The selection of material for a certain project is influenced by many aspects; aesthetics, technical performance, familiarity with a material, costs and so on. When planning a new building as an architect, durability and sustainability are important factors, maybe more than ever. Natural stone is a good choice for Mother Nature.
The most common materials are glass, painted metal sheets, concrete products and natural stone. All of these alternatives should be evaluated based upon some key criteria’s for choosing a building material. In this case we will look into different concerns some architects have when considering natural stone for their projects.
Environmentally concerns about natural stone
Natural stone is long lasting and almost maintenance free. The material is natural and has no added chemicals. Granite is virtually immune to the ravages of Mother Nature.
On the pricier side of using natural stone, the production and extraction process can be quit energy intensive. The transportation of the material can also be a challenge when the quarry is far away from a harbor. But if natural stone is quarried in a modern way, mainly by wire sawing, and if the quarry is located close to a seaport, it will both favor natural stone compared to other alternatives, like glass, concrete products and metal panels when it comes to Co2 emissions. Fans of natural stone also often say that the longevity of the material makes up for the negative aspects.
The maintenance of the building, and requirements of heating or cooling, are also key issues depending on the material selected and its parameters.
A good example is the Frankfurt Opera Tower (The Opernturm) done by Mäckler Architects and the construction company Tishman Speyer. They considered the energy requirements of constructing and maintaining a glass façade and decided to compare it with natural stone from a life cycle assessment view. They ended up with a natural stone façade. The building was designed to consume 23 percent less energy than stipulated by Germany’s 2007 EnEV Energy Regulation. The Opernturm was one of the first office buildings in Europe to be certified to the Leadership in Energy and Environmental Design (LEED) Gold standard (source: Wikipedia).
Reuse of quarries
A stone quarry is normally not a pretty sight in the natural surroundings. Initially you can think that natural stone should be ruled out as a construction material based upon this argument.
Though, a lot of quarrying companies have regulations in the quarry license, saying that the quarry should be returned to a certain condition when the quarrying is ended. This could be a refill of the quarry pit, re-use for a residential purpose or other uses.
Probably the most known example of re-use of a quarry, is the football stadium Estádio Municipal de Braga (Portugal), the home for local club and UEFA Champions League 2013 contestant FC Braga. The stadium is also known as A Pedreira (The Quarry), as it is carved into the face of the adjacent Monte Castro quarry.
Heavy installations have safe solutions
Some architects are skeptical to the installation process of stone panels itself. The panels are heavy and the concerns are that they will break and fall down. The most common installation techniques currently used for natural stone curtain walls, are pre-constructed larger panel sections. When using this technique, the stone is anchored both in a chemical and a mechanical way. This type of installation will cancel the risk of broken pieces to fall down.
Will the color and gloss last?
When using natural stone, durability is for some architects a concern. Some other materials, as for example coated metal panels, come with a guarantee of 25 years. For granite there is normally no guarantees. But a natural granite stone façade should have almost no degradation of gloss or color if the right stone is selected. The best thing to do is looking for a reference project with a long history, as a proof of the stones durability when it comes to color and gloss.
Challenge the quarry company
Don’t be afraid to consider natural stone for your next project, but challenge the quarry company to support you during the decision process. They should be able to help you regarding location of quarries, technical data, reference projects and samples. The natural stone industry is not dominated by large multinational companies, but rather by small to medium sized family owned companies that takes pride in their natural stone and are more than happy to support designers interested in their material.