Legal Question in Construction Law in California

If you build a fence ON the property line, your neighbor and you will have to agree on every detail, either explicitly or impliedly, including design, selection of material, installation and cost sharing (if any). If you build in a couple of inches on your side of the property line, your duties and limitations are a lot more relaxed. You'd have to observe Civil Code section 841.4, largely prohibiting fences exceeding ten feet in height. Also, you'd want to avoid anything that was ugly or unsightly enough to be considered a "private nuisance," i.e., something that significantly impairs the neighbor's use and enjoyment of his property, or its value.