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Check if you need building regulations approval

Building regulations approval is different from planning permission and you might need both. You need building regulations approval when carrying out building work.

Meeting the requirements of the Building Regulations 2010 is the responsibility of both the person carrying out the building work and the owner of the building.

The Planning Portal has comprehensive guidance on when you may require building regulations approval for your project.

On this page:

What is building work

These are some examples of what constitutes building work:

  • construction of an extension
  • conversion of a loft into a room
  • conversion of a garage into a habitable room, including a store or hobbies room
  • structural alterations to your house, such as the removal or part removal of a load bearing wall
  • installation of cavity insulation
  • installation of new or replacement windows
  • conversion of your house into flats
  • underpinning your house
  • drainage work, including the installation of a sink or toilet
  • building work that affects a public sewer
  • the installation or extension of a service or fitting which is controlled under the regulations.

Your responsibilities

The homeowner has the primary responsibility for submitting your application and achieving compliance with the regulations.

You should also consider that if you are the owner of the building, you may be served with an enforcement notice if the work does not comply with the regulations. It is important that you choose your builder carefully.


To find out if your building project is exempt from building regulations approval, call us on 023 8028 5245 or email We will discuss your project and confirm if an application is required.

Building over or near drains and sewers

If you are planning an extension to your property or would like to construct a new building, you will need to check the location of the public sewers.

Since the Private Sewer Transfer on 1 October 2011, any sewer or lateral drain serving more than one property is the responsibility of the sewage undertaken in your area.

Many household drains are classified sewers under jurisdiction of the water undertaker, and you will need their permission to carry out any work which may affect their drain or the access to maintain it.

Where the proposed new building or extension is to be built within 3 meters of the public sewer as indicated on the public sewer map, a full plans application will be required. Building Control has a duty to consult with the sewage undertaker where this is the case. The sewage undertaker has 15 days to raise any objections.

Public sewers can sometimes be found within the boundaries of properties even though they do not appear on the sewer map. Where these drains serve more than one property, they will be the responsibility of the sewage undertaker and you will require a build over agreement. This may be asked for in the future if you decide to sell your property.

The building control approval and completion certificate is not a substitute for a build over agreement.

Any extension that is built over or close to a sewer or drain shown on the official map of sewers or not as the case maybe, must comply with the requirements of Requirement H4 of Schedule 1 to the Building Regulations.

You can find out whether any sewer or drain affected by your project is on the official map of sewers, by asking the Council. In such cases, we will have to consult the sewerage undertaken, who may stipulate conditions before you can carry out the work.

The Approved Document to Part H4 of the Building Regulations makes it clear extensions should not be constructed over a manhole or inspection chamber or other access fitting on any sewer serving more than one property.

Drains and sewers must be adequately bridged and protected, and foundations extended locally to allow for such pipework to pass through walls where they are less than two metres deep.

In some situations, special foundation arrangements must be made to protect drains and sewers, and the building or extension itself, from the effects of settlement.

Before undertaking any building work close to or over drains and sewers, you should consult your local authority building control team, or alternatively consult the sewer authority who you pay your water bills too.

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