Walls
90mm boards (R4.5, U0.02) face the solid timber outer walls, with all joints taped. In addition to keeping the structure dry, they also protect from rapid temperature fluctuations (no more ‘rifle-shot’ expansion sounds in summer).

Being inside the thermal envelope, the mass of the walls also help contribute to our thermal storage capacity.

Roof
The roof structure is limited – little space between the purlins was available for filling with insulation. Not wanting to disturb the ‘ceiling ribs’ internally, we opted for placing extra insulation externally. We settled for discontinuous 70mm boards between new purlins, not wanting to lift the roof sheets any higher.

Floor
Underfloor insulation was the most arduous part of the entire project; the sub-floor area enjoys clearances of between 200 and 400mm, so I resorted to polyester fibre and ‘snappable’ polystyrene panels.