Legal Question in Construction Law in California

First, does the contract contain any provision requiring the contractor to obtain a "go ahead to purchase material" or, by not containing such a provision, was the contractor engaging in reasonable preparatory measures when he committed to the material? I'd guess more likely the latter, but if it does indeed contain a "wait for the go-ahead" provision in one form or another, the contractor is stuck with the bought-too-soon material. In the absence of such a provision, it is less clear what the result would be in small-claims court, because you have a clash of two legal principles: the one the contractor is counting on, i.e., that he has a right to charge you for costs incurred in preparation for your job such as purchasing or fabricating special materials that can't be returned or otherwise used; and the one that supports your position, i.e., that the contractor cannot lawfully take a deposit exceeding 10%. I'm leaning toward guessing that a small-claims judge would rule in your favor, in that the statutory limit on deposits is a primary and more significant rule that the contract-law principle that costs incurred in preparing to carry out a contract should be reimbursable if the contract is canceled.