Prior to turning it into a buy-to-let, I had a lot of work done to a property in the form of a loft conversion. Accordingly, the value of the house has increased significantly. Are these costs taken into account when determining the capital gains tax (CGT) on the property when I decide to sell (sale price minus purchase price)? 

Arthur Weller replies 

A loft conversion is a valid form of enhancement expenditure, because it is 'expenditure on the asset' and it improves the value of the property, as you have written. Consequently, it is taken into account when determining the future CGT on the property. See HMRC’s Capital Gains Manual at CG15180.