A Building Report (or Builder Report) is a report that you may get on a property (sometimes this can be required by a bank or lender), that can tell you the condition of the property or what repairs, issues or defects there may be; these can include but are not limited to; leaky building, structural issues, problems caused by deferred maintenance (such as weatherboards rotting due to peeling paint) and areas where there is damp or mould, roofing or guttering problems.
A Builders Report can be undertaken (and typically is) by a licensed building inspector or suitably qualified individual.
Often a building report/inspection can be complex, so it may be advantageous to go through this report with your lawyer or another professional with an understanding of the building industry.