House prices have risen once again for British homeowners, who may have already taken steps to boost their propertys value by giving their kitchen a makeover.The Nationwide house price index revealed that the value of a typical home rose by 1.2 per cent in May.According to the survey, this makes the average value of a house 154,016, an increase from 151,861 in April.Kitchen refurbishments could go some way to improve this figure. Recent research from Halifax General Insurance discovered that over the past 12 months, the average amount spent on home improvements was 5,300.Britons spent the most on their kitchens, forking out around 6,300 to give the room a makeover.Commenting on the increase in house prices, Martin Gahbauer, Nationwides chief economist, said At 154,016, the average house price is still 11.3 per cent lower than a year ago, although this marks a significant improvement from the annual decline of 15 per cent recorded in April.