GRX Arquitectos interview by Intro Magazine

GRX Arquitectos kept a short interview by Tereza Svachova for Czech architecture magazine INTRO added to 14th publication dedicated to stone architecture.

Why did you decided to use local raw stone cladding? Why didn't the house simply remain in concrete.

Carlos Gor: A two-sided concrete needs different constructive sophistications that we knew it were a hassle for the local builders and we wanted only simples detail to execute. On the other hand, we didn´t want to generate a "strange object in the landscape" but an architecture that neighbors understood as logic for that place, that could serve as a model to sew the border of the town and that is why we looked for a stone that would be recognized as the old local constructions or the agricultural walls.

Álvaro Gor: The client also welcomed a difference between the "heavier" exterior and a "softer" interior.

What is the specific type of stone you used here?

Agustín Gor:We had the idea of using the stone from the same land as the house, since it is very common for there to be a large amount of stone on the ground and thus transform the land into architecture, but it turned out the land was better than we expected and not had stones. We went to a local quarry and saw that they accumulated a type of white stone that we liked very much: large size but manipulable by one person.

Álvaro Gor: It turned out that this stone was the leftover from generating large stone slabs and it was sold to make gravel, so it was extraordinarily cheap. It is a very common sandstone in the area, very easy to work with and quite light, which allowed workers to handle it despite its large size.

What is the tradition of using stone in architecture in this area?

Carlos Gor: Before the arrival of standardized materials to rural places in Spain in the 60s and 70s, all local construction was done with a mixture of mud and stone, basically transforming the territory into architecture. In the same way, the agricultural retaining walls are made of stone. So if you walk around the environment, any agricultural construction, or any traditional building witch has lost its coating reveals the masonry.

How is the stone cladding technically anchored to the load-bearing structure? In detail, it seems that, for example, only some stones are firmly anchored to the roof structure.

Álvaro Gor: We planned to use a patented system to anchor the stones to the concrete wall because we had planned a smaller stone size and it was necessary to avoid detachment. But during construction we discovered that it was unnecessary, the size of the stone was larger than expected and we liked that because of its brutal appearance and because it stood on its own without problem.

Agustín Gor: On the roof we were also surprised because the stones were perfectly held by friction and weight, no type of anchoring was necessary. Even so, we fixed some of them, but we were very clear in indicating to the workers that the stone should only rest dry because it was essential that the water ran under the stones and there should not be elements that impeded this circulation. Our intention is that, with time, sand will be acumulated in the roof and walls and the house could be covered by vegetation.

How complicated it was to put the different shapes of the individual stones together? Did you have to choose individual pieces for a long lime, or were you lucky and they all fell more or less together?

Álvaro Gor: This question was key in the final appearance of the house. There was quite a variety of sizes and shapes of stones, and the worker in charge began to assemble them "too well", almost like a perfect puzzle placing the flat faces outwards. It was a problem to make him understand that the placement had to be more random, avoiding that flat faces cut by the machine could be seen, with a natural appearance.

Carlos Gor: This was not only for appearance, on the roof the stone density should not be very high cause the weight and for the water to pass well between the stones, which favored that the flat faces served to support the stone. We had to place some stones "wrong" ourselves during some days so that the worker understood it well.

At the photos, the house is captured under a sprinkling of snow. How often does it snow in this area?

Carlos Gor: Although the house is in Andalusia, Puebla de Don Fadrique is a village that is located at a high altitude and next to mountains, so snow is quite common. We always stop by the house to see how different phenomena (a lot of rain or snow) affect the house because of the unusual nature of the technique and we are surprised by how well it works. Coincidentally this year the storm "Filomena" has left up to a meter of snow in the area that can endure for months because it is a cold place in winter. We were amazed at how quickly the snow cleared, faster than on conventional sloped roofs. The gaps between the stones made it easier for the snow to fall apart and prevent it from falling off the eaves, which has been a safety problem in the town.

Agustín Gor: Despite having some experiment in the details of the house, all of them have been done with enough care to make sure that they were not an inconvenience but that they solved problems that the conventional architectures of the area suffer.