Legal Question in Real Estate Law in California

If the wall is built right on the property line, then you both have the same rights to alter it, so you could not ad to its height without the other owners approval. You probably are doing something that he does not want, as you would ask him first otherwise. Would you like the roles reversed? Also, will that make the walls too height under your local zoning code so legally it can not be done?

Also, exceeding ten feet gets you into the statutory presumption that the fence or wall is a spite fence and therefore a private nuisance. Civil Code section 841.4.