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Image of an extended house.

Many properties provide potential for expansion - either up, out or even down. Providing building works are undertaken sensibly, such work can add value to your home while giving your family more room to live and work. With a little imagination and some expert advice, you could add a conservatory, convert your loft space into the home office or spare room you've always wanted, or even excavate a cellar or basement. Its also useful for those looking to improve their property before putting it on the market, or for homebuyers planning to take on a property with a view to developing it.

An extension to your home is a major project. It will probably cost thousands of pounds and may cause considerable disruption while works are being carried out, but if carefully planned and executed your extension should add value to your property and greatly enhance your living space. To minimise the possibility of running into problems, consider appointing a chartered surveyor to take you through the process from start to finish and ensure that works are carried out with as few hitches as possible.

When moving house a chartered surveyor can advise you on which properties have potential for expansion or improvement. A chartered surveyor can act as your agent when dealing with the statutory authorities; they understand planning law and compliance with the Building Regulations and have experience of historic and listed buildings. Chartered surveyors have experience in seeking and appointing reliable building contractors and can act as project manager, managing the contract and monitoring the work on your behalf. A chartered surveyor can produce initial designs and then plans and specifications for your builder to work to. They can also provide a cost consultancy service - managing your budget throughout the project to ensure you do not overspend. If your project runs into problems, chartered surveyors can also offer advice on the best method of settling any dispute that may arise.

- The size and shape of your house and garden.
- How much additional space you want or need.
- How much you can afford.
- Whether the project will add value to your property.

If you live in a conservation area, Green belt or your home is listed there may be additional constraints on the type of works, if any,  that you can undertake. If you are unable to extend your home beyond its existing boundaries it may still be possible to knock down an internal wall to create more space or even partition a room to add a bathroom or study area. Planning permission is not normally needed for internal alterations, or for minor extensions or additional buildings within the boundary of your property. However, there may be additional restrictions on permitted development rights especially in conservation areas. The first thing you should do is informally discuss your ideas with your local planning officer to see if permission is likely to be granted. Don't just presume that if the neighbours have a loft conversion or other development that you'll be granted permission too - regulations may have changed over time. As a general rule, in a terraced house, if your extension is more than 10% of the external volume of your home or 15% in a semidetached or detached house, planning permission will be required. In Scotland, planning permission is required if the extension is more than 20% of the external volume of your home or 10% for listed buildings or those in conservation areas.

If you are refused planning permission there is a right of appeal but if you go ahead with a building project without permission, you could be served an 'enforcement notice' which could mean you are forced to demolish the work you have just done.

Your extension project may not only need planning permission but also building regulations approval. This is to ensure amongst other things that your home remains structurally safe, protected from fire risks, is energy efficient and has adequate ventilation. This is a complex area that has your health and safety at heart so if you have any doubts on how the regulations may affect you then don't leave it too late - consult a chartered surveyor before you sign-off the design and appoint a builder. The rules that govern building regulations can be viewed at the Planning Portal website.

Once work has started, a building control surveyor will make a number of checks to ensure that the building regulations are complied with. It is important that you obtain a Completion Certificate at the completion of the works. If this is not provided it could prove a problem if you ever wish to sell the property. All applications are different and the rules are complex so it is well worth considering employing a chartered surveyor to draw up and submit the plans, obtain approvals and oversee the project on your behalf.

If you don't have the space to extend your house upwards or outwards you could always consider going down. Cellar conversions are becoming increasingly popular for creating fun or practical space - e.g. home cinema, games room, utility room, storage area. However, they should always be carried out by skilled professionals, particularly if additional excavation is required. The advantage is that you could add an extra storey with little change to the external appearance of your home. However, cellar projects can be complex and may cost up to three times more than a loft conversion. Check with your local planning officer before starting excavation works. So always look at other options before considering this type of alteration.

If you need more space but don't want to lose part of your garden, expanding upwards could be the answer. More than a million homes in the UK now have loft conversions, with the market growing by an estimated 10% each year. Estate agents calculate that an average loft conversion costs around a third of the price of moving to a property with an extra room. And turning your attic into useable space could increase the value of your home by as much as 25%, particularly if you are adding an extra bedroom and a bathroom.

There are a number of important points to bear in mind: Not every loft can be turned into living space and because every house is different, costs will vary greatly so seek professional advice at an early stage. Bear in mind that you may need planning permission for a loft conversion, particularly if you live in a conservation area, and you must comply with the building regulations. You may need to seek permission from your neighbours before work goes ahead. In England and Wales party walls regulations apply. Its best to seek professional advice before building work goes ahead.

Choose your builder carefully and consider appointing a chartered surveyor to oversee the works. Acting as your own project manager can be complex, time consuming and ultimately costly if you have no previous knowledge or understanding of the construction process. A major extension that involves structural alterations to your home should never be considered a DIY project.

When choosing a builder, keep these points in mind:

    – Shop around and get at least three detailed quotes. If possible, use personal recommendations and check the quality of past projects yourself.
    – Ask plenty of questions: Do your prospective builders have experience of the work you require? How do they expect to be paid - on completion or in stages - and they happy for you to retain some of the money until the job has been done to your satisfaction? Will they agree to independent arbitration should you end up in dispute? Will they accept a penalty clause for failure to complete the work on time?
    – Do use a builder who is a member of a trade association and check credentials with the organisation concerned. You can find professional builders and specialists in your area through the Federation of Master Builders. FMB MasterBond members also meet TrustMark's government-endorsed standards on workmanship and service. They can offer their clients a ten year insurance-backed warranty.
    – Do get written specifications and quotes.
    – Do use a written contract, compile a fully itemised and costed schedule of works and agree a completion date. The Federation of Master Builders provides a plain English contract for use by its members which sets out the agreed work in layman's terms. The JCT Building Contract for Home Owners/Occupiers is also suitable for domestic building projects in England and Wales and copies are available from RICS. The equivalent contract for homeowners carrying out projects in Scotland is published by Scottish Building Contract Committee (SBCC) and is available from RICS Scotland.
    – Don't automatically accept the cheapest quote. Good builders are hard to find and are always busy. It will be worth the wait.
    – Don't pay cash in advance on the promise of a 'cheap' deal.
    – Do hold back a sum of 5% that will be released on completion of the works.
    – Do make sure the builder has a good waste disposal strategy in mind. This will help avoid disputes with neighbours when building work is underway.
    – Do check the building insurance and make sure your insurance company and mortgage company are aware of the work being done - you may need a joint policy with the builder.