Legal Question in Real Estate Law in California

Your answer is quite fact-sensitive, but at least one theory of damages would be the cost to replace the barrier, especially if this is what you need and intend to do. You might want to obtain written estimate(s) from one or more contractors or suppliers from whom you could obtain the replacement. If there were "dollarizable" harm to you property while the barrier was missing, this could be added to the cost to replace. Small-claims evidence and proof procedures are rather informal the the judges less than predictible, but in general it's a good idea to ask for only the damages that you can substantiate through witnesses, written evidence, or similar means, rather than by asking for numbers picked out of thin air, or based on hurt feelings or a desire to punish.

Small claims are for cases under $10,000. If your damages are around that you should consider getting a lawyer and going in limited civil court. Small claims court is a court of equity and you cannot appeal it if you lose. Thus get an estimate to replace and if its near the court's limit you ought to weigh your options.