8. If your builder does not supply a contract, you could draw up one yourself setting out the work to be undertaken in as much detail as you can, with timescales etc. to be signed by both you and your builder. Or you could download a contract free of charge from the Federation of Master Builders website . If you ask for extras after the work has started, check how much they are going to cost before proceeding.

9. Be wary of paying in cash and always make sure you get receipts. If you can, it is worth making an initial deposit with a credit card as this will give you added legal protection. For work costing between £100 and £30,000, your card provider will have equal liability with the contractor for making sure the work is done properly. Do not pay the full price for the job upfront, pay as parts of the work are completed, holding back at least 5% until the whole job is finished.

10. To keep costs down you may want to do some of the finishing off work yourself, such as decorating. Steer clear of the electrical work, though, as new rules which came into force in January 2005 mean that work must be carried out by a competent person and will be covered by building regulations. If you use a registered contractor, you will be sent a building regulations compliance certificate by the registration scheme operator.

11. If your extension needs approval under building regulations, remember to keep the final certificate to confirm that the work is okay so you have it available for future purchasers of your property.

Related Internet Links

• Property guides

A guide to househunting on the web

Househunting goes high-tech: technology is transforming the way we search for our next home. Our buyers test-drive top property websites

• A step-by-step guide to selling your home

• Gumtree founder, Simon Crookall, puts his £1.5m home for sale online

BACKGROUND

• Why can’t we sell our home?

• ‘I didn’t want a profit; I just wanted out’

• How to sell your home in a hurry

BACKGROUND

• Overseas property: where, how and what to buy

• How to get onto the property ladder

• Guide to buying above a shop

BACKGROUND

• How to sell your home

• Buying a property at auction

• Home improvement

• Eco homes

• Step-by-step guide to buying your first property

Related Links

• Ten things you need to know about... buiding an extension

12. Finally, remember to inform your home insurance provider before you carry out any major home improvements such as a loft conversions or home extension, otherwise you may find claims for any damage to the house while this work is going on will be rejected. Add legal expenses cover to your home insurance policy as this may pay for any disputes which could arise with builders and other traders.

CALCULATING THE TOTAL COST OF EXTENSIONS AND CONVERSIONS

House extensions

Single storey with one window, 3 m x 3m: £15,200 to £18,500

Two story with two windows, 3 x 3: £25,000 to £32,600

Loft conversions

With Velux or similar windows, 4m x 5m: £14,100 (2 windows) to £18,500 (4 windows)

With dormer windows, 4m x 5m: £24,900 (2 windows) to £39,100 (4 windows)

Basement conversions (upper price includes tanking to walls and floor)

3m x 3m: £7,400 to £16,300

4m x 6m: £10,300 to £26,000

Source: www.bcis.co.uk/propertymakeoverguide. Prices as at 1st Quarter 2008.