Reference

UK Construction Standards & Regulations

Plain-English explanations of the British Standards and Building Regulations our calculators are built on — so you can see exactly where the numbers come from.

Pavement & Paving Construction

BS 7533 is the British Standard series governing the design and construction of paving — covering bedding,...

BS EN 998-2 is the European standard for masonry mortar, classifying mortar by compressive-strength class from...

Aggregates for Concrete (Sharp Sand)

BS EN 12620 is the standard for aggregates used in concrete, including the angular sharp (grit) sand used for...

Aggregates for Mortar (Building Sand)

BS EN 13139 is the standard for aggregates used in mortar, including soft building sand whose fine rounded...

Clay Masonry Units

BS EN 771-1 is the specification for clay masonry units (bricks), defining dimensions, tolerances and...

SHW Clause 803 / 805

MOT Type 1 & Type 3 Sub-Base

MOT Type 1 (SHW Clause 803) and MOT Type 3 (SHW Clause 805) are the granular sub-base materials specified in...

Building Regs — Part H

Drainage & SuDS

Approved Document H of the Building Regulations covers drainage, including the SuDS provisions that require...

Radiator Heat Output

BS EN 442 is the European standard governing how radiator heat output is tested and published — at ΔT50 (75°C...

CIBSE Domestic Heating Design Guide

Room Heat-Loss Method

The CIBSE method is the UK heating-engineering approach to calculating room heat loss from volume, fabric...

IET Wiring Regulations

BS 7671, the IET Wiring Regulations, is the UK national standard for electrical installations — it sets the...

Building Regs — Part L

Conservation of Fuel & Power

Approved Document L sets the energy-efficiency requirements for UK buildings, including insulation standards...

Topsoil Specification

BS 3882 is the British Standard specifying requirements for topsoil quality, defining structural grades (like...

Concrete Specification

BS 8500 is the UK national standard for concrete specification and production, governing the strength grades...

Slating & Tiling for Pitched Roofs

BS 5534 is the British Standard for pitched roof design, establishing requirements for tile headlap, pitch...