Frost trunk

The frost road used in house construction to water under the foundation to direct downwards so that the bottom plate is not lifted from any water present in frost.

Before the floor slab or the strip foundation is concreted, a frost case between 25 and 70 cm deep must be provided, depending on the nature of the soil and the depth of the frost. It consists of angular material with fine particles, also called wall gravel. This is applied in layers and compacted vigorously.

In extreme cases, if too much water comes under the strip foundation or the floor slab after heavy rain, the house could “float” and the foundation could subsequently sink. If the subsoil is made of gravel , the floor slab can be built on it, otherwise a drainage system must be provided.