Legal Question in Real Estate Law in California

With the exception of transfers of property, teh law considers verbal agreements to be the same as written one, but it is just much easier to prove what a writing says and engage in a he-ssys, she- says argument.

It's hard to tell what you are asking. Fences attached to what? What aspect of the fence or the attachment might be subject to a "grandfather law"? A law permitting or forbidding what?

Let me make a guess about what you want to know. Neighbor X gave Neighbor Y oral permission to attach Y's fence to X's house (or garage) 11 years ago. You want to know if the agreement is enforceable.

Here are the legal principles applicable to this situation: An oral agreement allowing what would otherwise be a trespass creates a license. Since Neighbor Y had a license to attach his fence to Neighbor X's property, the fence has not been a trespass.

However, licenses are generally revocable at will by the licensor. So, Neighbor X can revoke the license granted to Neighbor Y at any time. Once revoked, the fence becomes a trespass. Y must remove the fence from X's property within a reasonable time or face the possibility of a lawsuit for trespass. However, the trespass would date only from the revocation of the license.

In addition, Neighbor Y has not acquired an easement by prescription. A use by agreement does not become prescriptive and cannot ripen into an easement despite the passage of five years, or any other length of time.

I hope this answers your question, or at least gives you some insight.