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What Permissions do I need before I can build an Extension to my Home

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Many people decide to extend their home rather than moving. If you are happy with your home and just need more accommodation, then this is an option that’s well worth considering. However, before you start, you’ll need to establish what formal permissions may be required.

When considering the extension of your home you should certainly consider the following;

Planning Permission

The work may consist of ‘development’ as defined under the Town & Country Planning Acts (as amended). If so, you may need to apply for planning permission. However, many areas in England allow certain ‘permitted development’ rights that waive the need to apply for planning permission for extensions up to a particular size, subject to certain caveats.

How to Submit a Planning Application

Building Regulations

If your works consist of ‘building works’ as defined under Regulation 3 of the building regulations then you are likely to need to meet the design and build criteria set out under the various parts of the building regulations (these are different to planning regulations).

It’s usual to be required to submit structural and/or drawings as part of your application for building regulations. In most cases an inspector will want to visit several times at key stages of a project to ‘sign off’ that the project meets modern regulations. It used to be that a local authority inspector undertook building regulation inspections but nowadays you can also employ your own to do this work and arrange the formalities.

As part of the building regulations, you will need specific certification from properly qualified electricians and heating engineers (see below). At completion you will be issued with a certificate, which you should keep safe as you may need it when selling your home.

You will probably need to apply for building regulations when you propose to;

  1. Put up a new building
  2. Extend or alter an existing one
  3. Provide services and/or fittings in a building such as washing and sanitary facilities, hot water cylinders, foul water and rainwater drainage, replacement windows, and fuel burning appliances of any type.

There are certain exemptions available for certain building types.

Gas Certificate

A building regulations compliance certificate will be issued by a registered gas safety engineer whenever a new gas boiler or hot water system is installed by them. To obtain a list of registered engineers certified to do this work go to the Gas Safe Register.

Elecrtical Certificate

You will almost certainly require Part P certification for any new electrical installations.

Part P compliance is required when;

  1. installing a new new circuit, whether at low voltage (typically 230 V) or extra-low voltage) or
  2. replacing a consumer unit (fusebox) or
  3. altering or adding to an existing circuit in a ‘special location’, whether at low voltage (typically 230 V) or extra-low voltage. For example, a bathroom.

Energy Performance Certificate

The regulations around Energy Performance Certificates (EPCs) now require that all new property must have an EPC once completed. It is the owner’s responsibility under Building Regulations to apply for a new EPC. It’s worth noting that the extension of a home to facilitate a glazed conservatory, for example, might dramatically change the energy efficiency of the entire building. You may be required to improve the energy efficiency of the existing building in order to offset this reduction.

See our blog: What is an Energy Performance Certificate (EPC)?

Landlords Consent

If you are a tenant, you may well require formal ‘landlord’s consent’ from your landlord before undertaking some building works. It is prudent to check your lease.

Title and Contractual Restrictions

Even if you own your Freehold, you may be restricted over what is allowed in terms of development. ‘Development’ may well include a proposed change of use or the extension of a property.

Rights of Light

You should check that any extension does not significantly reduce the amount of natural light available to a neighbour. If unsure, consider taking advice from a chartered surveyor that specialises in ‘rights of light’ issues.

In England, most homeowners have the right to permitted development rights.

Important Note

Whilst this article provides an overview of the permissions what you may require before you can build an extension to your home, it is certainly worth speaking with your local planning authority prior to committing to work, as circumstances may differ locally (for example, the removal of permitted development rights, etc).

If unsure, consider applying to the local planning authority (your District or Borough Council) for a Certificate of Lawful Development. An application usually costs £75. This will not cover other issues such as the need for building regulations. For more information on permitted development visit

As ever, we recommend that specific professional advice is sought on a case-by-case basis. Scotland, Wales and Northern Ireland each benefit from a variance on these rules, so it’s always prudent to check with the relevant planning authority.

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