Conservatories, garden rooms and orangeries come in many guises. Are you bewildered in this New Age glass era?

When considering a development, or sale, it is important to the value of your house that you get it right, both on the ground and with the planners so that future estate agents' valuations are not a disappointment to you.

On my visits to properties, what I perceive as the use of a room tacked onto the back of the house is never the same as the vendor! I can find myself cringing when I am corrected by the home owner, which I find is now happening ever more frequently.

More and more properties seem to have a glazed appendage on one elevation or the other.

Now don't let me give you the impression that I am against the principle of additional space, but I do feel that to obtain the best value for money and create the right appearance, some degree of thought needs to be given before embarking on what is often an expensive project.

More recently the number of manufacturers supplying "conservatories" (I use this as a generic term) has greatly increased, in practice they can be all things to all men.

To put the record straight, the definition of a conservatory is "having the quality of preserving from loss or decay; or a greenhouse for exotics attached to a dwelling".

A garden room is "additional accommodation within the curtilage of a dwelling".

The definition of orangery is "a place for raising oranges; a plantation of orange trees" - not a lot of oranges to be seen growing in the Midlands.

Invariably, many conservatories are particularly cold in the winter due to lack of insulation or lack of heating and too hot in the summer. In this country the use of internal roof fans in the summer is as yet only marginally fashionable.

From an estate agent's perspective it is only when the "conservatory" develops to a "garden room" with solid walls, full central heating, a slate or tiled roof, do we start to see any appreciable increase in value.

There are some companies producing excellent garden rooms, many with smoked glass, hardwood internal floors and roof timbering.

These in themselves can add substantially to the value of the property, but as with anything to do with property, location is all important.

Sitting in your very expensive oak-framed garden room with Farrow & Ball decorations, but looking at your neighbour's brick wall, will not create the desired ambience for many prospective purchasers.

One of the reasons for the extensive use of PVC is on the grounds of cost, but there are various other factors that come into play, namely simplicity and ease of construction and whether or not consent can be obtained from the local authority.

This is where we enter into a mini-minefield, but in broad-brush terms, you need to consider whether the property is in a conservation area, the structure is in front of the building line, and if the construction has solid walls, roof etc.

Accordingly, you may have to apply for planning consent and building regulations. Conversely, if the structure has translucent walls, roof etc, is not in a conservation area and is behind the building line, then you may not require planning consent (I emphasise "may").

Many properties often stand out as being perfect to warrant this additional living space; then again, there are others to which it adds little or no value.

The important point to remember is that any such additional space should be family friendly and usable.

My personal criteria is that if you feel comfortable sitting reading the paper on a winter's morning in February dressed in shirt sleeves, then it is worth considering.

Finally if you are about to put your property on the market and it has a conservatory, do not use it as a store room for discarded household goods, make it feel like a usable living space - even grow oranges - but in a way that is aesthetically pleasing and complimentary to the main house.