Construction Systems
Building a Wooden House in Catalonia
This week we visited the town of Rialp, located just over two hours from Barcelona, in the Lleida Pyrenees.
The purpose was to visit the company Fustes Sebastia, the first wooden house construction company in Catalonia and, as of this week, a construction company associated with Slow Studio.
Fustes Sebastia is a family business that began as a timber sawmill over 50 years ago and has specialized since 2009 in the construction of wooden houses in Catalonia using pine and fir timber from local forests.
After more than three hours of meetings and a visit to the sawmill, construction workshop, and offices, we left convinced that they should be our number one builder for Slow homes in the timber version.
Specifically, Sebastia works with timber from Pyrenean forests, sourced from forestry operations that municipalities put out to public tender for forest maintenance and conservation purposes. In upcoming articles, we will discuss forestry in greater detail—an essential activity in our forests to preserve biodiversity and promote sustainable economic activity while helping to prevent forest fires.
Since the forests of Catalonia—or southern France—are not comparable to Nordic or Central European forests, where timber grows straight and easily exceeds 10 meters in height thanks to proper forest management, in Catalonia the forests consist of small and irregular trees, meaning the extracted timber allows us to construct wooden houses with smaller columns and beams.
To compensate for this limitation, Fustes Sebastia imports some timber from Germany or Austria, especially for houses requiring large-scale structures.
Thus, when building a wooden house in Catalonia, we distinguish between two construction systems based on the origin and structural type of the timber:
– Light timber frame house
– Cross-laminated timber wall house
Of course, the wooden house can also be the result of a combination of both systems.
The difference between the above systems is not solely the origin, since in fact, at Sebastia they told us they are already preparing the workshop to offer the cross-laminated timber wall system with local timber from Catalonia, but the difference also lies in prefabrication and consequently in construction time.
Let us examine each system in detail to better understand the concept:
building a wooden house using light timber frame
A light timber frame house, as its name suggests, is built using lightweight timber elements. This type of wooden house has been and continues to be the most popular worldwide, because it does not require large forests. In the United States, in fact, it remains one of the most common construction systems for wooden houses.
This system is based on constructing “boxes” formed by timber columns up to 9 meters in height, placed approximately every 1–1.5 meters and enclosed with timber or fiber panels. Inside each “box,” insulation is incorporated in the workshop—in this case we will opt for natural, ecological, and breathable insulation such as wood fiber—as well as the installation runs, which are completed in the workshop.
The fact that the installations are completed in the workshop saves considerable time on site, where any change is expensive and slow.
While each wall is assembled and finished in the workshop, the foundations of the house are being prepared on site—normally in concrete—so that when the foundations are ready, the semi-prefabricated wooden house can be transported to the site, reducing the total construction time to less than six months.
A House Manufactured in the Workshop
Another advantage that has popularized this system is that it can be completely prefabricated in the workshop, with the insulation and installations of the wooden house walls prepared and then transported from the workshop to the site, considerably reducing construction times.
building a wooden house using cross-laminated timber wall
A cross-laminated timber wall consists of a panel of boards between 2 and 4 centimeters thick and between 20 and 25 centimeters wide. Each panel is glued and pressure-bonded with two panels arranged in a horizontal-vertical-horizontal grain orientation.
The timber composing each panel can vary, allowing combinations of pine, fir, or larch, among others.
If greater strength is required, instead of three layers, we can compose a panel of five or even seven layers, in which case it is also possible to include a channel for installation runs in one of the layers.
The result is a structural wall that can be installed on site without the need to add any additional structure, other than insulation—always on the exterior façade zone—and finishes. Depending on the design of the house, if we correctly distribute the installation runs, it is possible to achieve vertical timber walls with a finish of pine or fir boards.
The Combination of Both
Finally, a third construction option would be the combination of both construction systems, constructing the walls with light timber frame, which allows us to prefabricate all installations in the workshop, and the floors and ceilings using cross-laminated timber structure, which allows us to achieve larger spaces.
building a wooden house in catalonia that functions without heating
Although on this occasion we have focused on explaining the construction system for building a wooden house in Catalonia, it is important not to forget that today the primary objective of building a wooden house in Catalonia or any other location is energy efficiency and the sustainability of the entire process.
At Slow Studio, we are so committed to energy efficiency being paramount that we sometimes take it for granted, but it is important to remember that these homes are of course highly efficient and can function perfectly without the need for heating, maintaining a stable temperature throughout the year between 19 and 22 degrees.