A Guide to Home Extensions: First Steps

By Orange Key Architectural Design

Extending a home is a popular way to add space without having to move. It is said that for every person who self builds there are 15 that add extensions to their homes (often making more economic sense than incurring the costs associated with moving house).

So if you are expecting a baby and need a nursery, would like to convert your garage to house your teenager (and their drum kit), or dream of turning your loft into a master bedroom, we can help you find the perfect design solution.

Almost all properties (whether an existing home or a newly-purchased house) have building or renovation potential and value can be added to any home by renovating, adding an extension, loft conversion or garage conversion.


A lot of clients ask us how much they should spend on an extension. The cost of extending can be offset against the considerable expense of moving house. But you still need to think whether the value of your house will be increased by the amount you spend on an extension.

The trick is to extend and to come out well in the investment stakes. This means you have to put a lot of thought into even the smallest extension and give plenty of consideration to the elements and features that will not only add value, but will also benefit the way you live.

Carefully considered design will help you achieve this. Please remember that it is a false economy to extend (rather than move) if you are then unhappy with your extension. We will be publishing a guide soon to the design options available from extensions to infills, using state of the art materials and glazing.

But first there are some planning issues to be aware of:

Will I need planning permission?

Whether an extension or outbuildings require planning permission depends on the size of the project, and the level of Permitted Development rights afforded the property. Under the Permitted Development Rights system a large number of home extensions can be built without requiring planning permission.

What is permitted development?

Permitted development rights allow for minor improvements to be made such as small extensions, porches and garage conversions without requiring planning permission. There are a number of conditions to be aware of:

– You can extend a detached dwelling by 8m to the rear if the extension is single storey

– There are height restrictions. A single storey extension not being higher than 4m in height to the ridge and the eaves,

– It must be built in the same or similar material to the existing dwelling.

– Extensions must not go forward of the building line of the original dwelling.

– Side extensions must be single storey, maximum height of 4m and a width no more than half of the original building.

– In Designated Areas side extensions require planning permission and all rear extensions must be single storey.

– An extension must not result in more than half the garden being covered.

– You can only do it once and the original building is either as it was on 1st July 1948 or when it was built.

– You should bear in mind that if your house is in a Conservation Area or a National Park, the amount of work one can do under Permitted Development is usually restricted.

Extending a Listed Building

If you are the owner of a listed building and wish to extend your property, the challenge will be, how to increase your living space without compromising the original character of your home.

Here are a few important things to think about:

1. You will need planning permission to extend a listed building, and you must apply for Listed Building Consent too.

2. Employ an architectural designer who has experience with period homes, and one who can deliver an extension that’s suited to your listed property.

3. If you do not wish to liaise with conservation officers and project manage the build yourself, engage an architectural design practice to do this for you.

Next steps

Orange Key architectSo, if you think your house needs more space, light or an injection of character to save yourself the hassle of moving, Orange Key Architectural Design in Hungerford will be happy to give you a FREE consultation to see how you can breathe some new life into your home.

Orange Key have a wealth of experience working on a variety of different projects and cater to all budgets. To book an appointment please contact them on 01488 682918 or [email protected]


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