The five earth sheltered houses. Image by WindandSun who provided the PV installation
The Hockerton Housing Project is the UK's first (and almost only) earth sheltered housing development. It is a remarkable place, not only because of the five houses which are built into the side of a hill and are almost zero energy but also because of the water collection off the land behind the houses, the treatment of sewage through a wetlands system, the wind generators, and their local transport systems. They do excellent tours around the place and are extending their skills into a wider community.
There are two possible criticisms of this kind of earth sheltered housing:
- the large amount of concrete needed to form the main underground structure
- the limited amount of natural daylight available on the side of the building covered by earth
Countering the argument about the embodied energy of the concrete is the fact that the earth roofs and walls themselves do not have any further significant energy input such as you get with bricks, blocks, cladding, tiles etc. Along with that comes extremely good air tightness on the earth sheltered side of the building
Undertaking this type of construction demands considerable understanding of concreting. The concrete must be absolutely waterproof so that underground water cannot find its way into the building. This also involves correct design of the structure, especially the steel reinforcing and expansion joints.