Legal Question in Construction Law in California

Re: Special orders

If the contract calls for a down payment before work starts, the down payment cannot be more than one thousand dollars ($1,000) or 10 percent of the contract price, whichever is less, for a home improvement job or swimming pool, excluding finance charges. There are no exceptions for special order materials.

However, it is not clear if what you have is a home improvement contract. If you are ordering the doors yourself from a supplier, then there is no regulation on the deposit. If you working with a contractor than wants a 50% deposit, you should find another contractor that will comply with the law.