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Elite Edition

Is it easy to get planning permission for an extension?

Author

Sarah Martinez

Published Apr 06, 2026

Is it easy to get planning permission for an extension?

Every kind of extension – one or two storeys; front, side or back; an addition to the roof, a porch or a conservatory – technically requires planning permission. Many already have it thanks to the General Permitted Development (PD) Order, subject to a minefield of criteria and provisos.

How much does it cost for an architect to draw up plans for an extension?

Most architects will charge by a percentage of the total cost of the building works. This ranges between 5 – 12% on average. Architect fees for larger, more complex house extensions are usually charged at 10% of the final cost.

How much does an architect cost for a house extension?

When do you need planning permission for an extension?

If the extension is more than half the area of land around the original house, you will need planning permission. If you go for building regulations approval, it is advised to notify your local authority and apply for a Certificate of Lawful Development to ensure you have the proof that development fell within these rights.

Where can I apply for an extension to my house?

Read about how your extension may affect your neighbours. A householder can apply online to the local planning authority when they intend to build a larger single-storey rear extension, as described above.

How tall does a house have to be to get planning permission?

This requires that the relevant Local Planning Authority is informed of the proposed work via a prior approval application. Maximum height of a single-storey rear extension of four metres. Extensions of more than one storey must not extend beyond the rear wall of the original house* by more than three metres.

Do you need prior approval to build an extension?

The scheme relates to planning and is a method of prior approval; if you wish to build a large extension you must notify the local authority, who will then consult the adjoining neighbours to advise them of your planned development.

What to do if you want to build an extension without planning permission?

So if there’s only one piece of advice to give, that is to get design professionals involved to ensure that your proposed extension can be considered exempted/permitted development. Then obtain confirmation from your local authority’s planning department.

How can I find out if my neighbour has planning permission?

Search the register of planning decisions. Plans for all new developments that need planning permission are made public by the council. This could be an extension to your neighbour’s property or a new school in your area.

What do I need to apply for planning permission?

If you are about to submit an application for Planning permission then you need to complete a risk assessment on the likely reactions from your neighbours.

Where can I find the Register of planning decisions?

Home Housing and local services Planning permission and building regulations Search the register of planning decisions Plans for all new developments that need planning permission are made public by the council. This could be an extension to your neighbour’s property or a new school in your area.