Legal Question in Construction Law in California

It is if it contains all the requisites of a construction contract under the Business and Professions and Civil Codes, AND there is proof of acceptance and agreement by means other than a signature.

An answer to this question must be cautious and qualified. Certainly a home-construction contract should be, ideally, written out in detail, plans attached as exhibits, and signed by both parties with fully-executed counterparts being exchanged. However, on smaller projects, that often isn't the way it works.

An enforceable contract is created by offer and acceptance. Law school students spend weeks in contracts class learning the basics of these concepts. When there has been a valid offer, timely accepted in a manner invited by the offer, a contract is formed. If there is no writing at all, the result will be an oral contract - enforceable in most, but not all, contexts.

Further, unsigned written contracts will be enforced if (a) the court or jury finds that the parties intended to be bound, i.e., that there were an offer and an acceptance, and (b) no law requires that the contract be signed by the party against whom enforcement is sought. A written agreement not yet signed may be enforceable if the parties orally agree to the proposed written terms with the intention that the oral agreement should thereupon become binding. Magness Petroleum Co. v. Warren Resources of Cal., Inc. (App. 2 Dist. 2002) 127 Cal.Rptr.2d 159, 103 Cal.App.4th 901.

The Business & Professions Code contains provisions here and there requiring signatures by the contractor. Cases involving those statutes seem generally to reflect that the contractor will get paid the fair value of its work, materials, etc. under a quasi-contract or "quantum meruit" theory.

In sum, a court will probably find a way to honor the intentions of the parties to an imperfect document rather than treating it as a complete nullity.