SURVEY
A formal summary of the physical state of a property. We would always advise you to use a qualified surveyor, and we can put you in touch with a suitable candidate; a full structural survey may prove expensive, but at the very least you should commission a "House Buyers' Report".
If you are having a mortgage, your lender will probably have carried out their own survey and valuation. It is always encouraging if this does not show up any problems, but do remember that you cannot rely on it if a problem appears later -- it was carried out for the lender's benefit and not for yours (even though you might have paid for it!).