What does Subject to Survey &Contract mean?

It is important to note the fact that until the contracts have been exchanged in a transaction, English states that there can be no legally binding action. Only after the contracts have been exchanged, follows the completion which is the last decisive phase of a transaction.

Making something being “subject to survey and contract” basically means that up until the exchange of contracts you may make up your mind and step out of the transaction (i.e. you found a property that is cheaper and more convenient so you would rather prefer that). On the other hand, the seller himself may reject your offer because he has found a purchaser who offers even more for the same property.