Now that we are watertight, the insulation was next on the schedule. The Diamond Bead vans arrived carrying our little silver polystyrene balls. This is what is going to keep us perfectly insulated, warm in the winter and cool in the summer!
Holes were drilled and in they were pumped. They are pumped under pressure so that the beads fill every cavity. As they are pumped in they are covered in an adhesive so that they will form a solid block, they aim to get about 12kg/m3. This means, in the future, alterations can be easily made as there will be solid blocks of insulation rather than millions of little beads. No fire risk as there is not enough air to support combustion, and these little guys are so stable they will definitely be around for the life of the building.
This may not be the most sustainable material we have used, polystyrene balls...but in this application we are all happy that it's the right choice. They have a fantastic insulation value of 0.031. Our walls cavities are already 370mm (developers normally have 100mm), had we chosen anything else we would have had to make our walls even thicker to achieve the same insulating value. It would have been lovely to use sheeps wool or recycled newspaper, but the looking at things in the round this was our best option.
The Diamond Bead guys were fantastic - able to come on short notice all the way from Devon and dealt fantastically with us concerning the additional extra volume we required. The holes were all taped over and job done. Snug as a bug in a rug.