Does setting treated wooden posts in foam (the kind that's designed for setting posts) give them some protection from rotting?
Is it easier to replace a post that's been set in foam that a post that's been set in concrete?
I want to build a pergola and I'm debating how to set the posts.
Options:
1. Bury in the ground
2.. Set in concrete
3. Set in foam
4. Pour a concrete pad and set the post on a post anchor on top of the pad
My experience with cedar and treated lumber in this climate is that it dry rots in about 10 years when buried. I think posts last longer when set in concrete, but when they must be replaced, it's a pain in the neck. Posts set in post anchors on top of a concrete pad hold up well, but they must be temporarily supported during construction.