Discovery after demolition is one of those situations where we have to prepare ourselves for the worst. You don't know what you'll find behind those walls or under those floors. Sometimes it can be a great thing too! Like finding original oak floors underneath that old carpet.
Unexpected conditions can occur in any home; some examples are deficient building structure or unusual sub-terrain conditions. Discovery after demolition is where the Contractor encounters unforeseen difficulties, such as, water damage, infestations, parasites, toxic materials, bad plumbing, bad/illegal wiring or any other items which are not up to code. Also, anything that could not be previously detected by the Contractor by a visual inspection of the site beforehand.