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 UK paving construction standard series for structural design (101), installation (102), and...

BS EN 998-2 is the European specification for masonry mortar, covering designed and prescribed site-mixed...

Aggregates for Concrete (Sharp Sand)

BS EN 12620 specifies UK concrete aggregates, defining size grading, fines limits, and weather resistance for...

Aggregates for Mortar (Building Sand)

BS EN 13139 specifies UK mortar aggregates, covering soft building sands used for workable blockwork and...

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 (Clause 803) and Type 3 (Clause 805) are granular sub-base standards for load-bearing and...

Building Regs — Part H

Drainage & SuDS

Approved Document H of the Building Regulations covers drainage and SuDS rules requiring on-site surface water...

Radiator Heat Output

BS EN 442 is the European standard for testing and publishing radiator heat outputs at Delta T50 (mean water...

CIBSE Domestic Heating Design Guide

Room Heat-Loss Method

The CIBSE method is the UK standard for calculating room heat loss from volumes, U-values, exposure, and...

IET Wiring Regulations

BS 7671 (IET Wiring Regs) sets UK rules for selecting domestic electrical cable sizes based on current,...

Building Regs — Part L

Conservation of Fuel & Power

Approved Document L sets UK building energy efficiency limits, including fabric U-value targets and 270mm loft...

Topsoil Specification

BS 3882 is the British Standard for traded topsoil, defining multipurpose and specific-purpose soil grades, pH...

Concrete Specification

BS 8500 is the UK national standard for specifying concrete, complementing the European standard BS EN 206 —...

Slating & Tiling for Pitched Roofs

BS 5534 is the British Standard code of practice for pitched roof tiling and slating, covering headlaps,...