A Modular Project Like an Assembly Game: Mass Timber Prefabricated Houses
Jun 07, 2023
Prefabricated wooden houses date back to the 19th century, when so-called "kit houses" became popular in North America. Sold by companies like Sears, they offered affordable and convenient housing options, especially for people living in rural areas where labor was scarce and expensive. Customers could choose from a few designs and dimensions, and the kits usually included all the materials needed to build the house, including numbered and precut lumber, nails, shingles, and other necessary components. For some time, however, prefabricated houses were seen as constructions of lesser quality and prestige, and coupled with the lack of flexibility of these solutions, they went into decline.
Nowadays, thanks to the technologies available in the market, modular and prefabricated constructions have emerged as clean, sustainable, and energy-efficient construction solutions. In addition, innovations in engineered wood have emphasized its many uses, with the added benefit of aesthetic and structural possibilities. It was in this context that the office UNA BV developed the Modular 5.5 project, whose goal was to create flexible modular constructions that could be assembled in different arrangements, allowing the construction of houses with a variety of dimensions and needs in different terrains. We spoke with Fernanda Barbara and Fábio Valentim about this project:
Eduardo Souza (ArchDaily): How did you come up with the idea of developing Modular 5.5?
Fernanda Barbara and Fábio Valentim (UNA BV): The idea came up within our office; not as an external demand from clients or partners. The project was built over a few years, arising from a number of issues that have been important to us for a long time, especially in relation to ways of building and who we can serve with these projects. Modular 5.5 stems from the study of sustainable materials, using reforested wood structures and closings. It is also an exercise in building based on the largest possible number of components that arrive on site ready to be assembled, resulting in a fast construction with little waste and low impact on the site. Small and medium-sized constructions (such as houses) make for particularly good experiments.
With these premises we developed a modular project that works like an assembly game, with diverse compositions.
As there are still only a few companies that make this kind of wood structure (industrialized from reforested wood) in Brazil, we understood that this modular project can serve a much larger number of people than a conventional one. It is important to emphasize that Modular doesn't have information about the times and costs of a project (only of implementation and adaptation to contingencies), and the construction is also very fast, generating a significant economy in terms of time and in the process as a whole.
ES: What solutions were used in this project?
FB/FV: We chose to structure the system with industrialized reforestation wood. As we said, it is a product of low environmental impact based on wood of certified origin, that is, a renewable resource.
The system consists of Glued-laminated timber pillars and beams and Cross Laminated Timber (CLT) panels. These panels are used as the perimeter enclosure of the construction and support of the roof, which creates an interior environment where wood predominates. That is, the system already has its own finishing pattern that creates its own very distinct interiors.
Another concern was the design of a generous roof, with wide eaves that protect the rooms from excessive sunlight and rain. The window frames were designed in two levels, which allows the most efficient use of cross ventilation as a natural resource for temperature control.
Modular can accommodate various topographies, dimensions and terrain geometries. A standard 'radier foundation' solution was developed under the entire area of the house, from which the wooden structure is fixed, but other types of foundations may be required.
In other words, this mounting system adapts to the terrain, and it is the specific conditions of each place that determine the best solution for the installation and foundation. The project is designed to include solar panels and photovoltaic plates, in addition to, eventually, a biodigester and a water reuse system.
The idea was to create a system, not a closed project. We designed modules with basic functions, such as living room, bedroom, veranda, office and garage, that can be assembled in infinite ways, composing houses of various dimensions and needs for any kind of terrain. It is also interesting that we arrived at a type of module that is suitable for several uses other than residential. We are already doing some implementations of Modular 5.5 for other programs, which has been very interesting.
ES: How was the decision made to use Mass timber in this project? How did this decision impact the project? What were its limitations?
FB/FV: The option for Glued-laminated timber reflects the desire to work with an industrial system based on a product with a low environmental impact, which is the case of reforested wood (eucalyptus, predominantly). In addition, the wood solves not only technical issues but also finishing issues. In the development of the project, we counted with the assistance of Crosslam, which became a partner company of the project. Besides them, we also established a partnership with a construction company with whom we already had a lot of work in common, Taguá Engenharia.
ES: How could this solution be adapted to more than one climate? Are there any plans to build a physical prototype?
FB/FV: We have carried out studies to implement the system in very different conditions; by the sea, in the mountains, in states north and south of São Paulo. The system already foresees these adaptations, showing great versatility. We are already working on some Modular implementations and soon we will have built houses.
ES: How do you imagine the future of this project?
FB/FV: When the first units are built, we will have some real feedback from the conditions in different situations. The system can always be improved, and the range of variable components can grow, supported by demand.
We already have plans to develop other types of modules that can address some specific situations not yet addressed by Modular 5.5 (such as a module system that can have more than one floor).
ES: In your opinion, what are the possible contributions of architects to a future with more environmentally friendly, comfortable and affordable housing?
FB/FV: The issues related to construction, environmental impact and also to the construction of the landscape itself will be increasingly important. This is a worldwide problem, but we need to call attention to the urgency of this agenda in our countries. Naturally, architects are professionals able to synthesize diverse knowledge in the form of new construction modalities. We have this commitment.Eduardo Souza Eduardo Souza (ArchDaily): How did you come up with the idea of developing Modular 5.5? Fernanda Barbara and Fábio Valentim (UNA BV): ES: What solutions were used in this project? FB/FV: ES: How was the decision made to use Mass timber in this project? How did this decision impact the project? What were its limitations? FB/FV: ES: How could this solution be adapted to more than one climate? Are there any plans to build a physical prototype? FB/FV: ES: How do you imagine the future of this project? FB/FV: ES: In your opinion, what are the possible contributions of architects to a future with more environmentally friendly, comfortable and affordable housing? FB/FV: