A loft represents a large proportion of unused space in your home; this week we suggest how good use can be made of this otherwise wasted area.

The majority of houses have space under the roof that usually contains little else than the cold water storage tank and hot water header tank. This space can be as much as 30% of the total floor area of your home and in some cases is totally wasted space that can be converted into useful storage space or even habitable rooms.

If we use the loft at all, many of us only use our loft space for storing little-used items such as Christmas decorations, old papers and pictures. In many cases we don’t touch things from one home move to the next.

But it doesn’t have to be like this; almost any loft can be converted into an easy-to-use storage room and some can be turned into an extra living room.

A simple improvement in use for extra storage space requires only the provision of a suitable sized opening in the ceiling and some type of ladder as a means of access. A habitable room on the other hand will almost certainly require the strengthening of the existing ceiling joists, insulation and lining the underside of the rafters, providing windows for natural light and ventilation and a permanent ladder or staircase for access.

You won’t need planning permission or building regulations approval to install a loft storage space but you will need building regulations and probably planning permission for a habitable room.

Because heat rises, much of the heat in your house goes straight through the roof. Most recently built houses will be fitted with loft insulation, reducing the rate at which heat is lost, conserving energy and your heating bills. Many older houses have also been fitted with loft insulation too. Adding an insulated room to your loft will improve your home's insulation still further.

If you plan to use the loft space for a room rather than just storage, the sloping roof needs to be insulated to keep the heat in. Insulation laid under the roof felt must have a ventilation gap of 50mm behind it. Roof insulation has the effect of making the un-insulated parts of the roof colder than before, so increasing the risk of condensation (from moisture we ourselves introduce into the house via breathing, washing cooking etc). This can be reduced by a vapour barrier, usually foil backed plasterboard, on the inner side of the insulation.

The construction of the ceilings and roof space in your house depends upon its age. Older houses built with traditional pitched roofs have open space below the rafters. Modern roofs usually have roof trusses – prefabricated timer frames incorporating rafters and ceiling joists - which are easier to erect but leave open less space under the roof.

Both types of roof can allow space for storage but roofs with trusses are not easily converted into a habitable room without specialist advice.

Safety – When working in the dusty loft space, wear protective gloves, eye protectors and a face mask. Always use a well-secured ladder for access into the loft. Do not use a stepladder, as this can be unstable particularly when not restrained. You may also require a safety lamp and extension lead unless your loft is already wired for power.

Lay planks over the loft joists so you don’t put your foot through the ceiling of the room below.

Bats may be roosting in your roof and there’s a good chance you won’t know about it either. All bats and their roosts are protected by law and must not be harmed. But this does not necessarily mean you can’t work in your loft. The usual evidence of bats is their droppings. By law you must advise one of the Statutory Nature Conservation Organisations for advice on their protection before you start any work that may disturb them. The Bat Conservation Trust can be contacted on 0845 1300 228 for more information or see www.bats.org.uk

To make use of the loft space you need to be able to access it easily. The easiest way top do this is to install a fitted, extendable, loft ladder, which folds back and is stored out of the way in the loft space.

To install it however, you may need to enlarge your existing hatch or create a completely new opening in a better position.

You will also need to board out some of the loft space to provide a safe surface on which to walk and store items. Storage shelves can be located between the segments of a trussed roof, thus gaining valuable extra space otherwise lost in this type of roof construction.

Loft ladders are made of wood or aluminium and come in either fold-and-slide or concertina type designs. They are made in a variety of lengths to suit heights of 2.3, 2.5, and 2.9-3m measured from floor to top of the loft joists.

The manufacturer will specify the size of hatch opening required and the pivoting height required inside the loft. Take care to measure up in the loft and between the joists before purchasing the ladder.

Ladders are hinged at the hatch and some swing down with a handrail. Some can be operated from inside the loft. Some loft ladders come with a loft hatch door that swings as part of the opening operation.

A sliding ladder is simple to install and operate: it is lowered by means of a pole hooked over a catch on the bottom rung. It has two or three sections, with spring locking catches to hold it in the fully extended or closed position. Some are fitted with a spring, which prevents the ladder from dropping down under its own weight and this also makes it easier to raise the ladder into the roof.

If you need to enlarge your existing hatch you will probably have to cut a way part of a joist. This is part of the roof structure and should not be done without care and consideration. On older houses one joist can usually be safely cut away but on modern post war houses the roof is designed so that every part plays a vital role – any alteration may weaken the structure, so check with your Building Control Officer before proceeding.

If the floor of your loft consists of exposed joists you will need to lay down a safe firm flooring before you can use the space for storage. Tongue-and-groove chipboard conveniently sized to pass through the loft hatch is available especially for loft boarding out. 18mm thick and 1220mm long, they usually cover three joists each.

Before boarding the loft check you have adequate insulation. The minimum recommended depth is 270 mm, but many houses will have less. If so take the opportunity to top it up with a blanket or loose-lay insulation. His will make your heating more efficient and may bring down your bills significantly.

You will need to re-route any electric cables before boarding out but don’t cut any joists with channels as you will weaken the joists. If the cables need to cross over the joists they can do this at the eaves. Get an experienced electrician to do this work for you if you don’t have the relevant experience yourself. While the electrician is there ask him to fit a light and switch for you.

Before laying down the boards check that no wires or pipes will be damaged when drilling or screwing the boards down. You won’t be able to see them after the boards are laid in position.

Don’t forget that if you haven’t put in new or strengthened joists then the boarded out space will not be strong enough to carry heavy weights. Anything heavy should be placed near the eaves where the joists are supported by the walls of the house. Also, when planning the layout of the storage area don’t forget that the ladder takes up space in the loft when retracted.

B&Q have a range of loft ladders, boarding materials and useful tools such a joist detector, trailing safety lamp and dust sheets. Our brief details on how to fit a loft hatch are taken with kind permission from B&Q’s ‘You Can Do It’ step-by-step book of home improvement. Full and detailed instructions of how to fit a loft hatch and board out your loft are in the book, available at all B&Q stores at RRP £16.98.

There are many different uses for a loft conversion and the following are some considered as habitable rooms:

• Studio for painting, writing, study etc.
• Photographic darkroom.
• Office or computer room.
• Games room.
• Extra bedroom.
• Kitchen.
• Extra lounge.
• Recreation room.

A bathroom or shower cubical can also be built in the loft but these are not considered ‘habitable rooms’ under current building regulations.

Before you plan a loft conversion it is advisable to see what already exists in the roof space. It won’t be too long before you will need measurements to make the necessary drawings, so this might be a suitable time to measure up. Take a lamp or torch and climb into the roof space. A good tip would be to take two or three 25mm thick planks to span the ceiling joists and walk on. It could stop you accidentally putting a foot through a ceiling.

Check the overall width and length of your loft, the clear distance between the purlins and other structural roof members, the size and position of the chimney and other obstructions such as the water tank.

While you are in the loft space it is a good opportunity to check for bats, dry rot, wet rot or woodworm as any of these will require specialist advice.

Any dimensions less than about 3 metres will make the living space very small. Don’t forget a stairway will also have to come into this area. The height is also important and you will need a minimum clear height of 1.9 metres over most of the width of the proposed room.

A modern house with a trussed roof (prefabricated 'triangle' structures incorporating the ceiling rafters) will almost certainly make a room difficult to achieve because of the small amount of space available, but this needn’t be impossible. It will be more tricky and expensive though, needing specialist advice as the timbers may need to be rearranged or the roof raised.

Before finalising your plans and submitting an application to your local authority it may be advisable to discuss your plans with your neighbours. Remember your neighbours are as likely to be concerned about any work that might affect them as you are about any work they might do to affect you. The local authority will advise you neighbours about your plans anyway so it’s as well to sort out any problems with them first.

Problem items:

• Overshadowing neighbours windows.
• Views into neighbours property and garden.
• Party wall issues. Any work that involves a shared wall in the loft should be discussed before work is started.
• Covenants. These are restrictions placed on your property by a previous owner (or a landlord if you are renting or have a lease.)

Covenants will be revealed in your property title deeds and are recorded at the Land Regestry.

Make early contact with your planning authority to get their views on the viability of the project and also whether there are any special construction problems that need to be solved.

Most ceiling joists are not strong enough to carry the load required by a new habitable space in a loft conversion and so it will almost certainly be necessary to strengthen the existing joists, or insert new ones to provide a load bearing floor. Any bending of the existing joists will damage the ceiling below.

Steel joists can be used if new timber joists are unable to be fitted because the span is too large or the reduction in headroom is unacceptable.

Fire resistance of 30 minutes will probably be required, as the living accommodation in the loft conversion will be separated from the ground floor by the existing second floor. This will probably entail laying fire protection with the new floor.

All habitable rooms in the loft conversion require natural light and ventilation. This can be by fitting a roof window or by constructing a dormer window capable of being opened. A dormer window will be one of the items requiring planning approval.

Some roof windows such as those supplied by The Loft Shop can be fully installed from inside the loft space, including the tiling or slating to the roof and flashings.

The building regulations are very precise in the case of a loft conversion in a house and your project must conform in respect of minimum dimensions of the opening part of the window for means of escape in case of fire. Also fire alarms and fire resistant doors will be required. Advice from your local authority is best sought at an early stage. For example, a conversion over 50m2 with more than two rooms must have a separate fire resistant staircase as an alternative means of escape.

While at the planning stage don’t forget that plumbing and drainage might be required and also the cold water cistern should be moved behind a partition where there is adequate space for inspection and maintenance.

As with any home extension, if you plan to use the existing central heating system to heat the conversion then get a heating engineer to check the boiler is capable of supplying the extra radiators. You may also have to reposition the header tank in the loft.

The Loft Shop has 26 shops in London, the home counties and in the south of England and also a website www.loftshop.co.uk and will give free advice on all aspects of loft conversion including a database of installation/builders. The company also provides an advisory service on planning, building control, access and construction.