Class 7 of Schedule 2 to the Building Regulations 2010 exempts the extension of a building by a conservatory, porch, covered yard or covered way at ground level where the floor area does not exceed 30 square metres, provided any glazing meets the specified safety requirements.

What Class 7 says

Regulation 9(1) of the Building Regulations 2010, which the legislation marks as applying in England and Wales, says the Regulations do not apply to the erection of any building or extension of a kind described in Schedule 2, or to work on such a building if it remains one after the work. Class 7 in Schedule 2 describes the extension of a building by the addition at ground level of a conservatory, porch, covered yard or covered way, or a carport open on at least two sides, where the floor area of the extension does not exceed 30 square metres.

The exemption has a condition for glazing. For a conservatory or porch that is wholly or partly glazed, the glazing must satisfy the requirements of Schedule 1 that Class 7 identifies, which concern the safety of glazing. Class 7 is limited to extensions at ground level, so an upper-storey addition is outside it, and an extension above 30 square metres is not within the exemption.

Electrics: Part P still applies

Regulation 9(3) says the requirements of Part P of Schedule 1 apply to any extension within Class 7 that receives its electricity from a source shared with or located inside a dwelling. Approved Document P repeats the point, noting that conservatories, porches, domestic greenhouses, garages and sheds that share their electricity with a dwelling are not exempt from Part P. Any new circuit in a conservatory is therefore notifiable, and the work needs certifying.

Water supplies

Regulation 9(2) applies the requirements of paragraphs G1 and G3(2) and (3) of Schedule 1, dealing with cold water supply and hot water safety, to any extension in Class 7 that receives a cold or hot water supply from a source shared with or located inside any building that is not itself of a kind described in Schedule 2. A conservatory kitchenette or sink connected to the house supply would therefore trigger these requirements.

Gas and other rules

Exemption from the Building Regulations does not remove other legal duties. The Welsh edition of Approved Document J notes that Schedule 2 exempts classes of buildings from all Building Regulations requirements, including those in Part J, but that the Gas Safety (Installation and Use) Regulations still apply to exempt buildings. A gas appliance or flue in a conservatory is therefore still subject to gas safety rules.

The exemption also has nothing to say about planning permission, which is decided under a separate system, or about private rights such as covenants.

If the conservatory is not exempt

Where a conservatory falls outside Class 7, the Regulations apply in full. The Welsh edition of Approved Document J explains that in almost all cases of new building work a building control body must be notified in advance, with two exceptions: work carried out by a person registered with a competent person self-certification scheme, and work listed as not notifiable in Schedule 4. It adds that competent person schemes let registered installers self-certify that work complies and that the occupier must then receive a compliance certificate within 30 days of completion.

Checking the position

Because Class 7 depends on floor area, level, glazing and services, the practical step is to measure the floor area of the proposed extension and list what will connect to the house: electrics, water, heating and gas. If any of those connect, some requirements remain, and if the conservatory exceeds 30 square metres or is not at ground level, the full Building Regulations apply and building control needs to be involved.

FAQs

Does a 25 square metre conservatory need building regulations approval?

If it is a ground-level conservatory within Class 7 it is exempt from the Regulations generally, but Part P applies if it shares the house electricity supply, and the glazing condition and water provisions can also apply.

Does the exemption cover a conservatory of 35 square metres?

No. Class 7 applies where the floor area of the extension does not exceed 30 square metres.

Does the same exemption apply in Scotland?

No. Scotland uses building warrants and its own Technical Handbook, and this guide covers England and Wales.

Bottom line

Class 7 exempts a ground-level conservatory of up to 30 square metres from most Building Regulations, provided the glazing meets the specified safety requirements, but regulation 9 keeps Part P electrical safety and certain water requirements in force where services are shared with the house. Gas safety law continues to apply too. This is general information, not advice on a specific project; the local building control body can confirm what applies.

Sources

This guide draws on the following primary sources, current as of 21 September 2026:

• legislation.gov.uk, “The Building Regulations 2010, Schedule 2: Exempt buildings and work”
• legislation.gov.uk, “The Building Regulations 2010, regulation 9: Exempt buildings and work”
• Ministry of Housing, Communities & Local Government via GOV.UK, “Approved Document P: Electrical safety – Dwellings, 2013 edition” (PDF)
• Welsh Government, “Approved Document J: Combustion appliances and fuel storage systems, 2010 edition incorporating 2010 and 2024 amendments” (PDF)

Related guides

Compare Conservatories is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not legal or planning advice on any specific property — always confirm requirements directly with your local planning authority.