Side return extensions: the ultimate guide

Essential advice on adding a side return extension to your home, including tips on how to keep costs down

By Caroline Rodrigues | 17 March 2021

Too narrow for a proper garden, too overshadowed for a patio, a side return might be better used for extra living space. This is especially useful for a house with a deep, thin layout. ‘Not only can side return extensions create full-width space, but there are also opportunities to reconfigure the layout of the house, to flip rooms around, change the circulation or add a utility, WC or dining area,’ says Alex Raher, director of Delve Architects.

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George & James Architects’ split-level kitchen in a Georgian house

Do side return extensions need planning permission?

In many instances, this type of extension may not require planning permission. ‘Under permitted development [PD] you can extend 6m from the rear of a terraced house, or 8m for a detached house. This is from the rear wall of the main part of the house. Not the back of the outrigger – the original portion of the house that extends at the rear,’ says Alex.

‘Under permitted development you can extend 6m from the rear of a terraced house, or 8m for a detached house’

This would allow for the side-return extension of a typical Victorian terraced house. ‘To comply with PD rules, if you’re closer than 2m from the neighbour’s boundary, the eaves will need to be under 3m to gain permission. The maximum height of the extension needs to be less than 4m to comply,’ he explains. You’ll also need a party wall agreement with your neighbours.

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The extension runs along the wall between the garden and street.

 Is there a way to extend further?

If you can push out at the back as well as the side of the house, you’ll gain even more space. ‘A stepped extension, coming out 6m from the original rear wall of the house, to include the side infill and rear extension, can be done under PD,’ says Alex. But a full wraparound extension requires planning permission. ‘It is worth speaking to the local council before submitting as some have policies against wraparounds,’ he says.