ProjectCalcHow to use this library
- It is guidance, not advice. These pages summarise published rules so you can plan. They are not a building-control decision, and they are not professional or structural advice.
- Every figure has a source. Each page names the primary document it came from — an Approved Document, an Act or Order on legislation.gov.uk, or a named British Standard — and the date the source was read. A link to the source is printed at the foot of each page.
- If a number could not be verified, it is not published. Where we could not read the primary text of a standard, the page says so rather than paraphrasing from memory or from another website.
- Scope is England. The approved documents and the planning Order described here apply to England. Scotland, Wales and Northern Ireland have their own regimes — see the note at the bottom of this page.
Building regulations — the Approved Documents
Approved Documents are the Government's guidance on ways to meet the Building Regulations 2010. They are not the law themselves: the requirement is in Schedule 1 to the Regulations, and an Approved Document describes a way of satisfying it. The nine most relevant to the work these calculators cover:
| Part | Subject | What it covers here |
|---|---|---|
| A | Structure | Loading, ground movement, disproportionate collapse — and the Eurocodes it sends design to. |
| B | Fire safety | Volume 1 covers dwellings: lining classes, fire resistance ratings, boundary distances for walls and roofs. |
| C | Damp and site preparation | Damp-proof course height, cavity and weep-hole rules, ground floors and suspended floors. |
| E | Resistance to sound | The decibel targets for separating walls and floors, and for internal walls and floors. |
| H | Drainage and waste disposal | Soakaway sizing and separation, percolation testing, drain sizes and gradients. |
| K | Protection from falling | Guard heights of 900 mm and 1100 mm, the 600 mm trigger, and the opening-window rule. |
| L | Energy and U-values | The limiting U-values for new dwellings, and for new elements in existing dwellings. |
| M | Access to dwellings | Clear opening widths, corridor widths, kitchen clearances and minimum worktop lengths. |
| P | Electrical safety | The three categories of notifiable work, and the special location around a bath or shower. |
British and EN standards the quantities rest on
Some of what a calculator produces is governed by a standard rather than by a building regulation — and in several cases the approved document itself sends you to that standard. These are the ones we checked against the primary sources:
| Standard | What it covers | Page |
|---|---|---|
| BS 8500 and BS EN 206 | How concrete is specified — the mix designations the regulations point at. | Read |
| BS 5628-3 and BS EN 1996 | Designing with masonry: what a wall can carry, and what code of practice covers. | Read |
| BS 3882 | Topsoil as a specification, not a bag volume. | Read |
| BS EN 752 | Drain and sewer systems outside buildings — when the standard takes over from Part H. | Read |
| BS 8215, BS 8102, BS 5250 | Damp-proof courses, water from the ground, and condensation — three different problems. | Read |
| BS EN 13501-1 | How to read a fire class such as B-s3, d2. | Read |
| BS 7671 | The Wiring Regulations, which Part P points at. | Read |
The edition the regulation cites, and the current edition
An approved document names the edition of a standard that existed when it was written, and that edition is often no longer current — or has been withdrawn entirely. Presenting a superseded edition as if it were current is exactly the kind of quiet error this library is built to avoid, so every standard named anywhere in it is listed below with both: the edition the regulation cites, and the edition BSI catalogues today.
| Standard | Title as published | Edition cited by the approved document | Current edition (BSI) |
|---|---|---|---|
| BS EN 206-1 | Concrete — Specification, performance, production and conformity. Part 1: Performance, requirements, factory production control and assessment criteria for individual values | BS EN 206-1 — cited by Approved Document C as "BS EN 206-1 Method of specifying and guidance for the specifier" and by Approved Document H as "BS EN 206-1:2000" | BS EN 206-1:2026 — Current (31 March 2026) |
| BS EN 206-2 | Concrete — Specification, performance, production and conformity. Part 2: Conformity assessment and certification | Not cited by an approved document on this site | BS EN 206-2:2026 — Current (31 March 2026) |
| 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 5628-3 | Code of practice for use of masonry — Materials and components, design and workmanship | BS 5628-3:2001 — cited by Approved Document C | None. Every part of BS 5628 (1978–2005) is Withdrawn. The current UK guidance is PD 6697:2019, Recommendations for the design of masonry structures to BS EN 1996-1-1 and BS EN 1996-2 — Current |
| 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 |
| BS 3882 | Specification for topsoil | BS 3882:1994 — cited by Approved Document C | BS 3882:2015 — Current (30 April 2015) |
| BS EN 752 | Drain and sewer systems outside buildings. Sewer system management | BS EN 752-4:1998 — cited by Approved Document H, which also cites BS EN 752 Parts 3 and 6 | BS EN 752:2017 — Current, Under Review (the part-numbered structure is gone) |
| BS EN 1295-1 | Structural design of buried pipelines under various conditions of loading — General requirements | BS EN 1295 — cited by Approved Document H with no edition given | BS EN 1295-1:2019 — Current |
| BS EN 1610 | Construction and testing of drains and sewers | BS EN 1610 — cited by Approved Document H with no edition given | BS EN 1610:2015 — Current, Under Review |
| BS 8215 | Code of practice for design and installation of damp-proof courses in masonry construction | BS 8215:1991 — cited by Approved Document C | BS 8215:1991 — Current (28 February 1991) |
| BS 8102 | Protection of below ground structures against water ingress. Code of practice | BS 8102:1990 — cited by Approved Document C as "Code of practice for protection of structures against water from the ground" | BS 8102:2022 — Current (31 March 2022). Note the title has changed as well as the edition |
| BS 5250 | Management of moisture in buildings. Code of practice | BS 5250:2002 — cited by Approved Document C as "Code of practice for the control of condensation in buildings" | BS 5250:2021 — Current |
| BS EN ISO 13788 | Hygrothermal performance of building components and building elements — Internal surface temperature to avoid critical surface humidity and interstitial condensation. Calculation methods | BS EN ISO 13788:2002 — cited by Approved Document C | BS EN ISO 13788:2012 — Current |
| BS 8104 | Code of practice for assessing exposure of walls to wind-driven rain | BS 8104:1992 — cited by Approved Document C | BS 8104:1992 — Current, Under Review |
| BS CP 102 | Code of practice for protection of buildings against water from the ground | BS CP 102:1973 — cited by Approved Document C | CP 102:1973 — Current (catalogued without the BS prefix) |
| BS 6180 | Barriers in and about buildings. Code of practice | BS 6180 — cited by Approved Document K with no edition given | BS 6180:2011 — Current, Under Review |
| BS EN 1991-1-1 | Eurocode 1. Actions on structures — Specific weight of materials, self-weight of construction works and imposed loads for buildings | BS EN 1991-1-1:2002 with its UK National Annex — cited by Approved Document K | BS EN 1991-1-1:2025 — Current, Under Review. BSI currently lists both the 2002 and 2025 editions as Current, so a designer needs to check which the project is being designed to |
| PD 6688-1-1 | Recommendations for the design of structures to BS EN 1991-1-1 | PD 6688-1-1:2011 — cited by Approved Document K | PD 6688-1-1:2011 — Current (31 May 2011) |
| BS EN ISO 717-1 | Acoustics. Rating of sound insulation in buildings and of building elements — Airborne sound insulation | BS EN ISO 717-1:1997 — cited by Approved Document E | BS EN ISO 717-1:2020 — Current, Under Review |
| BS EN ISO 717-2 | Acoustics. Rating of sound insulation in buildings and of building elements — Impact sound insulation | BS EN ISO 717-2:1997 — cited by Approved Document E | BS EN ISO 717-2:2020 — Current, Under Review |
| BS EN ISO 140-3 | Acoustics. Measurement of sound insulation in buildings and of building elements — Laboratory measurement of airborne sound insulation of building elements | BS EN ISO 140-3:1995 — cited by Approved Document E | Not verified in this pass — we checked the status of the cited edition but did not confirm its replacement, so no current edition is stated here |
| BS EN 13501-1 | Fire classification of construction products and building elements — Classification using data from reaction to fire tests | BS EN 13501-1 — cited by Approved Document B with no edition given | BS EN 13501-1:2018 — Current (as BS EN 13501-1:2018 - TC, 31 January 2019). BS EN 13501-1:2007+A1:2009 is Withdrawn |
| BS EN 15102 | Decorative wallcoverings. Roll form | BS EN 15102 — cited by Approved Document B with no edition given | BS EN 15102:2019 — Current (30 June 2019). BS EN 15102:2007+A1:2011 is Withdrawn |
| BS 7671 | Requirements for Electrical Installations. IET Wiring Regulations | BS 7671:2008 incorporating Amendment No 1:2011 — cited by Approved Document P | BS 7671:2018+A4:2026 — Current (15 April 2026) |
Source: BSI catalogue records (title, designation, status and date) read at knowledge.bsigroup.com on 22 September 2026. The “edition cited” column is read from the approved document itself, not from BSI.
Planning permission
Planning is a separate regime from building regulations, and permitted development rights are granted by the Town and Country Planning (General Permitted Development) (England) Order 2015. The hub page covers outbuildings and sheds, decking, hard surfaces and driveways, fences and walls, and extensions — plus the situations where permitted development does not apply at all, including flats, conservation areas, listed buildings and article 4 directions.
Do I need planning permission? →
The calculators
Every calculator carries a short "Regs & planning" block listing the two to four rules that genuinely apply to that tool, each linking back here.
Scope, and the rest of the United Kingdom
The building regulations, approved documents and planning rules described in this library apply to England. GOV.UK marks the documents themselves "for use in England", and the permitted development Order is made for England.
The other nations of the UK have their own arrangements, with their own documents and their own limits:
- Wales — the Welsh Government publishes its own approved documents: Building regulations: approved documents (GOV.WALES).
- Northern Ireland — the Department of Finance publishes Technical Booklets in place of approved documents: Building Regulations Technical Booklets.
- Scotland — Scotland has its own building regulations rather than the England approved documents, and the Scottish Ministers issue guidance for them. That much is verifiable from the Building (Scotland) Act 2003, section 4: “The Scottish Ministers may issue guidance documents for the purpose of providing practical guidance with respect to the requirements of any provision of building regulations.” The current Scottish guidance is published by the Scottish Government, but its site could not be reached from the environment used to check these pages, so we have not linked it, and we quote no Scottish figure anywhere in this library.
Do not carry a figure from one nation to another. The England figures on this site are England figures.
What we deliberately left out
This library does not claim to cover everything, and a few things commonly written about elsewhere are absent on purpose:
- The numbers inside a paid standard. Every standard named in this library has had its title, current edition and status read from the BSI catalogue, and the edition each approved document cites has been read from the document itself — both are in the table above. What we have not done is reproduce the numeric content inside those standards: grading limits, declared values, design factors. That text sits behind a paywall and we could not read it, so it is not on this site. Where a standard is material to a calculator but is not cited by any approved document we checked — for example the paving construction series, or the plasterboard and plaster product standards — we have not built a page for it rather than build one we cannot source. That is a gap, and it is stated as a gap.
- Any figure that turns on the facts of a particular property. Ground conditions, exposure, existing construction and local policy all change answers. Those questions belong to a designer or your building control body.
- A height at which decking becomes permitted development. The Order excludes a raised platform from the classes that would otherwise cover it and does not provide a height that brings it back. We have not invented one.
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 Documents collection — current editions and publication dates for England — GOV.UK, checked 22 September 2026.
- Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended) — legislation.gov.uk, checked 22 September 2026.
- BSI catalogue (“BSI Knowledge”) — current edition, title and status for every standard named in this library — knowledge.bsigroup.com, checked 22 September 2026.
- Building (Scotland) Act 2003, section 4 (guidance documents for purposes of building regulations) — legislation.gov.uk, checked 22 September 2026.
- Building Regulations 2010 (as amended) — legislation.gov.uk, 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.