Extensions
109 sources in the library on extensions. Each one says what the document covers and what it is good for. Name a source to see which document it is and where to read it. One at a time. Page 3 of 3.
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The National Archives (legislation.gov.uk), Northern Ireland Statutory Rules
NORTHERN IRELAND, and Class A differs from England, Wales and Scotland alike. A single-storey rear extension may extend beyond the rear wall of the original dwellinghouse by no more than 4 metres for a DETACHED house or 3 metres for any other, must not exceed 4 metres in height, and must not come within 3.5 metres of a curtilage boundary with a ROAD opposite the rear wall. An extension of more than one storey is limited to 3 metres beyond the rear wall and must be at least 7 metres from the boundary opposite the rear wall, against Wales's 10.5 metres. Eaves must not exceed 3 metres within 2 metres of any boundary. A side extension must not exceed 4 metres in height or half the width of the original dwellinghouse. Class A expressly excludes ANY alteration to the roof, any deck, balcony, veranda or raised platform, any basement, any chimney, flue or soil and vent pipe, and any microwave antenna, so a Northern Ireland dormer or rooflight is not permitted development under this class. In a conservation area, World Heritage Site, AONB or National Park, cladding in stone, artificial stone, pebbledash, render, timber, plastic or tiles is excluded, as is any extension of more than one storey or over 4 metres or beyond a principal or side elevation. Condition A.3(b) requires any upper floor side-elevation window within 15 metres of a neighbouring curtilage boundary to be obscure glazed and non-opening below 1.7 metres above floor level. Northern Ireland has NO larger home extension prior approval route.
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The National Archives (legislation.gov.uk), Scottish Statutory Instruments
SCOTLAND. Schedule 3 is Scotland's equivalent of England's exempt work and diverges sharply from it. Type 1 makes any work to or in a house warrant-exempt except work that increases floor area, demolishes or alters the roof, external walls or elements of structure, adversely affects a separating wall, changes the wastewater disposal system, or is to a storey more than 4.5 metres high. Types 3 to 5 exempt a detached single-storey building over 8 and up to 30 square metres, but not one within 1 metre of the house unless it is at least 1 metre from any boundary, not one containing a fixed combustion appliance or sanitary facility, and not a swimming pool deeper than 1.2 metres; for a flat or maisonette the separation is 3 metres. Type 6 exempts heating work below 50kW solid fuel, 45kW oil or 70kW net gas, but not work on a chimney, flue pipe or hearth, nor an oil storage tank over 90 litres.
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The National Archives (legislation.gov.uk), Scottish Statutory Instruments
SCOTLAND. The instrument that sets Scotland's building standards, made under the Building (Scotland) Act 2003, and the reason England's Approved Documents do not apply north of the border. Regulation 3 exempts certain buildings and services, regulation 5 introduces the descriptions of work not requiring a building warrant, regulation 8 covers fitness and durability of materials and workmanship, regulations 9 to 12 set the building standards for construction, demolition, services and conversion, and regulation 16 provides for relaxations. Schedule 1 lists exempted buildings, Schedule 3 the warrant-exempt work and Schedule 5 the mandatory building standards that the Technical Handbooks expand.
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The National Archives (legislation.gov.uk), Scottish Statutory Instruments
SCOTLAND, and these figures contradict the England fees. Made 3 February 2026 and in force from 1 April 2026, amending SSI 2022/50. Category 2 of Table 1 sets the householder planning fee for the enlargement, improvement or other alteration of an existing dwelling at £371 for one dwelling and £742 for two or more, against England's £548 householder fee from the same date. Category 3 charges £371 for an outbuilding or other operation within the curtilage of an existing dwellinghouse ancillary to its enjoyment, and £371 for gates, fences, walls or other means of enclosure along a curtilage boundary. Regulation 3 raises the flat fee from £357 to £371, regulation 4 raises the discretionary fees from £238 to £247 and from £119 to £124, and paragraph 9(1) from £714 to £742. New dwellings are £742 each for the first 10, then £557, then £310 above 49, capped at £185,524.
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Valuation Office Agency, HMRC (GOV.UK)
Published 22 January 2016 and last updated 15 June 2026, applying to England and Wales, this is the authority that corrects two common claims. First, on rebanding after an improvement: bands are based on the open market price on 1 April 1991 in England and 1 April 2003 in Wales, and if a property has increased in size since it was first assessed it may move to a higher band when it is next sold, so an extension does not trigger an immediate rebanding of the current owner. Second, on Council Tax during works: if the property is occupied the band will not be deleted even if significant repair or renovation works are underway, and only where the property is unoccupied and either beyond repair or undergoing major works making it uninhabitable can the owner apply to have the band removed. Reproduces the full band tables: England Band A up to 40,000 pounds through Band H over 320,000 pounds; Wales Band A up to 44,000 pounds through Band I over 424,000 pounds, Wales having nine bands to England's eight. Assessments are based on size, layout, character, location, change of use and the 1991 or 2003 value, and the Valuation Office does not use property price indexes.
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Welsh Government
The Welsh route to funded adaptations, which differs from England in having a second scheme alongside the Disabled Facilities Grant. A Welsh applicant can apply for support from one or more of the ENABLE support for living independently scheme and the Disabled Facilities Grant, whereas an English applicant has the Disabled Facilities Grant alone. The listed adaptations are widening doors and installing ramps, improving access to rooms and facilities such as stair lifts or a downstairs bathroom, providing a heating system suitable for the applicant's needs, and adapting heating or lighting controls to make them easier to use. Part of the Welsh Government's Home safety, repairs and adaptation collection, with parallel guides for social housing tenants and for adapting a home before returning from hospital.
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Welsh Government (gov.wales)
The Welsh Approved Document L Volume 1, in force until 3 March 2027, and the source for Welsh window figures, which are not identical to England's. Table 10.1 sets, for new and replacement windows and roof windows, a maximum U-value of 1.4 W/(m2K) or WER Band B, with an alternative for replacements of 1.2 W/(m2K) centre pane or low-E secondary glazing, and a threshold U-value for retained windows of 3.3. Rooflights: 2.2 for new and replacement, threshold 3.8. Doors more than 60 per cent glazed: 1.4 or DSER Band C, alternative 1.2 centre pane, threshold 3.3. All other doors: 1.4 or DSER Band B, threshold 3.3. External fire doorsets as defined in Approved Document B Volume 1 may be 1.8. Transitional easements allowed timber windows at 1.6 or WER Band C and timber doors at 1.8 or DSER Band E only where a building notice, initial notice or full plans were given before 23 November 2023. Paragraph 11.35 requires an existing window or door worse than the column (c) threshold to be replaced to column (a); paragraph 11.37 states that windows and doors mean the whole unit including the frame, so replacing just the glazing or the door leaf while retaining the existing frame is not building work and does not have to meet the energy efficiency requirements, though upgrading as close as practicable is sensible; paragraph 11.38 caps the total area of windows and doors at 25 per cent of total floor area where one is enlarged or created.
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Welsh Government (gov.wales)
The Welsh Government landing page that shows which edition of Approved Document L applies in Wales and when. Two editions of Volume 1 (dwellings) sit side by side: the current edition in force until 3 March 2027 at /sites/default/files/publications/2024-05/building-regulations-approved-document-l-vol-1.pdf, and the 2026 edition in force from 4 March 2027 at /sites/default/files/publications/2026-04/building-regulations-approved-document-l-vol-1-2026.pdf. Note the date differs from England, where the 2026 edition of Approved Document L takes effect on 24 March 2027, so a note giving a single UK-wide changeover date is wrong for Wales by three weeks.
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Welsh Government (gov.wales)
WALES. A Welsh Government collection of quick guides, first published 27 October 2017 and last updated 22 March 2023, saying for each common project whether building regulations approval is needed in Wales. It covers adverts and signs, basements, biomass fuelled appliances, boilers and heating, ceilings and floors, change of use, conservatories, decking, decorations, demolition, doors and windows, drains and sewers, electrics, extensions, external walls, fascias, fences gates and garden walls, flats and maisonettes, flues, fuel tanks, garage conversion, heat pumps, hydro electricity, insulation, internal walls, kitchens and bathrooms, lighting, loft conversions, micro combined heat and power, outbuildings, patio and driveway and paving your front garden. Use it instead of the England Planning Portal common projects pages for any Welsh job.
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Welsh Government (gov.wales)
WALES. Most extensions require approval under the Building Regulations in Wales, with a limited set of exempt classes of new building and extension. The guide directs the reader to the separate Welsh quick guides for the elements an extension normally engages: doors and windows, drainage, electrics, external walls, internal walls, kitchens and bathrooms, and roofs. It confirms the Party Wall etc. Act 1996 applies in Wales. Note that a Welsh extension also triggers consequential improvements under regulation 28 as applied by the Welsh Approved Document L, an obligation England reserves for buildings over 1000 square metres.
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Welsh Government (gov.wales)
WALES. Building regulations approval is required to convert a loft or attic into a liveable space, and the guidance covers houses no more than two storeys high, with more extensive requirements for flats, maisonettes and houses over three storeys. The regulations are applied to ensure the structural strength of the new floor is sufficient, that the stability of the existing roof is not endangered, safe escape from fire, safely designed stairs to the new floor and reasonable sound insulation between the conversion and the rooms below. A liveable space includes a spare bedroom used infrequently. On boarding out for storage, existing ceiling joists tie the pitched roof members together and support the ceiling below and were not designed for significant load, so laying flooring boards over them may itself require a building regulations application, a point an England-based note on loft boarding usually treats as exempt. The Party Wall etc. Act 1996 applies in Wales as it does in England.
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Welsh Government (gov.wales)
WALES, and the householder figure contradicts both England and Scotland. In force from 1 December 2025, rounded to the nearest pound. Category 6, the enlargement, improvement or other alteration of existing dwellinghouses, is £585 where the application relates to one dwellinghouse and £820 for two or more, against England's £548 from 1 April 2026 and Scotland's £371. Category 7(a), operations including the erection of a building within the curtilage of an existing dwellinghouse for ancillary purposes, or gates, fences, walls or other means of enclosure along a curtilage boundary, is £283 in each case. Category 1 charges £667 for each dwellinghouse for new dwellings, with a £16,675 base fee band above 25 dwellinghouses and a maximum of £203,380. A non-material amendment under section 96A of the Town and Country Planning Act 1990 costs £123 for a householder application and £242 otherwise. Site visits are charged at £493 or £166 per visit depending on category.
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Welsh Government (gov.wales)
WALES. Published 20 October 2025. Confirms that Welsh planning fees changed on 1 December 2025 and now cover planning applications, amendments, deemed applications and site visits, all set out in the fee policy and fee document rather than in the England fee regulations. Some applications need no fee and others attract a reduced fee depending on type and circumstances, and paying too little makes the application invalid or delays it. Further guidance sits in the Welsh Development Management Manual, the Welsh counterpart to England's Planning Practice Guidance.
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Welsh Government (gov.wales)
WALES. First published 30 April 2014, last updated 29 May 2020. The Welsh Government's own householder permitted development landing page, hosting three documents that replace England's Planning Portal guidance for a Welsh job: Planning, a guide for householders (688 KB PDF, 2020), Permitted development for householders, technical guidance (2 MB PDF, 2018) and Householder permitted development rights, frequently asked questions (57 KB PDF, 2018). Wales retains the England-style Class A to Class H lettering of the Town and Country Planning (General Permitted Development) Order 1995 as it applies in Wales, unlike Scotland's numbered classes, but the numerical limits inside those classes have diverged from England since 2013.
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BSI (British Standards Institution)
STATUS: WITHDRAWN on 29 June 2021, superseded by BS 9251:2021. BS 9251:2014 was published 31 October 2014 and gave recommendations for the design, installation and maintenance of fire sprinkler systems in domestic and residential occupancies, covering components, water supplies, commissioning, testing and modification of existing systems, with the aim of life safety plus property protection and firefighter safety benefits; it records that residential sprinklers can cut the water used to fight a home fire by upwards of 90 per cent. This matters for loft conversion notes, where a sprinkler or misting system is sometimes offered as an alternative to a protected stair: any note citing BS 9251:2014 is quoting a withdrawn edition and should cite BS 9251:2021. Catalogue page confirms number, title, publication date, withdrawal date and scope.
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BSI (British Standards Institution)
STATUS: WITHDRAWN on 31 October 2015, superseded by BS 9991:2015 (and since by a further revision). BS 9991:2011 was published 31 December 2011 and itself superseded BS 5588-1:1990. It gave the code of practice for fire safety in residential buildings, covering dwellings, residential accommodation blocks for up to six people and sheltered and extra care housing, applying to new design and to material alterations, extensions and changes of use, across ten sections covering means of escape, stairs, firefighting access, active fire protection, construction, mechanical systems, ancillary accommodation and management. It excludes hotels, caravans, hospitals, care homes, detention facilities, hostels and houses in multiple occupation. This is the standard a loft conversion note reaches for when discussing protected stairs and escape windows, so citing the 2011 edition is citing a withdrawn one. Catalogue page confirms number, title, publication date, withdrawal date, supersession and scope.
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BSI (British Standards Institution)
STATUS: CURRENT. BS 9999:2017 was published 31 January 2017 and supersedes BS 9999:2008, which is withdrawn. It gives the code of practice for fire safety in the design, management and use of buildings, aimed at life safety for occupants and firefighters with property and business protection as secondary objectives. The 2017 revision added a design process flowchart, brought in watermist suppression systems, revised smoke and heat control guidance, added recommendations for fire curtain barriers and updated the shopping complex provisions. Crucially for a home renovation note, it EXCLUDES individual dwellinghouses, and has limited application to specialist buildings such as hospitals and places of lawful detention, so it is the wrong standard to cite for a house: use Approved Document B Volume 1 for dwellings and BS 9991 for residential buildings. Catalogue page confirms number, title, date, status, supersession and scope.
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Chartered Institution of Building Services Engineers
TM59 is the dynamic thermal modelling methodology that Approved Document O Section 2 names as its alternative to the simplified glazing and free-area route, so it is a required citation for any note about overheating. This page is for the 2026 edition, published July 2026, 39 pages, ISBN 9781912034123, and it is FREE to download at both standard and member rate, unusually for CIBSE. The critical compliance point stated on the page: TM59 (2017) is still the version required for compliance with Part O, and CIBSE recommends TM59 (2026) only for industry best practice while it discusses with the Building Safety Regulator how the updated weather files and new version might be incorporated into the Approved Documents. So a note must not tell a reader that the 2026 edition satisfies Part O. The 2026 update adds a new bedroom overheating criterion based on Loughborough University research, updated ceiling fan modelling presenting fans as an effective passive comfort solution, and mandates that all homes be tested under unconstrained conditions using 2050s weather data. TM59 applies to houses, apartments, sheltered accommodation, care homes, student accommodation, prisons and bedrooms in hotels and hospitals, and covers new dwellings and major refurbishments. The page also records that in 2026 the Climate Change Committee raised risks to buildings and communities from heat to its highest category, Critical Action needed.
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Financial Conduct Authority
The regulator's 2026 multi-firm review of the product most often sold as a home improvement loan, published 12 March 2026 and updated 13 March 2026. Establishes the market facts a finance note should cite: second charge mortgages let a homeowner borrow against equity without changing their main mortgage, they are typically less than 4 per cent of regulated mortgage sales, they tend to carry higher interest rates than first charge mortgages, and consumers mostly use them to consolidate debt rather than to fund works. Warns that these customers often carry a high level of debt so a significant proportion may have characteristics of vulnerability including low financial resilience. The FCA reviewed quality of advice, robustness of affordability assessments, the role of intermediaries, record keeping and intermediary fees, sampling firms covering over 40 per cent of second charge advice firms and around 50 per cent of second charge lenders, and found evidence of poor practices creating a risk of poor customer outcomes. Frames expectations against the Consumer Duty and the Mortgage Conduct of Business rules, and follows a 2018 Dear CEO letter to second charge lenders and a 2025 Portfolio Letter to mortgage intermediaries.
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National House Building Council
NHBC, established in 1936, is the UK's leading independent new home warranty and insurance provider and the publisher of the NHBC Standards, the technical requirements that sit alongside the Building Regulations for warranted homes. Its Buildmark warranty covers newly built or converted homes for sale, with Buildmark Choice for rental and shared ownership and Buildmark Connect for commercial space in mixed-use schemes, currently protecting around 1.2 million homes. Cite NHBC Standards where a roofing or extension note needs a workmanship benchmark stricter than the minimum in an Approved Document.
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United Utilities
A sewerage undertaker setting out its own build-over process, which is the practical authority for the consent a homeowner actually needs (the Water UK Sewerage Sector Guidance covers adoption, not build-over). The page states that United Utilities approval is required for building works within 3 metres of a public sewer or lateral drain. On access, it requires sufficient access points to the affected sewer, meaning manholes and rodding points; states that ideally buildings and extensions should not be sited where they would remove an existing point of access; and requires access points to be easily accessible and visible for use in an emergency. Where ground conditions are poor, the developer must arrange special design and construction plans so the pipe is protected from any risk of damage. On the route through building control, it explains that building control inspectors operating under the United Utilities Protocol agreement can approve build-overs that meet set criteria, and that where a proposal does not fit those criteria the inspector escalates it so United Utilities can deal with the developer directly, which is why a homeowner may find the sewer question handled inside their Building Regulations application rather than as a separate approach to the water company.
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Water UK
The Water UK page indexing the Sewerage Sector Guidance, captured on the Wayback Machine because water.org.uk returns 403 to scripted fetches. Page date published 21 April 2023. The document set comprises the main SSG (approved version 2.2, 29 June 2022, later v2b) plus Appendix B Procedures, Appendix C Design and Construction Guidance, Appendix D Minimum Information, Appendix E Model Sewer Adoption Agreement, Appendix F Levels of Service and Reporting, Appendix G Terms of Reference approved by Ofwat, and a transitional principles document, along with published local practice notes from Anglian Water, Southern Water, Thames Water and Wessex Water on sewage pumping stations and, for Thames Water, on easements. Section 1.1 of the SSG states that it is the guidance which companies holding an instrument of appointment as sewerage undertakers under sections 6 or 7 of the Water Industry Act 1991 recommend Ofwat enables under its Code for Adoption, which came into effect on 13 November 2017, and that it contains a draft Model Sewerage Adoption Agreement. Sections 1.2.1 to 1.2.3 confirm sewerage companies are obliged by the Code to comply once Ofwat approves it, that failure may result in investigation and sanction by Ofwat, that it applies to infrastructure covered by a section 104 Water Industry Act agreement, and that it applies to companies operating wholly or mainly in England. IMPORTANT SCOPE POINT: the SSG governs the ADOPTION of new sewerage assets, not the separate build-over-a-sewer consent a homeowner needs, so do not cite it as the authority for a build over agreement.
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Considerate Constructors Scheme
A route most UK renovation articles never mention: what a neighbour affected by building work can actually do. The Scheme records all concerns, comments, compliments or complaints about a registered activity regardless of source. Once a concern is reviewed and found to relate to the Code of Considerate Practice, the Scheme informs the activity designated contact, usually the site manager or company contact, and may highlight the relevant parts of the Code. If the person raising it gives permission, their name and contact details are shared so the contact can work with them directly, particularly where compensation may be involved or where they have already been in contact with the site; if permission is not given, the Public Support team liaises on their behalf and the matter is handled confidentially. Crucially, if the construction activity is NOT registered with the Scheme, the Scheme will still contact the relevant organisation and attempt to mediate between the parties, but cannot progress the concern if that organisation does not respond. Contact is by freephone 0333 049 4600 in the UK, 1800 939 109 in the Republic of Ireland, or publicsupport@considerateconstructors.com.
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Considerate Constructors Scheme
The code a registered contractor commits to, and the standard a homeowner or neighbour can measure a builder against. Registering an organisation, contractor or supplier with the Scheme is a commitment to observe and implement the Code, and the Code applies equally to all registered activities regardless of size, type or location. It has three sections. Respect the community: courteous and respectful language and appropriate behaviour in and around the activity; providing a safer environment, preventing unnecessary disturbance and reducing nuisance for the community; and proactively maintaining effective community engagement. Care for the environment: prioritising environmental issues to protect the natural environment and minimise negative impacts; optimising the use of resources including minimising carbon throughout the value chain; and engaging with the community to improve the local environment. Value the workforce: creating a supportive, inclusive and healthy workplace. Registration also means agreeing to be visited and scored by a Scheme Monitor, with conformance recognised through Certificates of Performance, Records of Performance and the Leading Lights Awards, and optional paid advisory visits available.
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Glass and Glazing Federation
The GGF is the UK industry body for glass and glazing, representing companies across glazing, fenestration and related trades. It runs a Technical Library and Technical Hub with guidance on windows, doors, conservatories and specialist glazing, a searchable directory of member companies, and a Member Complaint Service for disputes with a member firm. It sits alongside and links to FENSA for windows and doors Building Regulations compliance, BFRC for window energy ratings, and RISA certification. Approved Document L names the GGF as the source of the methods for calculating Window Energy Rating and Doorset Energy Rating, which is why this body matters for a note quoting WER bands.
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Structural Timber Association
The STA is the trade body representing structural timber manufacturers and specifiers, working to increase structural timber specification and to influence legislation and regulation in the sector. Its flagship technical document is the Volume 1 Pattern Book, covering the fire resistance performance of a range of commonly used structural timber walls and floors and explaining component build-ups and the modifications that are permitted. The Pattern Book is freely available to designers and specifiers but may only be used on projects where the timber frame, SIPs or mass timber elements are supplied by an STA member manufacturer, a limitation worth stating if a note points a reader to it. The STA also runs the STA Assure Quality Assurance Scheme for member competency and publishes fire research on timber frame and mass timber systems.
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Northern Ireland Water
NORTHERN IRELAND. NI Water requires a Building Over or Near a Public Sewer Agreement, and its conditions go beyond the England build-over agreement. Drawings must be at a scale of 1:100 or greater and colour code existing public sewers, foul in red, storm in green and combined in magenta, with private drainage in black, plus longitudinal sections showing pipe size, gradient, material, manholes and invert and cover levels to Ordnance Datum Belfast. Where building over the sewer, ONLY SUSPENDED CONCRETE FLOORS are permissible if a concrete floor is proposed. A method statement is required whether or not the pipe is being replaced, and NI Water may require a Structural Engineer's Report at the developer's expense. Critically, where there is any loan or mortgage on the property the LENDER MUST SIGN the agreement before it is returned, and the applicant must hold and provide current home insurance including buildings cover. No work may start until the agreement is authorised and returned. Applications are triaged before payment is requested, and third and subsequent applications on the same sewer leg attract a discount under the Scheme of Charges.
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Scottish Water
SCOTLAND. Scottish Water is a single public corporation covering all of Scotland, so there is no regional water and sewerage company to approach as in England, and no Thames Water or Severn Trent style build-over agreement process. The page sets out the Single House Connections route for anyone constructing a new domestic property, renovating an existing property, needing a temporary connection or a building water supply, or converting from a private water supply to the public water or sewer network, and stresses planning utility connections at the earliest stage. The process runs in four published stages, Preparing, Applying, Constructing and Completing, supported by a downloadable Single House Connections Guidance document that also covers converting from a private to a public water supply. Contact is 0800 0778 778, 24 hours a day.
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Timber Media
A timber trade press report reproducing TDUK's launch announcement; it confirms TDUK was formed by merging the TTF and TRADA and combines TRADA's guidance library. Tier 6 because TDUK's own site cannot be fetched.