Legal Question in Construction Law in Florida

Maybe or maybe not. You will have to look to the contract which was signed for the work. But, even absent a contract, if unforseen circumstances presented themselves, additional cost and time may be agreed to by the client. You need to put in writing the additional pre-existing condition which was found, and provide in writing any additional work or cost that may be incurred which must be agreed to by the client. However, you were not specific whether the delay is "reasonable", so no one can really say whether it is or not. I can think of circumstances in which it may be reasonable and circumstances under which it may be unreasonable.