Pouring Foundation for a Private House

The foundation is the base, the foundation, preventing the house from tilting and protecting it from ground moisture and rot.

Types of Foundations

Over centuries, three main types of foundations have become established and are most commonly used: strip, pile, and slab foundations. The choice depends first on soil type and climate conditions, and second on the builder’s financial capacity. On average, foundation construction accounts for 15–20% of the total home-building budget.

Pile foundations are recommended for heaving soils with deep winter frost penetration. Their main advantage is relatively low cost compared to other types. They are 1.5 to 2 times cheaper than strip foundations, and up to 3–5 times cheaper when installed at greater depths. However, they make it difficult to build a basement, and they are less reliable on weak-bearing soils, especially for large and heavy homes.

The last type — the most expensive — involves pouring a monolithic concrete slab under the entire future structure.

Site Preparation

A full-scale layout of the house is drawn on site. An additional 1–1.5 meters are added to the external walls, and the boundary is marked. Before digging pits, trenches, or basements, the topsoil layer with grass is removed and relocated to a garden or vegetable patch.

Right angles are carefully established during strip foundation construction using a large triangle and verified by measuring diagonals. Pits for pile foundations are conveniently prepared using a garden auger. Level is checked using a hose with glass tubes attached to both ends. Colored water is poured into the hose, and the control level is marked on stakes and transferred across the site.

Foundation depth depends on proximity to groundwater. On non-heaving soils, it usually does not exceed 70 cm. Formwork is always required. Often, wooden form panels — previously assembled and used — circulate between builders in a neighborhood or city, being resold or rented from owners.

Concrete Mix Composition

Common fillers include sand, gravel, stones, and bricks. Today, foundations are most often made of concrete and reinforced concrete. The concrete mix is prepared in a ratio of 1:3:4–5, meaning: 1 part cement, 3 parts sand, and 4–5 parts gravel or rubble (stone).

Water should be added so the mix is easy to place but not runny. Cement grade 300–400 is recommended; however, low-grade cement is rarely found in retail sales today.

Many modern builders prefer to purchase ready-mixed concrete from nearby plants. At the scheduled time, a concrete mixer truck arrives on site, and the homogeneous mix is poured directly from the hose into the prepared formwork.

To strengthen the foundation, it is reinforced. Reinforcement bars, pipe cuttings, or thick wire can be used. A reinforced foundation better resists deformation and extrusion caused by soil heaving forces.