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What do I need to know about new foundations for an extension?

Foundations are required to carry and distribute the load of the building safely. Therefore, all buildings should have adequate foundations. The factors that need to be considered when designing a foundation are:

  • Type of soil
  • Adjacent structures
  • Trees
  • Drains and sewers
  • Size and construction of the new building
  • Ground condition
  • Landfill sites

It is advisable to contact a structural engineer or speak to a building control body about plans for new foundations. 

Read more about foundations for extensions

Common Questions

Do I need planning permission to operate a business from my garage?

In most cases, yes - planning permission is required to operate a business from your garage. This is because the use would no longer be purely domestic, and the garage would be considered to have changed use from residential (Class C3) to a business-related use, which requires planning consent.

Do I need planning permission to render my house?

Rendering or cladding the exterior walls of your house may fall under permitted development rights, meaning an application for planning permission is not required provided you meet certain limits and requirements set out in legislation.

If you live in a listed building, you will need listed building consent for any significant works whether internal or external.

If you live in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty or the Broads, you will need to apply for planning permission before cladding the outside of your house with stone, artificial stone, pebble dash, render, timber, plastic or tiles.

Outside these areas, cladding may be carried out without having to first apply for planning permission provided the materials are of a similar appearance to those used in the construction of the house.

If the new materials will not have a similar appearance to those previously used you will be required to submit an application for planning permission.

Read more about change to external walls on our common project.

What is prior approval?

Certain types of development are granted planning permission by national legislation without the need to submit a planning application. This is known as 'permitted development'. In order to be eligible for these permitted development rights, each 'class' specified in the legislation has associated limitations and conditions that proposals must comply with.

One such condition on certain classes of permitted development is the need to submit an application to the local planning authority for its 'prior approval; or to determine if it’s 'prior approval' will be required.

This allows the local planning authority to consider the proposals, their likely impacts in regard to certain specific factors (e.g. transport and highways) and how these may be mitigated.

For more information on prior approval, read guidance on prior approval consent types.

Do I need building regulations approval to install a new inside toilet?

Work to refit a bathroom with new units and fittings does not generally require building regulations approval, although drainage or electrical works that form part of the refit may require approval under the building regulations.

If a bathroom is to be provided in a room where there wasn't one before, building regulations approval is likely to be required to ensure that the room will have adequate ventilation and drainage, and meet requirements with respect to structural stability, electrical and fire safety.

Do I need planning permission or building control approval to install a new external door into my house?

The addition of a new external doorway will often fall under permitted development rights, meaning an application for planning permission is not required. This applies where the new doors are of similar appearance to those used elsewhere on the original building.

Permission may be required if your property is listed, you live in a conservation area oran Article 4 direction is in place. In these circumstances it is best to contact your local planning authority for more advice.

New external doorways which create a new or widened opening must comply with building regulations. A new structural opening will require a building regulations application.

The installation of a new door can be completed by a 'competent person' to ensure building regulation requirements are met. For more information on the competent person scheme and to find a registered person, visit the GOV.uk website.

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