One in four British home improvement projects are under-budgeted, leading costs to soar 4.7 billion above what was initially expected, according to Halifax Home Insurance.The group claimed that people often failed to take into account the full cost of renovating a property, particularly in the kitchen and the bathroom.Kitchen revamps proved to rise the furthest above budget, with 24 per cent of projects requiring further funding, while bathroom overhauls, on 19 per cent, followed suit. Martyn Foulds, senior claims manager at Halifax Home Insurance, said Its interesting to see that the major reason for spiralling costs is often due to homeowners adding extras to a project half way through.Clearly it is all too easy to get carried away with adding more expensive fixtures and fittings as the project unfolds.He added that homeowners should ensure that tradesmen have the necessary accreditations and references for their work, as well as relevant insurance to cover against damage to household items.Good value sinks and taps from top manufacturers like Franke could provide a solid basis for a kitchen revamp, providing all the costs are factored in beforehand.