Estate agents say a fourth bedroom is the single most valuable feature a family house can have and usually converting an attic is, generally, simpler and cheaper than building an extension.

The most importantly, a loft conversion should not look or feel like an ''add-on'' because if it does it will add little to the value of the house. The staircase is the key to making a conversion look as though it is part of the original house.

Wherever possible the stairway should be a natural continuation of the original staircase so that the transition from ‘old’ to ‘new’ is seamless and within the conversion itself the style should follow that in the rest of the house i.e. skirting boards, architraves, picture rails, ceiling heights etc.