When it comes time to sell up and move on, nearly 40% of us will make improvements to our property to increase its saleability. But how do you avoid over-capitalising and how do you know which areas to improve and which you can leave.

Well, according to research by GE Money Home Lending, the most valuable investment is a loft conversion which  can add around £23,000 to the value of your property.

But if you don't have a loft to convert, other good-value refurbishments are: an extension, which adds an average of nearly £20,000 to a property price, or a conservatory, which can be worth over £12,000.

Gerry Bell, head of mortgage marketing at GE Money Home Lending, said that the property type and location of a house can also determine which home improvements are the best value. So it pays to do local research before you embark on your project.