Do I Need Planning Permission for a Rear Extension?

If your home is not in a conservation area or restricted by Listed Building consent, you may find your rear extension falls under Permitted Development.

This means that you can extend up to 8m from the original rear wall of your property on a detached home, or up to 6m on a semi detached or terraced home. In either case, your extension must not be higher than 4m. There are further restrictions if your project is to sit within 2m of a boundary (in this case the eaves must not be higher than 3m).

These measurements apply to single-storey extensions only, but some two-storey additions are allowed too.

Use our Extension Cost Calculator

Choosing a Design Style

If you are carrying out your work under Permitted Development, you will be expected to build in the same material as the existing dwelling. This must be done carefully, perhaps requiring you to source reclaimed materials to get a good match, or tint the bricks for a seamless look.

Alternatively, you could design an addition in a contrasting style. This makes a statement and can be easier to achieve success with than trying to match old and new.

Here, we take a look at some of the finest examples of rear extensions in recent times.

A Striking Clad Extension

This grey rendered blockwork ground floor extension supports a timber frame bedroom ‘box’ above.

A grey rendered blockwork ground floor extension supports the timber frame bedroom ‘box’ above

A Sensitive Extension

A contemporary-style addition clad in western red cedar contrasts with this original Grade II-listed cottage.

A contemporary-style extension clad in western red cedar contrasts with the original Grade II-listed cottage

An Extended and Renovated Cottage

A new glazed space to a traditional whitehouse croft, provides a kitchen and utility room filled with natural light.

A new glazed extension to a traditional whitehouse croft, provides a kitchen and utility space filled with natural light

A Modernist Addition

A cantilevered timber-clad roof appears to float on clerestory windows set above a white rendered wall on one side, and sliding doors on the other.

A cantilevered timber-clad roof appears to float on clerestory windows set above a white rendered wall on one side, and sliding doors on the other

A Listed Stone Cottage Extension

The sympathetic oak frame addition, with reclaimed triple Roman clay tile roof, offers a family sunroom.

The sympathetic oak frame extension, with reclaimed triple Roman clay tile roof, offers a family sunroom

An Extended Farmhouse

Two new structures, clad in timber and Cor-ten steel, are linked to this old farm building with a glazed corridor.

Two extensions, clad in timber and Cor-ten steel, are linked to the old farm building with a glazed corridor

An Extended 1950s Home

This large rear addition incorporates a spacious kitchen diner and separate open plan living room, which open on to a patio.

A large rear extension incorporates a spacious kitchen-diner and separate open-plan living room, which open on to a patio

A Glazed Kitchen Extension

This single-storey kitchen extension opens onto the garden with powder-coated bifold doors from Origin.

single-storey kitchen extension

A Zinc-Clad Rear Extension

This rear single-storey addition to a London flat in a conservation area has been clad in a pre-coloured dark zinc.

Zinc-clad single storey extension

A Frameless Glass Extension

Using contemporary frameless glass, a new bright open plan kitchen/dining/living space has created, which opens on to the rear garden without impacting on the traditional brick shell of the building.

A frameless galss extension on a Victorian house

A Dramatic Remodel

This 1930s dormer bungalow has been transformed into a stunning chalet-style home thanks to a series of rear and side additions.

A remodelled 1930s bungalow

Our Sponsors