UK Construction Standards Reference

Last reviewed: 9 September 2026

The specifications and codes of practice our calculators are built against - what each one actually covers, what it doesn't, and which calculator relies on it. Everything on this page has already been checked against the standard itself, not taken from a competitor's page or assumed from memory.

MOT Type 1 (SHW Clause 803)

The unbound granular sub-base spec behind our sub-base, gravel, shed base and patio calculators.

MOT Type 3 (SHW Clause 805)

The free-draining sub-base spec used under permeable paving and SuDS schemes.

BS 7533-102:2025

The current UK code of practice for installing modular block and flag paving.

BS 3882:2015

The UK topsoil specification, and why it excludes subsoil altogether.

Not every standard our content mentions has its own page yet. We only publish a standard here once we've verified its actual scope directly, not just repeated a citation - a shorter list we can stand behind beats a longer one we can't.