Methods of construction

All of the different earth construction techniques demand protection from strong sunshine and from heavy rain. It is also advantageous to build during early summer so that walls are dry enough to be rendered during the autumn.

Foundation materials for earth buildings are stone, earth mixed with Portland cement, lightweight expanded clay blocks or normal concrete. Foundations should be built to at least 40 cm above ground level, so as not to be splashed by rain, and must be at least as wide as the earth wall itself, usually about 40 cm. In concrete foundations the bulk can easily be increased by adding up to 25% of rubble, e.g. fieldstone.

If unprotected, stone and concrete walls can absorb a great deal of moisture from the ground through capillary action - rising damp. In earth buildings this must at all costs be avoided since earth structures are even more sensitive to moisture than timber construction. A damp-proof course must be laid at the base of the wall. This is often done with asphalt, or can be a small layer of strong concrete that also serves as a strengthening ring beam. Slates can also be used.

Pisé (earth ramming technique)

Earth suitable for ramming contains primarily sand, fine gravel and a certain amount of clay which acts as a binder. Ramming consolidates and binds the components. As with all masonry-type materials, walls should be kept humid and should not dry out too quickly. After the

13.19

Swedish model for shuttering. Source: Lindberg et al., 1950.

13.19

Swedish model for shuttering. Source: Lindberg et al., 1950.

building process the wall will be cured by substances in the air and can eventually become almost as hard as chalk or sandstone. Shuttering and further equipment is required for ramming.

Shuttering and ramming equipment. Shuttering must be easy to handle and solid. There are many patents.

0 0

Post a comment