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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

How can I find out if my land is in a green belt?

The green belt is a specially designated area of countryside protected from most forms of development. It is protected to help stop urban sprawl, preserve the character of existing settlements and encourage development within existing built-up areas.

The government are working on improving access to public land records, allowing you to check certain restrictions on land. You can view their progress here and see whether your land is greenbelt (note: this tool is currently under development).

You should contact your local planning authority to find out if your land is in a green belt area, and any policies or restrictions that may apply as a result.

Where can I find information about change of use class from C3 to C2?

An application for full planning permission for a change of use is often required when changing from a house (use class C3) to a residential institution (use class C2). This is due to the increased activity which a C2 use would have on the local street area through the addition of visitors, staff and changes to parking.

Read additional information on use classes and changes of use.

Can I change my house into a shared house for students (HMO)?

In many cases, yes. Converting a single residential property (Class C3) into a small House in Multiple Occupation (HMO) for up to six occupants can often be done under permitted development rights, specifically under Class L. This means that planning permission isn’t usually required.

However, if your property is located in an area covered by an Article 4 Direction, permitted development rights are removed, and you would need to apply for full planning permission to change the use from C3 (dwellinghouse) to C4 (HMO).  

Read more information about use class changes on Planning Portal

What is a party wall?

A wall is a 'party wall' if it stands astride the boundary of land belonging to two (or more) different owners, for example the wall separating two semi-detached properties.

Some kinds of work carried out to a property may not be controlled by the building regulations, but may be work which is covered by the Party Wall etc. Act 1996. This is a separate piece of legislation with different requirements to the building regulations.

To find out more about party walls, visit Planning Portal.

Do I need planning permission to convert flats back into a house?

Deconversion is the process of restoring a previously subdivided house back to its original state as a single property. Merging flats to create a single house may require planning permission, so you should discuss proposals with your local planning authority before starting work.

Read more about converting flats back to a house.

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