We started to think about wood as a construction material some years ago. First, we were caught by the aesthetic appeal and the warmth of contemporary and traditional solutions all over the world, from Norway to Japan. We always questioned why couldn't we build with wood in Portugal. Then, when we started to think seriously about it, we acknowledged the importance of its environmental friendliness. Recently we concluded a research where we proposed an architectural design method to be used in Portugal.
The proposed method was developed to support the design of wood houses in Portugal. During almost five years I developed this study in IST (Instituto Superior Tecnico) with the support of LNEC (National Laboratory of Civil Engineering). Part of the work was done while working in Canada, where I could observe a context where wood construction is a very common process. First I didn’t understand why in Portugal, a country with such an important forest didn’t have a strong wood building culture. Then I verified that there were important reasons in the past that justify this situation, but I also concluded that the new solutions and contemporary advances in wood research allow us to overcome that problems.
The study of the wood houses market and the surveys I did gave me the conviction that it is very difficult for a client to understand all the diversity of the wood construction universe and its different products and potential. So, I understood that the old concept of typology should be fundamental to the client’s choice process. If we want to make a good choice, we must understand the relation between the formal systems of architecture and the wooden structural systems. The spatial, functional and symbolic concepts we have about a house must combine with the structural types we are going to choose. The first part of the method consists in a careful process of understanding the client’s goals and on the selection of the best typological solutions.
A schematic design definition for a wood house will follow the typological definitions set in the previous phases. The design of a solution must follow a specific order where the integration of the formal and technical factors is fundamental. For instance, it is important that the structural grid that we define will fit well in the spatial solution, especially when we deal with linear components. The definition of the building envelope will have to be thought in harmony with the defined structure. All this and other important design tasks will be optimized by the use of BIM software. We use ArchiCAD as a design tool, allowing us to check the above-mentioned relations.
The success of design processes relies in great part on the choice process. Designing implies the definition of alternatives and the choice of the best to conform to the defined scope. This is also the quest to find the solution who best fits the client. So we proposed the use of a multicriteria assessment method where we use different weighted criteria (for instance price, durability, architecture, and environment), in connection with levels of performance, allowing us to make the best choice. To be effective, the method prescribes a singular, thus always different, definition of criteria and weights to the specific client and context we are dealing with.
Although every wood construction system has its own technical potential and limitations, we defined a general framework that will support the design in a way where the final quality is guaranteed. Besides the use of specific procedures, there are general design strategies that will guide the process as in a system of design checks. So, three strategies were considered as the most important for wood design projects: Durability, construction integrity, and economy. Durability is one of the most important issues when we think about wood. Construction integrity is another fundamental theme especially when we join different components in a single work. Finally, when defining the wood materials and components, some economies can be reached if we know the technical logics of wood construction.
Our method was based on the observation of the different possibilities the clients of wood houses have in our market. We know the advantages and limitations of going directly to a wood houses company or to contract a ``star-architect`` or an architect that doesn't have the expertise to design with wood. There are very good house companies and if you want a standard and secure product that's fine. Portugal is also known for having some very good ``star-architects`` that have their own ``brand``. If you have not your own vision and if your budget is not limited, that's a good choice as well. Hiring an architect that doesn't have the right knowledge about the main issues of wood construction, just to save money, might be an error. We would like you to trust us. The advantages we think we can offer you are as follow:
One of the misconceptions about wood construction is that it is just a single system with its own rules, but that's not true. Different wood systems have different logics and specific conditions. Some people think about wood because they feel the appeal of the natural materials and traditional methods. Others believe in how great is to express the contemporary values of life with simple spaces and clean wooden structures. Some could value the economies they will get from wood systems or praise the technical advantages of its lightness. Yet, in some cases, wood will be the most expensive solution, only available to those lucky enough to have a very flexible budget. Wood can fulfill all these demands. So, the first important thing to understand is that wood is apparently a simple material but it can not be simplified.
Just as a reference, these are the four main construction systems in wood we will deal with in Portugal: