BS 3882:2015
Last reviewed: 9 September 2026
What it covers
BS 3882:2015 is the UK specification for topsoil - the classification and quality requirements for material intended to support plant growth.
What it does not cover
It explicitly excludes subsoil from its scope altogether. Subsoil is the mineral layer beneath topsoil: low in organic matter and nutrients, and not classified as a growing medium at all under this specification. That's not a minor technicality - it's the reason subsoil is fine as bulk fill or for levelling beneath a topsoil layer, but should never be the final layer wherever anything actually needs to grow.
Which of our calculators rely on it
- Topsoil Calculator - the subsoil-vs-topsoil distinction is used directly in the calculator's own guidance on when subsoil is (and isn't) an appropriate substitute.