How much does an extra room add to a house’s value
http://thenewdaily.com.au/money/2014/06/30/cost-of-extra-room/
Is it worth paying for an extra bedroom? If it is a new property it could be a case of determining the size of the room, say 16sqm and multiply it by roughly $1,300 per sqm, but if buying established it could cost an extra 100k.