I am thinking of starting some child-minding from home with a friend of mine.(neither of us has any experience with own business) I would like to make some improvements/build an extension in my house but not sure how much if any of the investment I would be able to claim back as a tax allowance? I would like to know before I start the business and also the building works so I can make better financial plans for both. Can someone with experience please help. Thank you