Questions re. Straw Insulation

The stone walls are almost finished and the roof wooden structure ready to be installed. Yet, we have not finalized the installation details of the 25 centimetres of straw insulation.

It is rather frustrating to get that far into the construction and realize that neither the architect nor the thermal engineer have thought through the installation details of the insulation system they recommended.

  • What are the details and specifications of the wood framing we need to hold the 25cm of straw in place?
  • Can we place the straw right against the stone wall?
  • If this is not recommended, do we have to leave an air space or install a vapour barrier?
  • How is the 4cm-thick soil-based plaster supposed to hold onto the straw insulation?
  • Do we need to plan for an air space or vapour barrier between the insulation and the final soil-based plaster?
  • How to ensure the walls+insulation+plaster will breathe properly and we will not have condensation issues?

These are all questions whose answers we are still looking for.

If you know of anyone (professionals or individual home-owners) who have experience and history about stone walls and straw insulation, please let us know; we would like to hear from them.

It would be sad to have to change to a different insulation system after putting so much work into harvesting and storing the straw required to insulate the house.

Back in France

I arrived in Bigorre yesterday morning. We spent the day picking up the straw bales as the weather forecast had announced rain in the evening. It was pretty accurate and as soon as we were done covering the trailers full of bales, the wind started to pick up and the first rain drops started to fall down.

We harvested 2 full trailers of rye straw bales which is about 450 bales. We hope that there will be enough to do the whole insulation on the house. It was a good workout because you have to use a fork, lift the bale above your head and carry it to the trailer. As the trailer gets packed higher and higher, it gets harder to throw the bales to the top.

While we were taking care of the bales, the masons poured the long reinforced concrete beam that goes from the water cistern to the front of the first cellar. Today, they covered the whole cellar and the rainwater cistern with planks and steel sheets to prepare for the reinforced slab. While they were doing this, Ismael and I cleaned the side of the road and took some soil away so that they will be able to extend the slab closer to the road and rest on top of the old house’s wall.

The slab should be pourred and finished by end of next week.

Tomorrow, the carpenter is coming and will start his work on the beams for the first floor. Everything is moving along and it’s nice to see. There is still tons of work to be done but it’s already starting to look nice.