ProjectCalcWhat Part A actually requires
Approved Document A (2013 edition) sets out three requirements from Schedule 1 to the Building Regulations 2010:
- A1 — Loading. "The building shall be constructed so that the combined dead, imposed and wind loads are sustained and transmitted by it to the ground: (a) safely; and (b) without causing such deflection or deformation of any part of the building, or such movement of the ground, as will impair the stability of any part of another building."
- A2 — Ground movement. The building must be constructed so that ground movement caused by swelling, shrinkage or freezing of the subsoil, or by land-slip or subsidence, will not impair the stability of any part of the building, so far as the risk can reasonably be foreseen.
- A3 — Disproportionate collapse. The 2010 amendments removed the five-storey application limit, bringing all buildings within the scope of A3.
Note what A1(b) adds. It is not only your building that has to stay safe: the work must not move the ground in a way that takes the stability out of a neighbour's building. That sentence is why a deep excavation near a boundary — a retaining wall, a soakaway, a big footing — is a structural question and not just a digging question.
It is a signpost, not a design code
The document is explicit that compliance is met "by following the recommendations given in the documents listed in Section 1 or by adopting the guidance in Sections 2-4". The sections are:
- Section 1 — codes, standards and other references for structural design and construction, relevant to all building types.
- Section 2 — sizes of structural elements for certain residential buildings and other small buildings of traditional construction.
- Section 3 — support and fixing of wall cladding.
- Section 4 — guidance where roofs are to be re-covered as a material alteration.
Section 1 is the important one for anyone sizing a member. The design route is the Eurocode family: BS EN 1990 (basis of structural design), the BS EN 1991 actions series, and the material codes — BS EN 1992 for concrete, BS EN 1993 for steel, BS EN 1995 for timber and BS EN 1996 for masonry — each read with its UK National Annex. So when a member size matters, the answer comes from a Eurocode calculation, not from this document.
Working on an existing building
Section 4 deals with re-roofing as a material alteration. The principle is that the structure should be checked so that, on completion, the building is not less compliant with Requirement A1 than the original building was. The document sets a trigger for a "significant change in roof loading": when the loading on the roof is increased by more than 15%. It also notes that consideration might be given to whether the roof covering being replaced is the original as-built covering.
For a job at garden scale the same principle is what matters: adding weight, or removing material that was carrying load, is the point at which the structure needs looking at rather than assuming.
What this changes about the build
- Footings and slabs. Depth and width are a design outcome, not a shopping decision. The ground conditions and what the slab carries come first.
- Close to a boundary. A1(b) is the reason a neighbour's interests enter a structural calculation.
- Two-storey or load-bearing masonry. This is where you need a designer, not a rule of thumb.
- Garden outbuildings. Many are exempt from building regulations entirely under Schedule 2 to the Building Regulations 2010 — but that exemption is about whether the regulations apply, not about whether the thing needs to stand up.
The editions these documents cite
These are British and European standards this approved document names. The edition column is the one the document itself cites; the last column is what BSI catalogues today (22 September 2026). Where the two differ, the document is citing an edition that has since been replaced or withdrawn — that is normal for an approved document, and it is why the current edition is listed beside it rather than instead of it.
| Standard | Title as published | Edition cited by the approved document | Current edition (BSI) |
|---|---|---|---|
| BS 8500-1 | Concrete. Complementary British Standard to BS EN 206 — Method of specifying and guidance for the specifier | BS 8500-1:2006+A1:2012 — cited in Approved Document A, Section 1 | BS 8500-1:2023 — Current (30 November 2023) |
| BS 8500-2 | Concrete. Complementary British Standard to BS EN 206 — Specification for constituent materials and concrete | BS 8500-2:2006+A1:2012 — cited in Approved Document A, Section 1 | BS 8500-2:2023 — Current (30 November 2023) |
| BS EN 1996-1-1 | Eurocode 6. Design of masonry structures — General rules for reinforced and unreinforced masonry structures | BS EN 1996-1-1:2005+A1:2012 — cited in Approved Document A, Section 1 | BS EN 1996-1-1:2022 — Current (with UK National Annex NA to BS EN 1996-1-1:2022, also Current). An A1 amendment was in draft in April 2026 |
| BS EN 1996-2 | Eurocode 6. Design of masonry structures — Design considerations, selection of materials and execution | BS EN 1996-2:2006 — cited in Approved Document A, Section 1 | BS EN 1996-2:2024 — Current. An A1 amendment was in draft in April 2026 |
Source: BSI catalogue records read at knowledge.bsigroup.com on 22 September 2026. Each title, designation, status and date in the last two columns was read from the BSI catalogue page for that standard.
Last verified 22 September 2026. Every requirement quoted on this page was read from the primary source listed below on that date, not from a summary. If a figure could not be confirmed in the primary source it is not on this page.
Where these figures come from
- Approved Document A: Structure, 2013 edition (Requirements A1, A2 and A3; Sections 0-4) — GOV.UK publications, "Structure: Approved Document A", checked 22 September 2026.
- Approved Documents collection (index and editions) — GOV.UK, checked 22 September 2026.
- Building Regulations 2010, Schedule 2, Classes 6 and 7 (exempt buildings and work) — legislation.gov.uk, checked 22 September 2026.
- BSI catalogue (“BSI Knowledge”) — product record for each standard listed above: title, current edition and status — knowledge.bsigroup.com, checked 22 September 2026.
Guidance only, not advice
This page is a plain-English summary of published regulations and standards, written to help you plan a job. It is not professional advice, it is not a substitute for the actual document, and it is not a building-control decision.
Building regulations are enforced by your local authority (or an approved inspector) and the facts of a particular job can change the answer. Confirm with your local building control before you start work, and where a job is structural, get it designed by a suitably qualified person. If this page and the source document disagree, the source document wins.