Party Wall etc. Act 1996
1996 c. 40. Notice periods, to scale above, for work to a shared wall, or a dig below next door’s foundations within 3 m, or through a 45° line from them within 6 m.
Standards
The rules we work to, named.
Every designation on this page was checked against the publisher’s own catalogue on 21 September 2026. How to treat that date.
The law
Three requirements in England and Wales.
Scotland and Northern Ireland word theirs differently.
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Every load, to the ground. 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.”
“In assessing whether a building complies with sub-paragraph (1) regard shall be had to the imposed and wind loads to which it is likely to be subjected in the ordinary course of its use for the purpose for which it is intended.”
-
The top band moves; footings go deeper. A2
Ground movement
“The building shall be constructed so that ground movement caused by—(a) swelling, shrinkage or freezing of the subsoil; or (b) land-slip or subsidence (other than subsidence arising from shrinkage), in so far as the risk can be reasonably foreseen, will not impair the stability of any part of the building.”
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A piece of wall lost; the load goes round, and down. A3
Disproportionate collapse
“The building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause.”
Key to the drawings
- Existing masonry A flat tone: everything already there, cut or seen.
- Brickwork, new Single diagonal hatch. The outer leaf, and new brickwork in elevation.
- Blockwork, new Cross-hatch, so it can never be read as brick beside it.
- Concrete Aggregate triangles and fine dots, scattered at random: foundations, slabs, padstones, lean-mix cavity fill, encasement.
- Undisturbed ground Basket weave, as a band that follows the ground line and fades out.
- Hardcore Large open zigzag, the depth of its own layer.
- Insulation board The looped line, touching both faces, inside the board outline.
- Timber, cut A box with a cross. Seen along its length, an outline only.
- Steel, cut Solid, at the section's true proportion.
- DPC Heavy dashed line, as Approved Document C draws it.
- Membrane, tray Heavy solid line: DPM, cavity tray, roof membrane.
- Load path Where the load goes, from the roof to the ground; dashed where it runs beyond the cut.
- Load marks Arrows at the symbol weight: loads down onto a member, bearing up under a foundation.
- Hidden, beyond or removed Out of the cut, beyond it, or taken out.
- Cloud Confirm on site. Never a revision mark.
- Break line The drawing stops; the building does not.
Source: The Building Regulations 2010 (SI 2010/2214), Schedule 1, Part A. Quoted in full. Crown copyright, Open Government Licence v3.0. Read Schedule 1 on legislation.gov.uk.
Guidance is not the same thing as law.
Approved Document A says so itself: “there may well be alternative ways of achieving compliance with the requirements. Thus there is no obligation to adopt any particular solution contained in an Approved Document if you prefer to meet the relevant requirement in some other way.”
Source: Approved Document A, Use of guidance. Crown copyright, Open Government Licence v3.0.
Four regimes
The guidance changes at the border. The physics does not.
Approved Document A carries its own footnote: it “gives guidance for compliance with the Building Regulations for building work carried out in England”.
Where is the house?
England
The regulationsThe Building Regulations 2010 (SI 2010/2214)
The structural guidanceApproved Document A: structure, 2004 edition
the border
England
The regulationsThe Building Regulations 2010 (SI 2010/2214)
The structural guidanceApproved Document A: structure, 2004 edition
Wales
The regulationsThe Building Regulations 2010 (SI 2010/2214)
The structural guidanceApproved Document A: structure, Welsh Government, 2004 edition
Scotland
The regulationsThe Building (Scotland) Regulations 2004 (SSI 2004/406)
The structural guidanceBuilding standards technical handbook: domestic, April 2026 edition
Northern Ireland
The regulationsThe Building Regulations (Northern Ireland) 2012 (SR 2012 No. 192)
The structural guidanceTechnical Booklet D, Structure, October 2012.
The design standards: Eurocodes with their UK National Annexes.
The same on both sides.
| Where the house is | The regulations | The structural guidance |
|---|---|---|
| England | The Building Regulations 2010 (SI 2010/2214) | Approved Document A: structure. The 2004 edition incorporating the 2004, 2010 and 2013 amendments. Its cover reads “For use in England”. |
| Wales | The Building Regulations 2010 (SI 2010/2214) | Approved Document A: structure, published by the Welsh Government. The 2004 edition incorporating the 2010 amendments. It is not the England document: the 2013 amendments say on their own first page that they apply only to England, and this edition does not carry them. |
| Scotland | The Building (Scotland) Regulations 2004 (SSI 2004/406) | Building standards technical handbook: domestic, published by the Scottish Government. The April 2026 edition, which applies to a building warrant submitted on or after 6 April 2026. |
| Northern Ireland | The Building Regulations (Northern Ireland) 2012 (SR 2012 No. 192) | Technical Booklet D, Structure, October 2012. The amendment booklets published since then cover other parts, not Part D. |
All four are free to read. Sources: legislation.gov.uk, gov.uk, gov.wales, gov.scot and buildingcontrol-ni.com, each checked on 21 September 2026.
The load
Follow the load down.
In the order the weight travels.
Not to scale; not a design.
6 of 17 standards
The roof
Rafters and struts hand the roof to the walls.
- BS EN 1990 the rules of every check
- BS EN 1991-1-1 the weight of the house
- BS EN 1991-1-3 snow
- BS EN 1991-1-4 wind
- BS EN 1995-1-1 timber
- BS 8103-3 timber, for housing
4 of 17 standards
The first floor
Joists run into the page, to walls beyond this cut.
- BS EN 1995-1-1 timber
- BS 8103-3 timber floors, for housing
With: BS EN 1990, BS EN 1991-1-1
8 of 17 standards
The outer wall
Masonry carries it down and steadies the house against wind.
- BS EN 1991-1-7 accidents
- BS EN 1996-1-1 masonry
- BS EN 1996-2 building masonry
- BS 8103-2 masonry, for housing
With: BS EN 1990, BS EN 1991-1-1, BS EN 1991-1-4, BS 8103-1
7 of 17 standards
The opening and its beam
A flush steel beam, end on here, takes the wall above. It bears out of view.
- BS EN 1993-1-1 steel
With: BS EN 1990, BS EN 1991-1-1, BS EN 1991-1-7, BS EN 1992-1-1, BS EN 1996-1-1
We design the propping too: BS 5975-2, with BS 5975-1 on site.
5 of 17 standards
The foundation
Each wall stands on its own strip.
- BS EN 1997-1 the ground
- BS EN 1992-1-1 concrete
- BS 8103-1 foundations, for housing
With: BS EN 1990, BS EN 1991-1-1
4 of 17 standards
The ground
Every load ends here.
- BS EN 1997-2 ground investigation
With: BS EN 1990, BS EN 1997-1, BS 8103-1
BS EN 1993-1-1
:2005+A1:2014
part number: does not changeedition: a fact about a date
Part numbers on top, editions underneath
Both Eurocode generations sit in the catalogue as current, so we name the part number, with the edition we checked underneath.
Design standards
The standards we design to, as they are published.
The last group is temporary works: the propping we design.
“The British Standards Institution notified the British Standards for structural design referenced in the 2004 edition of this Approved Document as withdrawn on 31 March 2010. British Standards for structural design based upon the Eurocodes were correspondingly implemented by the British Standards Institution on 1 April 2010 and it is these standards with their UK National Annexes which are now referenced in this Approved Document as practical guidance on meeting Part A requirements.”
Approved Document A, British Standards. Crown copyright, Open Government Licence v3.0.
Basis of design
The common rules the other standards sit on.
BS EN 1990
with its UK National Annex
Eurocode. Basis of structural design.
What counts as a load case, what factors are applied to it, and what the structure is then checked against. It is the reason a beam is checked twice: once for whether it is strong enough, and once for how far it bends.
Edition checked: BS EN 1990:2002+A1:2005
National Annex: NA to BS EN 1990:2002+A1:2005
The loads
Where the numbers on the left-hand side of every calculation come from.
BS EN 1991-1-1
with its UK National Annex
Eurocode 1. Actions on structures. General actions. Densities, self-weight, imposed loads for buildings.
The weight of the building itself, and the weight of everything put into it afterwards. This is the starting point for sizing any beam in a house.
Edition checked: BS EN 1991-1-1:2002
National Annex: NA to BS EN 1991-1-1:2002
BS EN 1991-1-3
with its UK National Annex
Eurocode 1. Actions on structures. General actions. Snow loads.
Snow sitting on a roof is a load like any other. It matters for a loft conversion, for a re-roof and for a flat-roofed extension tucked under a taller wall.
Edition checked: BS EN 1991-1-3:2003+A1:2015
National Annex: NA+A2:18 to BS EN 1991-1-3:2003+A1:2015
BS EN 1991-1-4
with its UK National Annex
Eurocode 1. Actions on structures. General actions. Wind actions.
Wind pushes on a house and it also lifts. Where the house stands, how exposed it is and how tall it is all change the answer, which is why a gable on an open hillside is not the same problem as the same gable mid-terrace.
Edition checked: BS EN 1991-1-4:2005+A1:2010
National Annex: NA to BS EN 1991-1-4:2005+A1:2010
BS EN 1991-1-7
with its UK National Annex
Eurocode 1. Actions on structures. General actions. Accidental actions.
Requirement A3 is the one about a building not collapsing out of all proportion to an accident. Approved Document A points to the annexes of this standard for further guidance on it.
Edition checked: BS EN 1991-1-7:2006+A1:2014
National Annex: NA+A1:2014 to BS EN 1991-1-7:2006+A1:2014
The materials
One standard per material, and a house usually touches several at once.
BS EN 1992-1-1
with its UK National Annex
Eurocode 2. Design of concrete structures. General rules and rules for buildings.
Foundations, ground beams, a reinforced concrete lintel, the slab under a new extension.
Edition checked: BS EN 1992-1-1:2004+A1:2014
National Annex: NA+A2:14 to BS EN 1992-1-1:2004+A1:2014
BS EN 1993-1-1
with its UK National Annex
Eurocode 3. Design of steel structures. General rules and rules for buildings.
The steel beam that replaces a wall, and the posts and padstones it lands on. This is the standard behind the section size written on the drawing.
Edition checked: BS EN 1993-1-1:2005+A1:2014
National Annex: NA+A1:2014 to BS EN 1993-1-1:2005+A1:14
BS EN 1995-1-1
with its UK National Annex
Eurocode 5. Design of timber structures. General. Common rules and rules for buildings.
Joists, rafters, trimmers around a new stair opening, and the new floor that goes into a loft.
Edition checked: BS EN 1995-1-1:2004+A2:2014
National Annex: NA to BS EN 1995-1-1:2004+A2:2014
Approved Document A still lists the +A1:2008 amendment, because its own list was frozen in 2013.
BS EN 1996-1-1
with its UK National Annex
Eurocode 6. Design of masonry structures. General rules for reinforced and unreinforced masonry structures.
The brick and block walls already carrying the house, and the piers a new beam is about to land on. Most of a house is masonry, so most of a house is this.
Edition checked: BS EN 1996-1-1:2005+A1:2012
National Annex: NA to BS EN 1996-1-1:2005+A1:2012
BS EN 1996-2
with its UK National Annex
Eurocode 6. Design of masonry structures. Design considerations, selection of materials and execution of masonry.
The buildable half of masonry design: what the wall is made of, and how it has to be built for the design to mean anything.
Edition checked: BS EN 1996-2:2006
National Annex: NA to BS EN 1996-2:2006
The ground
Requirement A2 is about ground movement, and this is where that gets designed.
BS EN 1997-1
with its UK National Annex
Eurocode 7. Geotechnical design. General rules.
What the ground under a foundation can carry, and what it does when it dries out, wets up or freezes. Foundation width and depth both land here.
Edition checked: BS EN 1997-1:2004+A1:2013
National Annex: NA+A2:2022 to BS EN 1997-1:2004+A1:2013
This is the clearest example on the page of an annex moving on its own: the previous annex was withdrawn on 28 February 2022 while the standard it belongs to stayed put.
BS EN 1997-2
with its UK National Annex
Eurocode 7. Geotechnical design. Ground investigation and testing.
How you find out what the ground is, rather than assuming it. Trial holes, boreholes and soil testing.
Edition checked: BS EN 1997-2:2007
National Annex: NA to BS EN 1997-2:2007
Written for housing
A house is not a small office block, and these three are written for houses.
BS 8103-1
Structural design of low-rise buildings. Code of practice for stability, site investigation, foundations, precast concrete floors and ground floor slabs for housing.
Holding a house steady sideways, and what goes on underneath it.
Edition checked: BS 8103-1:2011.
BS 8103-2
Structural design of low-rise buildings. Code of practice for masonry walls for housing.
The walls, at housing scale rather than general masonry scale.
Edition checked: BS 8103-2:2013
Approved Document A still lists the 2005 edition, for the same reason as the timber standard above.
BS 8103-3
Structural design of low-rise buildings. Code of practice for timber floors and roofs for housing.
Floors and roofs in timber, which is nearly every floor and roof in a British house.
Edition checked: BS 8103-3:2009.
Getting it built
The structure that holds the house up while the permanent structure is not there yet. Propping and needling while a wall comes out is temporary works. We design it; the builder puts it in, keeps it right and takes it out. At the end of 2024 one code of practice became two.
BS 5975-1
Temporary works. Management procedures for the control of temporary works. Code of practice.
Who is responsible for the temporary structure, who checks it, and the procedure it goes through before anyone relies on it.
Edition checked: BS 5975-1:2024.
BS 5975-2
Temporary works. Falsework: design and implementation. Code of practice.
The design side of temporary works: written for falsework, and BSI says it “can be applied to the design of other temporary works”.
Edition checked: BS 5975-2:2024.
These two replaced BS 5975:2019, which BSI withdrew on 18 December 2024 and split into the management part and the design part.
Free, and bought
Free: the law and the government guidance, at the links given. Bought: every BS and BS EN document and National Annex, from BSI. We reproduce none of their text.
How to treat this list
Checked by hand on 21 September 2026.
One clause
This is where a structural answer comes from.
“Except where strip foundations are founded on rock, the strip foundations should have a minimum depth of 0.45m to their underside to avoid the action of frost. This depth, however, will commonly need to be increased in areas subject to long periods of frost or in order to transfer the loading onto satisfactory ground.”
“The depth to the underside of foundations on clay soils should not be less than 0.75m on low shrinkage clay soils, 0.9m on medium shrinkage clay soils and 1.0m on high shrinkage clay soils, although these depths may need to be increased in order to transfer the loading onto satisfactory ground, or where there are trees nearby.”
Approved Document A, paragraph 2E4
Quoted verbatim. Crown copyright, Open Government Licence v3.0.
Statutory
Three more that catch families out.
The Construction (Design and Management) Regulations 2015
SI 2015/51. The health and safety regime over the whole project, a private house included, and where the CDM roles of client, designer, principal designer and principal contractor come from.
Building Regulations Part 2A
In England since 1 October 2023, with its own principal designer, separate from CDM’s. Where more than one contractor is, or will foreseeably be, involved and a family appoints none, “the designer in control of the design phase of the project is the principal designer”.
Source: SI 2010/2214, regulations 11C(2) and 11D(1).
Architect or builder? Send us a set.
You will get the standards named on the calculation package, and the clause reference where a number came from a published rule.
The earlier we are involved, the more of your structure is still worth optimising.
We reply within one working day.