I have often heard many people say that they did not have a contract and/or change order when they actually meant that they did not reduce their agreement to writing and/or sign a written document. Whenever someone performs work in exchange for a promise of payment, they have a legally enforceable agreement. The question is whether the contract was verbal or written.
There are two areas where the issue of not having a fully executed written agreement repeatedly arises in construction. The first is when the parties exchange a written contract but do not fully execute it, and the second is when the parties ignore the requirement in their contract that any changes in the work only be performed pursuant to a written change order. In both these cases, there can still be an enforceable verbal contract.
As you might expect, having a written contract is often better than a verbal, which is why there are many publicly available forms that can be obtained for construction projects. The American Institute of Architects (AIA) produces the most well-known and widely used forms of agreement, but there are competitors that offer similar (if not better) products. The point is that there is no excuse for not having a signed written agreement for any construction project,