Read of the Day: Great Designs in Wood (33) – Metamorphosis 1

Great Designs in Wood (33) – Metamorphosis 1

The nice thing about researching advances in wood utilization is that, contrary to what most people think, the world of wood use is ever-changing and advancing. We’ve talked a lot about that in the realm of bioenergy, but it’s just as true in the world of wood construction.

The Metamorphosis house of Tunquén,Casablanca, Chile is an example of how home owners and their architects are re-thinking how they use wood to relate to their environment.

This stunning project is a 2007 remodel of a home built in 1990.  It was pretty nice for that time, but looking dated. Architects José Ulloa Davet and Delphine Ding changed that by retrofitting the home with a new skin, a ventilated wooden facade. This was a new concept to me, and a little research on Wikipedia reveals that the general concept falls under a heading of rainscreen cladding, which is…

“…the attachment of an outer skin of rear-ventilated cladding to a new or existing building. The system is a form of double-wall construction that uses an outer layer to keep out the rain and an inner layer to provide thermal insulation, prevent excessive air leakage and carry wind loading. The outer layer breathes like a skin while the inner layer reduces energy losses. The structural frame of the building is kept absolutely dry, as water never reaches it or the thermal insulation. Evaporation and drainage in the cavity removes water that penetrates between panel joints. Water droplets are not driven through the panel joints or openings because the rainscreen principle means that wind pressure acting on the outer face of the panel is equalized in the cavity. Therefore, there is no significant pressure differential to drive the rain through joints. During extreme weather, a minimal amount of water may penetrate the outer cladding. This, however, will run as droplets down the back of the cladding sheets and be dissipated through evaporation and drainage.
By insulating the structural wall externally the following benefits are achieved:
  • Thermal bridging is somewhat reduced because there are no interruptions caused by floor slabs, however vast thermal bridging is more than likely introduced by means of continuous furring strips. Options do exist to help reduce the amount of thermal bridging introduced or even eliminate the thermal bridging altogether by truly insulating continually across ALL structural members with not breaks or bridges in the insulation except for the finite fasteners used to attach the cladding to the building (negligible by ASHRAE 90.1 standards since their thermal bridging effect is so slight)
  • Temperature fluctuations are minimized due the achievement of higher effective R-values (lower U-Values) therefore creating a much more efficient wall assembly and dramatically reducing the loads on HVAC systems.
  • Interstitial condensation is prevented as vapor pressure and wall temperature restricts condensation to the ventilated cavity.
  • Heat from the sun is dissipated so that the temperature is dispersed in the cavity and ventilated through openings.”


Before and after.

I was frustrated in my efforts to find out the species of wood used in either the external skin or in the beautiful internal remodel. If there are any readers out there who know, please share with us in a comment. What I do know is that the overall impact is one of total immersion in a wood environment, without being overwhelmed with the folksy feel wood sometimes conveys. This structure says ultramodern and wood at the same time.

Another great job of Going Wood. This is one structure I would pay to travel and see. And of course, sip a few margaritas while contemplating the essence of sea gull behavior.

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