an ecological, versatile, and resistant material that offers the flexibility and strength necessary to construct a sustainable residential building.

2. Sustainability and Environmental Quality

Another of the main objectives of the La Borda project was to achieve the construction of a sustainable residential building, that is, with the lowest possible environmental impact, both during construction and throughout its useful life.

However, achieving this could not compromise the comfort of the building’s users; quite the contrary. The comfort of the building’s residents had to be guaranteed with minimum consumption, in order to reduce the overall costs of accessing housing.

The building’s approach is based on minimizing the initial energy demand of the building (electricity, water, materials, waste management, etc.) and prioritizing passive strategies or consumption of renewable energy, making maximum use of existing resources on site.

3. User Participation

During the design, construction, and use process of the La Borda building, the participation of its future users has been taken into account, as they represent the most determining variable of the project.

The connection and communication between the collective and the architectural team in charge of the project has been constant and vital to achieving a result tailored to all the residents of this example of a sustainable residential building in Barcelona.