Structural & Concrete Calculators

Structural work forms the backbone of every UK building project, from domestic house extensions and garden walls to commercial foundations and reinforced concrete frames. Accurately calculating concrete volumes, brick and block quantities, and mortar mixes is essential for keeping projects on budget and avoiding material shortages on site.

In UK domestic construction, concrete is used extensively for foundations (strip footings, trench fill), floor slabs, paths, and bases. Ready-mix concrete is ordered by the cubic metre (m³) and delivered by companies such as Hanson, Cemex, and Aggregate Industries. Our concrete volume calculator helps you determine exactly how many cubic metres to order. For smaller quantities, site-mixed concrete using cement, sharp sand, and aggregate (typically in a 1:2:3 or 1:2:4 ratio by volume) is more practical. The concrete mix calculator provides the right proportions for different strength requirements.

Standard UK concrete blocks measure 440mm × 215mm × 100mm (face area 0.1 m² including mortar joints), so you need approximately 10 blocks per square metre of wall. For brickwork, standard UK bricks measure 215mm × 102.5mm × 65mm, requiring about 60 bricks per square metre in stretcher bond (half-brick wall). Our brick calculator accounts for bond pattern, wall thickness, and openings (windows and doors) to give an accurate order quantity with a configurable wastage allowance.

UK Building Regulations (Approved Document A) set out structural requirements for foundations, walls, and roofs. Foundation depth is determined by soil type, tree proximity, and building load, with NHBC Standards Chapter 4.2 providing detailed guidance. In clay soils, foundations may need to be 1m or deeper, while granular soils typically require 600–750mm minimum depth. Structural calculations for lintels, padstones, and steel beams must be carried out by a qualified structural engineer. Our lintel and padstone sizing calculators provide initial guidance, but all structural elements should be verified by a professional.

Mortar for bricklaying and blockwork is typically mixed from Portland cement and building sand at ratios of 1:4 to 1:6 depending on the application. Plasticiser (or lime) is added for workability. Pre-mixed mortar from companies like Breedon and Cemex is increasingly popular for larger projects. Concrete drying and curing times are affected by ambient temperature, humidity, and section thickness, with a general rule of 1mm per day for screeds and 7 days for concrete to reach 70% of its 28-day strength.