HTF Guidance Note 2 – March 2011, updated Aug 2024
Work that is controlled under The Building Regulations
This guide outlines the types of domestic building work that fall under the scope of the Building Regulations. In short, it covers work to a house or flat that legally requires the submission of a building regulations application before the work begins. You can find separate guidance on how to apply on our website. Below, we’ve grouped the types of controlled work into categories and provided more detailed information on each.:
- Erecting and/or extending a building
- Changes of use from or to a dwelling
- Alterations that will ‘materially affect’ compliance with certain regulations
- Work to controlled services
- Renovation of thermal elements
Erecting or Extending a Dwelling
Most people will know that it is necessary to seek Building Regulations permission in addition to planning permission if you plan to build a new house or block of flats. Subsequent extensions to such buildings are also usually controlled, although certain types, such as porches, conservatories and covered ways/carports, may be exempt from control. You can find further guidance on these exempt categories of extension in our guidance notes titled Exempt Building Work.
Changes of Use
Changes of use to any building to create houses or flats is controlled work as is work where a building contains a greater or lesser number of individual dwellings.
If you plan to change the use of only part of a building from a non-habitable to a habitable use, then that’s also controlled work requiring that you make an application. That might be a garage conversion or a loft conversion and rules apply to ensure that they are safe, healthy and energy efficient.
Alternatively, it may be that you are proposing to change the use of an existing dwelling to another purpose. Some such changes are controlled including to a hotel or boarding house or a shop. Taking in lodgers or sharing a dwelling with non-family members isn’t controlled if people are living together as a single household, ie with all occupants sharing the facilities. There is a limit of 6 persons in such an arrangement after which it becomes a controlled change of use.
You can also set up a small office, surgery or consulting room in a house to be used by an occupant in a professional or business capacity and this would not be classed as a change of use.
‘Material’ Alterations
There are many alterations that you can carry out to your home without needing to make an application under Building Regulations. Those that do, generally fit into 3 categories;
Structural Alterations – affecting the structural elements such as foundations, loadbearing walls, floors or roofs. Works in this category include underpinning, new door and window openings, removing loadbearing walls (‘knock-throughs’) and removing chimney breasts. Adding solar panels to a roof is also controlled as is replacing a roof covering with a heavier or lighter material
Alterations that may affect fire safety – Such as removing or replacing fire doors or layout changes that affect the protected routes of escape from a house in a fire. Alterations to a smoke detection/alarm system would also be covered.
Alterations that adversely affect the accessibility of the dwelling to people with disabilities – The removal or alteration to a wheelchair accessible entrance or to a ground floor accessible WC to a house are examples.
Some alterations fall under Building Regulations because they change a structure that was previously exempt from control. For example, if a conservatory or porch – originally exempt has its separation from the main house removed, or if a translucent roof is replaced with a solid one, it may no longer meet the exemption criteria. Similarly, converting a detached outbuilding into sleeping accommodation brings it under Building Regulations. For more details, see our guidance notes titled Exempt Building Work.
Work to Controlled Services and Fittings
These are services and associated fittings such as electrical and drainage (sewage, wastewater and rainwater disposal) systems, fixed hot water and heating systems and fixed cooling systems. Windows and doors between heated and unheated spaces are also a type of controlled fitting. Examples of controlled work in this category:
Replacement Windows – note you don’t have to make an application if your installer is registered with one of the government-approved competent persons schemes (CPS) such as FENSA
New or Replacement Heating or Cooling Appliances – includes boilers, solid fuel stoves and fixed air conditioning units. These systems are subject to regulations that cover safety, energy efficiency, and carbon emissions. There are also competent persons schemes covering this type of work. Key schemes include NAPIT, BESCA, and APHC. For more details, see our guidance notes titled Competent Person Schemes.
New or Replacement Central Heating – The regulations look for these to meet current standards of energy efficiency.
Installation of New and Replacement Bathrooms, Kitchens and Utility Rooms – The associated drainage alterations are controlled but not if there is negligible change to the existing drainage pipe layouts.
Electrical Works – Electrical installations are regulated under Part P of the Building Regulations. All work should be carried out, inspected, and tested by a competent electrician. If you’re not using an installer registered with a Competent Person Scheme (CPS), you must submit a building control application for certain types of work such as replacing a consumer unit or installing a new circuit. Electrical work in special locations, including bathrooms, areas with showers, swimming pools, or sauna heaters, is also notifiable and strictly regulated.
Renovation of Thermal Elements
This category of controlled work includes repairs, refurbishments, and upgrades to roofs, ground floors, and external walls – whether through the replacement of existing layers or the addition of new ones. These works offer a valuable opportunity to improve the thermal performance of your property, helping to conserve energy and reduce carbon emissions.
Major renovations are controlled where more than 25% of the thermal envelope of the building are renovated or more than 50% of an individual element. Typical examples of this type of work would be:
- Replacing the waterproof membrane on a flat roof
- Re tiling a pitched roof
- Rendering or cladding an external wall
- Internal replastering or dry lining of an external wall
The regulations and Approved Document L set targets for improved thermal performance depending on the existing performance. If an upgrade would not be viable for technical, economical or functional reasons then we would not insist on you meeting those targets.
Further Advice and Information
This guide does not cover every aspect of controlled building work and should not be considered comprehensive. If you’re planning domestic work on your Hertfordshire property and need tailored advice, our team is here to help – please don’t hesitate to get in touch.
Get in touch to see how we can help:
📞 01438 879990
📧 building.control@hertfordshirebc.co.uk
