Home extensions and renovations Conservatories: designing and planning

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This article, Home extensions and renovations, was last updated on 10 July 2008 and is now out of date and held in our online archive for reference. Explore our latest Home & garden articles.

 You need to decide whether you want a full conservatory or a sunroom. Your choice will affect the cost, whether you need planning permission and what building regulations apply. 

According to Fensa, the window industry regulator, the definition of a conservatory is:

  • Not less than 75% of the roof area is made from translucent material.
  • Not less than 50% of the wall area is made from translucent material.
  • It is either unheated or heated by a system with its own and separate heating controls.
  • It must be separated from the main residence by ‘external’ doors.
Some people prefer sunrooms to conservatories

Some people prefer sunrooms to conservatories

A sunroom that is added onto the current structure and, for example, has a roof that is not glass, will not meet the definition above and is likely to be classed as a single-storey extension.

Some people choose a sunroom rather than a conservatory as they feel it is more in keeping with the home, and don’t want doors separating the space from the rest of the property.

For more up to date information about how much a conservatory will cost visit Which? Local, or you can ask a question and join the conversation in our Which? Local forum - see the panel on the top-right of this page for the latest threads.

Choose a conservatory that matches your property

Choose a conservatory that matches your property

Key questions to ask when choosing a conservatory

What type of conservatory would you like?

Gable conservatory - a conservatory style that has a steep pitched roof giving lots of light and additional height to a conservatory.

Lantern conservatory - a period style that has two tiers with additional ceiling height in the form of a large ‘lantern’ shape.

What shape and size do you want? 

Conservatories are often thought of as just rectangular or square, but they can also be a ‘T’ or ‘P’ shape. The size depends on what you want to use the conservatory for. If it is a dining room and you want to be able to entertain six to eight people, you should be considering a room measuring 4m x 3m.

What type of frame do you need? 

There are several types of conservatory frame and some bespoke companies may offer you a mixture, such as aluminium on the outside, but wood on the inside, giving you less maintenance hassle.

What kind of roof do you want, glass or plastic? 

If you choose plastic, polycarbonate sheeting is the most common type. Make sure that any glass used is toughened and ideally is capable of reducing the amount of heat going in and out. Try to ensure there is a 25-degree slope on the roof as this will allow it to stay clean more easily than a shallower pitch.

What sort of lighting will you need? 

If you want to use the room in the evenings, it’s worth choosing soft lighting, such as spotlights, table lamps, and uplighters or downlighters.

Choosing the glass for your conservatory

It is essential to get good-quality windows, as this will ensure you can use your conservatory all year round and save on heating or cooling costs.

The glass should be double-glazed, specialist safety glass and be able to keep the heat in without ‘over heating’ the conservatory (such as Pilkington K Glass or Reflex Glass). Ensure that it is laminated glass for security and to reduce the strength of the sun’s rays.

Make sure that your conservatory is well secured with high standard locks and panes that can’t be taken out of their frame.

Inspiration for your conservatory

There is lots of help available when choosing a conservatory design, both online and in the many showrooms available. Visit www.conservatoryselect.co.uk and www.ultraframe-conservatories.co.uk. This last one allows you to upload a picture of your own home and then ‘drop’ in a conservatory style and see what it looks like.

More on this...

  • Looking to put in new windows along with a conservatory? Visit our guide on how to buy double g lazing
  • Thinking of going upgrading your loft instead? See our advice on converting a loft
  • Problem with a builder or decorator? Find out how to deal with dodgy builders and decorators