Retaining wall

What the system calculates

You enter the wall type, length and retained height — measured from the lower ground. The system calculates excavation, base gravel, drainage (gravel, geotextile and pipe) and the wall itself:

- blocks by face area;

- gabion baskets in layers and stones;

- L elements by height;

- cast-in-place concrete and formwork;

- or timber sleepers.

Quantities follow manufacturer rules and prices are October 2026 market data. The base width, embedment and reinforcement are chosen by a structural engineer — the generator does not calculate them.

Group and permits

A retaining wall is an engineering structure (STR 1.01.03 p. 4.6). Under Annex 5 Table 2 row 3.2:

- from 0.2 to 1 m — group I, no permit;

- from 1 to 2 m — group II: in a city, protected and heritage areas a permit and a simplified design are needed;

- taller than 2 m — a non-special structure: a design, permit and ground investigation are needed everywhere.

A fence on the wall is assessed separately, from the wall top, and the structure group follows the worse parameter.

Neighbour, water and trees

The neighbour's consent is needed if the wall stands on the boundary or its height above the ground at the boundary is greater than the distance to it (STR 1.05.01 Annex 7 p. 2).

Draining surface water onto a neighbouring plot is prohibited (STR 2.02.09 p. 9.5.2); from 2027 only with the neighbour's consent. A tree must grow at least 3 m from the wall toe.

Without drainage water builds up behind the wall. An unreinforced block wall in manufacturer tables reaches only 0.4–0.9 m (in clay), so for a taller wall or cars above it the system suggests an engineer.