Which Building Regulations route does your project need, and who holds the duties?

What this route finder is doing

It follows the Building Regulations 2010, as they apply in England, in the order they apply (SI 2010/2214). It does not cover higher-risk buildings, the tall buildings for which the Building Safety Regulator is in charge of building control.

1. Is it building work, and is it exempt? The Building Regulations apply to building work: putting up or extending a building; changes that affect a building's structure or fire safety, among other things (a material alteration); the work needed when a building is put to certain new uses (a material change of use); new services and fittings such as windows, doors, drainage and electrics (controlled services and fittings); and more (regulation 3). Some buildings are taken out altogether (regulation 9 and Schedule 2). A detached single-storey building up to 30 m² with no sleeping accommodation is exempt if it is at least 1 m from the boundary of its curtilage, the land that goes with it, or constructed substantially of non-combustible materials, such as brick, block, stone, concrete or metal; so is any detached building up to 15 m² with no sleeping accommodation (Class 6). So is a conservatory, porch, covered yard, covered way, or carport open on at least two sides, added at ground level and up to 30 m², if its glass meets the safety glazing rules in Part K (Class 7). Power or water from the house still brings in the electrical safety rules in Part P and some of the water rules in Part G (regulation 9(2) and (3)). A conservatory or porch opened up to the house, or heated from it, comes under the energy efficiency rules (regulation 21(4)).
2. Can a registered installer sign it off? Installers registered with a competent person scheme can sign off certain kinds of work themselves, and when they do, no notice to building control is needed (regulation 12(6)(a) and Schedule 3): replacement windows, rooflights and doors (paragraph 10), bathrooms with no work to shared or underground drains (paragraph 12), electrical work in homes (paragraph 8) and more. The installer gives the occupier a certificate and tells building control within 30 days of finishing (regulation 20(3)). Electrical work needs a notice only for a new circuit, a replacement consumer unit (fuse box) or work in a special location, the zone around a bath or shower (regulation 12(6A)). Like-for-like replacements on the rules' list of minor work need no notice at all (Schedule 4), and where the work is only of that kind, the client's own legal duties do not apply (Part 2A; regulation 11P).
3. Must the council decide on drawings first? With the council, a full plans application, which gets a decision on the drawings before you build, is compulsory in three cases: where the fire safety law for workplaces and buildings with two or more homes (the Fire Safety Order) applies to the building, now or after the work (regulation 12(3)); where a new building fronts a private street, one the council does not maintain (regulation 12(4)); and where the work is over or next to a sewer on the sewer map, so the rule on building over sewers applies (Schedule 1, paragraph H4; regulation 12(5)). Otherwise you choose a building notice, which tells the council about the work with no drawings to decide on, or full plans (regulation 12(2)). Or a registered building control approver, the private alternative to the council, takes the work on through an initial notice (Building Act 1984, section 47). The council's rules on building notices and full plans (regulation 12) do not apply to work under an initial notice in force (regulation 19).
4. How long does each step take? The council must decide a full plans application within five weeks of receiving it, or a longer period agreed in writing (regulation 14A(6)). Before October 2023 the Building Act allowed an extension to two months at most; that cap has gone. A building notice gets no decision on plans (regulation 13(4)) and lapses if work has not started within three years (regulation 13(5)). With the council, work may start once you have told it you are about to start (a notice of intention to start) and two days have passed since the end of the day you told it (regulation 16(1)). The Regulations do not count Saturdays, Sundays or bank and public holidays as days (regulation 2), so this and the other periods in days are working days. With an approver, the council has five working days to reject the initial notice, and you tell the approver at least two working days before starting (SI 2024/110, regulations 6(4) and 15(1)). You tell the council the work is finished (the completion notice) within five days of finishing (regulation 16(4)), and the council's completion certificate is due within eight weeks of it (regulation 17(2)).
5. What if the work is already done? The council can sign off work done without approval, if it was carried out on or after 11 November 1985, with a regularisation certificate (regulation 18(1)). It may ask for work to be opened up and tested (regulation 18(3)). The certificate is evidence, but not conclusive evidence, that the work complies (regulation 18(6)).
6. Who holds the duties? The Building Regulations give legal duties to the client, the person or business having the work done, and to two roles: the principal designer, who plans, manages and monitors the design work, and the principal contractor, who does the same for the building work (Part 2A). Where there is, or will foreseeably be, more than one contractor, the client appoints both in writing (regulation 11D(1)). A homeowner's client duties pass to the contractor, or with more than one contractor to the principal contractor, or to the principal designer by written agreement (regulation 11C(1)). If a homeowner appoints nobody, the designer in control of the design phase is the principal designer and the contractor in control of the construction phase is the principal contractor (regulation 11C(2)). A business client that fails to appoint carries those duties itself until it does (regulation 11D(5)); that does not apply to a homeowner (regulation 11C(3)). With one contractor, that contractor is the principal contractor, and the designer, or the lead designer the designers agree in writing, takes the principal designer duties (regulation 11D(6) and (7)). Each role's own duties are set out in the rules (regulations 11M and 11N). The CDM principal designer, under the Construction (Design and Management) Regulations 2015, is a separate legal appointment, for health and safety in the pre-construction phase: one organisation can hold both roles only if it is appointed to both and competent for both. Check the CDM role with ClearCDM's tool.