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Home Extensions
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Home Extensions - Bungalow Conversion to a House - Front
Bungalow Conversion to a House - Front
Home Extensions - Bungalow Conversion to a House - Rear
Bungalow Conversion to a House - Rear

Home Extensions can provide extra bedrooms, an office, a playroom for your children, a larger kitchen or just a conservatory to relax in.

And extending your home is an excellent way to gain more living space without the hassle and costs of moving.

Depending on the design of your home you could consider a side extension, double or single storey rear extension, loft conversion or garage conversion.

But before deciding dip your toes into the world of home extensions, you should give careful consideration to the following:

Planning Permission and Building Regulations

The cost of home extensions

Designing home extensions

Building home extensions

Heating, electrics and plumbing


Planning Permission and Building Regulations for Home Extensions

Is Planning Permission required for Home Extensions?

Not always. In many cases home extensions can be built under Permitted Development rights as long as you meet the required criteria. If your home extension does not meet permitted Development rights criteria, it will require planning permission.

Permitted Development rules as they apply to houses are as follows:

  • No more than half of the area of land around the ‘original house’ can be covered by extensions
  • No extension can be built nearer to a public highway than any part of the ‘original house’
  • No extension can be higher than any part of the ‘original house’
  • Single storey extensions must not extend more than 8 metres beyond the rear of the ‘original house’ for detached houses and 6 metres for other properties. For extensions of more than one storey the limit is 3 metres.
  • Maximum height of a single storey extension must not exceed 4 metres.
  • Maximum eaves height of 3 metres within 2 metres of a boundary
  • Side extensions to be single storey with maximum height of four metres and width no more than half that of the original house.
  • Two-storey extensions no closer than seven metres to rear boundary.
  • Roof pitch of extensions higher than one storey to match existing house.
  • Materials to be similar in appearance to the existing house.
  • No verandas, balconies or raised platforms.
  • Upper-floor, side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor.

‘Original house’ means as it was originally built or on 1st July 1948 if built prior to that date.

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Building Regulations for Home Extensions

You don’t normally require Building Regulations approval for a single-storey building less than 30m2, or any building less than 15m2, as long as there’s no sleeping accommodation.

Neither do you need Building Regulations approval for a conservatory or orangery with an internal floor area of less than 30m2.

For all other home extensions you will need Building Regulations approval.

The Cost of Home Extensions

A single storey home extension should cost between £1,000 and £2,000 per square metre and a double storey extension around 25% more.

The factors which affect the cost are:

  • Location in the country
  • Size of the home extension (large extensions normally cost less per square metre)
  • Specification and complexity of your home extension
Designing Home Extensions

When designing home extensions, there are 3 basic options,design it yourself, employ an architect or use a design and build company.

Often, in practice it will be a a combination of all three as you will have an idea of what you want, an architect can draw it up with his or her interpretation and amendments and a building company will see it to fruition, often with more amendments.

Either way you will need your plans drawing up to submit a planning application, to apply for Building Regulations approval and for a building company to use as basis for drawing up a quotation.

Building Home Extensions

Traditionally the architect who was responsible for drawing up your home extension plans would also act as a project manager for a percentage of the total cost. The project manager would specify products and find the various trades people to complete the work.

More often though, design and build companies will take responsibility for all aspects of the project. They would normally employ people with the main trades required and subcontract to others such as plumbers and electricians.

Having one company take responsibility for everything can be a good idea to avoid clashes between workers when something goes wrong – as it does on  most home extensions. Problems can happen with any home extension, it’s how the company deals with it that they should be judged on.

Heating, Electrics and Plumbing for Home Extensions


Your existing central heating system needs to be assessed as to whether it would cope with heating your home extension as well as the rest of your home.

You need to decide whether you need to install a larger capacity boiler or install a separate heating system altogether for the extension.


If you are adding a kitchen to your house you are likely to have to add a circuit that goes directly from the distribution board. For any other work, unless it is very extensive, it is usually possible to extend the existing ring circuit.

An extension will give you the opportunity to add to your existing power points. Many people in this position take the opportunity to replace single socket outlets with double ones and install outside lighting.


This will depend whether you are adding a kitchen, bathroom or en-suite as part of your home extension. The architects working drawing should specify where the various facilities are located and where pipework is connected.