Shallow-Depth Foundation

Construction of a Shallow-Depth Foundation

The base of this foundation type is a sand cushion placed in a previously prepared trench 0.5–0.7 m deep. Typically, coarse-grained sand is used, which is laid in a 0.3–0.5 m layer on the trench bottom, depending on the future building’s weight and soil type. After completing all preparatory work—including applying a waterproofing film to trench side walls, installing ventilation pipes, and connecting utility conduits—the reinforced concrete footing is poured.

The sand cushion partially replaces frost-susceptible soil with non-frost-susceptible soil, protecting the entire structure from destructive effects of low temperatures and groundwater. Coarse-grained, water-permeable sand helps prevent foundation damage even without a drainage system, as it allows water to distribute evenly along the entire perimeter of the concrete footing.

Construction Requirements for Shallow-Depth Foundations

To ensure structural stability and reliability, several key recommendations must be followed during foundation construction.

• Do not begin foundation construction on frozen ground. Wait until the ground has fully thawed and groundwater has receded.
• It is not recommended to leave a shallow-depth foundation unburdened during winter. If the building cannot be completed before winter, install a temporary insulating layer around the unfinished structure to protect it from freezing. Materials such as straw, sawdust, expanded clay, slag, and others can be used.
• When installing the sand cushion, carefully assess the soil. If the soil is permeable to water, lay coarse-grained sand in thin layers, each of which should be watered and compacted.
• Pay special attention to the waterproofing layer. It must be installed carefully, ensuring no gaps or poor contact. When using liquid waterproofing, apply two layers.

Main Advantages of a Shallow-Depth Foundation

This type of load-bearing structure offers numerous benefits, which explain its popularity in rural construction. A shallow-depth foundation is installed at a minimal depth, significantly reducing both construction time and material costs. For example, deep foundation construction typically accounts for up to 1/3 of total home construction costs, while shallow foundation costs rarely exceed 1/7 of total expenses.

A shallow-depth foundation greatly reduces the risk of base erosion by groundwater. This structural solution simplifies construction technology and allows building on virtually any soil type. Additionally, the sand cushion significantly reduces stress on the foundation’s lower section and protects it from seasonal soil heaving.