We have been building some extra shuttering down the sides of the tunnel to form an extra thick footing to support the main house foundation as it goes over the tunnel.
Earth-tube-tunnel-finished
We have also built shuttering to form a ‘chimney’ to take the air from the tunnel up through the foundation and floor slab. This has been topped with a temporary air filter to allow fresh air into the earth tubes as we use this for fresh air in our living quarters.
Earth-tube-chimney
Also, while the shuttering was being constructed, old rubble and soil was loaded around the the Air Mixing Chamber and the Tunnel, compacted down and built up to somewhere the right level for the floor slab.
Ground-filled-around-tunnel
We will fill in with more sandy soil and adjust with more accuracy when the foundation strip is poured and set, we would have a marker to line up to then.