Extensions - The Design Process

The design process generally consists of four stages:

  • Planning Application
  • Building Regulation Application
  • Tender
  • Construction

We can assist in any one or all stages, as required. Some extensions do not require planning permission as they can be built under Permitted Development rights, but all extensions require Building Regulation approval.

If you do not have a builder lined up, we can help tender your extension with a select panel of builders, all who have done work with us before.
Generally three competitive quotes are obtained.

Whether or not you have your own builder, site supervision is an important part of the final construction stage. Site visits can be made on a weekly basis to ensure the work progresses smoothly and in accordance with the drawings.

Party Wall Act

The Party Wall act has been in force since 1996 and provides a framework for preventing or resolving disputes where building works affect a party wall, boundary or adjacent building.
If all affected neighbours have no objection to your extension, then no Party Wall Agreement may be needed. To be safe, a standard notice can be given to, and signed by the affected neighbours giving you rights to build your extension, hopefully with no further involvement of the Party Wall Act.
If any neighbour objects, then a full Party Wall Agreement may be required. You, as the commissioning owner, then have to pay for a Party Wall Surveyor to represent the affected neighbours and draw up a Party Wall Agreement. This can be costly and take several months in the worst cases!
See the Fees section for more details on costs.

Planning Application
The design work starts with a survey of your house and the drawing up of the existing plans, together with a discussion on what you require from your proposed extension.
Several options may be drawn up and discussed until a final scheme is approved and signed off. The planning application is then made and a decision is usually given 8 weeks after the application has been registered.

Building Regulation Application
Once the planning application has been made the building regulation application can be made. This concerns the technical details of the construction of the extension, such as foundations, insulation, means of escape, and any structural elements such as beams. A decision is usually given 5 weeks after the application has been registered.
If there are any objections from neighbours to your extension, or if it is large or complex, it may be prudent to wait until planning permission is given before proceeding to the building regulation application.

When building regulation approval has been received, the extension can be put out to competitive tender to a panel of builders who have all completed several extensions with us. Three competitive quotes are usually obtained and a contractor is normally appointed within 3 weeks. Contractors typically quote 4-8 weeks lead time before they can start work.

Most average-sized extensions take 3-4 months to complete. Work is always inspected at key stages by the local authority building inspector, these include foundations, drainage, roof, insulation, ventilation and means of escape.
Weekly site supervision by us is also recommended to ensure the work progresses smoothly and in accordance with the drawings. Progress meetings are also held and minutes distributed to the client and builder.