Extending a listed property: can we replace our Sixties-built extension with a larger version?

We live in a Grade II-listed house with a large rear garden and an unsightly Sixties-built extension. Can we replace this extension with a newer and larger one?
Top of the list: to build or alter an extension or conservatory on a listed building you need listed building consent. This extension in Kennington, by Nick Leith-Smith Architecture + Design, proves how innovative you can be
MARCUSLYON.COM
Selwyn Atkinson3 December 2019

Question: We live in a Grade II-listed house that has a large rear garden. We’d like to replace our rather unsightly Sixties-built extension with a larger version because we are desperate for more space and the garden has bags of room.

However, friends tell me that we can’t extend under permitted development rules because the rest of the house is listed.

What is the correct procedure when applying for consent? And what is the likelihood of getting our listed building consent application granted?

What we are planning will be far superior to the extension we have now.

Answer: The Secretary of State for Digital, Culture, Media and Sport may preserve any building — or a group of buildings — that has or have architectural or historical “special interest” by entering it on the designated list.

Once listed, the council will seek to preserve the building, its setting, or any features of special architectural or historic interest within its curtilage.

There are several reasons why a building might be listed, such as the craftsmanship of its architecture and/or the scarcity of similar surviving buildings from the same period.

For example, houses influenced by the Arts and Crafts movement of the late 19th century were built using locally sourced natural materials.

They were built to a very high standard by a handful of local skilled crafts workers who oversaw the project from start to finish.

The Arts and Crafts movement was the antithesis of modern manufacturing and mass production, which led to the substitution of skilled crafts workers by unskilled assembly line workers.

The decline in small-scale manufacturing illustrates an important aspect of history, which is why such buildings with both special architectural and historic interest should be conserved.

The starting point for the assessment of an application for listed-building consent is Section 16(2) of the Planning (Listed Buildings and Conservation Areas) Act 1990.

A review of the list entry using Historic England’s online database should identify whether the recently built Sixties extension makes a positive contribution to or harms the property’s “special interest”.

If the list entry makes no mention of the extension, then you may be able to demolish it and substitute an alternative and larger design, subject of course to going through the full process of a planning application and gaining listed building consent.

But to be sure that this is a genuine possibility, before discussing and commissioning costly designs with either an architect with expertise in working on listed buildings, or with a specialist conservatory company with similar expertise, you should seek advice from the council conservation officer before proceeding to make your application.

In 2015 a planning inspector allowed an appeal against a decision by the local council in Bath to refuse an application for listed building consent.

The inspector considered that removing an “unattractive” lean-to roof would enhance the setting of the Grade II-listed house in question.

The inspector determined that the new glazed conservatory would not in fact detract from the building’s special interest, as it would appear “lightweight” and subservient in scale to the original house.

The glazing would also allow for clear views towards the original façade brickwork.

The replacement extension gave the appellant an additional 10sq m of living space.

In another example, an appeal was allowed permitting the replacement of a Seventies rear extension to a Grade II-listed house.

The inspector noted that the existing “utilitarian” extension related poorly to the main building and that its replacement with a larger extension of an additional 1.5 metres in depth, would not dominate the garden or the original building and would not harm its special interest.

But do be aware that it is a criminal offence to carry out works to a statutory listed building without prior consent from your council, so you have to get permission first.

Selwyn Atkinson MRTPI is planning associate director at GL Hearn, part of Capita PLC. He cannot answer your questions individually but we will try to feature them here.