Here are a few pics of the installation of the piping for the in-floor hydronic radiant heating system. The PEX tubing is clipped onto the cured and hardened polyurethane foam insulation.

All wiring and plumbing for the ground floor is now complete; even the in-wall toilet tanks have been installed. After having removed all materials from the ground floor and a thorough cleaning, we are ready for the next step: PU foam spraying. Traditionally, radiant heat in-floor installers use hard PU foam squares or sheets that interlock with each other. These sheets provide the insulation required between the concrete slab and the hydronic piping. The drawback with the hard PU foam sheets is that they need to lay on a flat surface and therefore in our case, we would have had to pour a sub-layer of concrete to embed all wires and pipes and level the surface to receive the hard PU foam squares. Unfortunately, the architect plans had not taken into account this extra layer of concrete.The option was to either lower the suggested height of the PU insulation or to look at other solutions such as the sprayed PU foam.

Before spraying the PU foam, the contractor had to protect all the walls, windows and ceilings as the foam particulate tend to fly all over the place and easily cling on to glass and wood. The foam was sprayed in several layers to give it time to expand and harden. The following day, the foam was sanded and levelled to a consistent 9cm thickness. The foam, once hard, can withstand a weight of 20 tons per square meter.

The inside walls on the ground floors are built using wood studs, Fermacell sheets and wood fibre panels. They are 20cm thick and the construction system used is to ensure maximum sound-proofing between rooms.

• The wood studs are placed so that each side of the wall has its own stud frame independent from the other.
• One layer of Fermacell sheets is placed on one side and two layers on the other.
• Wood fibre panels are placed in between the two wood stud frames to absorb sound.

The idea behind a proper sound-proofed wall is to create a system of sound-absorption-mass. Sound hits a hard surface and part of it bounces back. Some of it still goes through and gets absorbed by the sound-absorbing material. The remainder of the sound that manages to travel all the way through will bounce back on the hard surface on the other side of the wall. Other factors come into play such as the density of the hard surfaces, absorption factor of the sound-proofing material and the thickness of all these different layers. Based on the structure of our interior walls, we hope to achieve a rating of R’w = 55 db which corresponds to what is usually required of inside walls in hospitals.

Fermacell sheets are similar to the traditional drywall sheets with a few exceptions: they are made of a mix of natural gypsum (80{86faa949d09500cfb2fb8be01edc8582822a5980221f039bd4bbebd1d0646763}), cellulose fibre (20{86faa949d09500cfb2fb8be01edc8582822a5980221f039bd4bbebd1d0646763}) from recycled paper and water. There is no other bonding agent or glue. The result is a stronger, denser (heavier) and more eco-friendly material than drywall. Although its use is becoming more and more accepted and common in France, prices remain slightly more expensive than drywall.

The initial design of the house included a heat retaining wall. The purpose of this wall is similar to a Trombe wall which is to absorb solar energy coming through a window during the day and to radiate it back into the house at night. The wall separates the kitchen from the living room and faces the three big bay windows in the living room. The effectiveness of a Trombe wall or heat retaining wall relies on the material being dense and good at accumulating heat. Bricks, mortar made of soil and sand, and stones are all good examples of heat absorbing materials. We chose stones as we have plenty of them close to the construction site and thought it would be nice to have some visible stones inside the house.

As we built up the brick envelope around the window and door openings, we installed lintels above each opening. These will serve not only as trims or casing for the top part of each opening but also as a support on which the next row of bricks will rest. Using one solid piece of wood for this operation was not an option given the width and depth of the openings. We opted for building the lintels and casings out of an assembly of planks and small beams.

This might be considered as over-killed but we did not want to take any chance of having window casings damaged with water penetration. During hard and heavy rain falls, we noticed that there was some water penetration above the window and door openings at the junction between the stone wall and the concrete lintel. During heavy rain falls with wind, a few drops of water could be seen at the edge of lintels at a few openings inside the house. Although we have not seen any water since all the roof gutters have been put in place, we preferred to be safe and decided to install gutter pans under each lintel. These gutters are another one of those home-made inventions my father made and we are pleased with the results.