The project is born from the need to move the office to a bigger place. An opportunity is found in Blonay (Switzerland) with a piece of land on which foundations have already been poured for a duplex.

The goal is to build 3 modules (1 office and 2 apartments) on existing foundations. The task is difficult since several parameters have to be taken into account:

• Noisy highways in the vicinity (one hundred meters below).
• Existent fondations.
• Green construction.
• Wood as the main building material

The architect, Dominique Molard, combines technique and creativity. He uses the offices west wall as a noise barrier for the 2 apartments. The work begins by pouring the slab.

From now on, wood is the main actor, not only with the roof structure but also for walls, floor, and interior partitions. From April to June, the team works in a shop to assemble individual construction elements. In July, the erection starts and it takes 6 days to assemble all. Then other trades follow and early November the place is ready to move in.

The environment : the priority

Material available onsite are used as much as possible:

• Excavated stones are being used as terrain walls and for pavements.
• Poplars that have been fallen have been recycled for inside trim.
• Rain water is stored in 13 200 liters tank, in order to cover the use of water for toilets and the garden. The excess is redirected to a pond.

The whole construction treats rain water carefully since the roof collects water in a tank and the parking spaces are designed with permeable materials. Currently, gas provides the energy needed for heating. Subsequently, solar panels will be installed for this purpose. As for the vegetation, plants and trees are native. Green roofs increase the green surface and provide employees as well as neighbors with a pleasant setting. The natural amenities have been certified by the Nature and Economy Foundation, which awards a label "Natural Parks" to private companies that promote the environment in their development.

Construction system The whole construction was panelized and used innovative methods. The latest developments in adhesives has been used for wall siding as well as for floor panels. Insulation consists of cellulose coming mainly from old paper blown up in cavities within wall and roof panelscadwork has been used to plan the whole construction with the tinniest details. It enabled all the parts to be machine cut using the latest CNC available on the market. A 5 axis machine was used to precut the trusses that give the construction a unique character.

Panelized system To assure a good dimensional stability, all lumbers have been sawn in two along the length, dried, glued back together and then planned to the finished dimension. The bracing is done by 12mm OSB placed on the inside. The wind barrier is constituted by wood fiber panels which at the same time improves the R value of the walls. On the inside, plaster board reinforced with wood fibers are fasten to a 40mm furring which leave enough space to run the electrical system.

Oversized roof overhangs protect the walls sidings. However, 20mm rough sawn larch siding protects the panels from rain and UV. The siding was connected to the panels using a flexible adhesive enabling them to vary in dimensions during the seasonal climate variations. An invisible connection also assures a long life span because the siding surface is not altered.

The aesthetical aspect is also improved since the usual fixation leave marks on the siding. Once all panels are prefabricated, the assembling can take place. Once all panels are assembled, the cellulose can be blown in. This type of insulation makes the whole construction tight since it fills the smallest gap. It also prevents drafts and condensation.

This type of insulation can absorb moisture in form of vapor and thanks to that ability, regulates the moisture content in the wall without stopping it. This characteristic has another advantage, there is no need for a vapor barrier as long as the material on the outside can diffuse enough vapor. In our case, the soft wood fiber panels guaranties an optimal diffusion like Gore-Tex fabrics.

Floor system

Floor panels have also been prefabricated and the aesthetic was not left behind. In order to reduce the panel depth, all panels have a width of 2150mm that were assembled with timber joists and 3 layers laminated timber panels. The connection between the joists and the panels is done using glue that only requires low pressure.

This type of glue was used because other fasteners like screws or nails would have taken more manufacturing time and would have also reduced the aesthetic. Therefore, the cross-laminated timber panel makes a nice ceiling. In order to reduce acoustic problems and vibrations, it was insulated and loaded with concrete.

Timber/glulam

• Spruce glulam 5.6 m3
• Larch glulam 15.2 m3
• Circular larch glulam 3.8 m3
• Glued timber (2 laminates) 52.3 m3
• Timber 10.0 m3
• Total 87.0 m3

Engineered wood products

• 3 layers laminated timber panel - spruce 27-30mm 800 m2
• Larch panels 110 m2
• OSB panels 12mm 900 m2
• Wood fiber panels 22mm 900 m2
• Wood fiber reinforced plaster boards 900 m2
• Total 3600 m2