Not sure if this is the correct forum, but figured that there'd be more people with good ideas on this one.

We plan to burn an old building down that is next to our feedlot. There are a couple of wooden fence posts, set in concrete, within 6 ft of this building. What would be a good way to protect these posts from burning? My first thought would be to make tubes out of some sheet metal, about 6-8" larger in diameter and place around the posts to insulate them from heat. Any better ideas?

Thanks.