When you buy a car, you test drive it first, right? When you buy an expensive piece of jewellery or clothing, you’ll try it on before handing over the cash. When you buy a house, you take a good walk around it, inspect every corner and tap every wall - probably several times - before taking out the mortgage. However, if you decide to invest thousands or even millions in building your own property, the first time you get to see the fini...