Father in law has seen a property he would like to buy and move into, its currently empty and up for sale. Its got a dilapidated conservatory on the back which he would like to demolish and replace it with a single storey extension, he would like to do this work before he moves in as he hasn't sold his house yet. The question is are there penalties to be aware of tax wise owning 2 properties for a period or is there a time frame for these sort of renovations?