Building a fence from pressure-treated wood. What happens when the posts dry/shrink?
What do you think about this?
I plan to build a fence made of pressure-treated timber.
But now I'm starting to wonder what will happen when the posts dry/shrink (pressure-treated wood has expanded).
If I attach the fence rails with L-brackets (as in the top image) to the sides of the posts, the fence rails will be pulled towards the center of the post when it shrinks. And the fence rail will pull on the next post (which also shrinks) and so on.
If each post, which is 95x95, shrinks 2-3mm, it will be most noticeable on the outer posts since they will be affected by the entire length shrinkage of the fence.
So then maybe I instead need to notch each post and let the fence rails meet, so the total length of the fence won't shrink since rails (probably won't) shrink in length. But then you'd be exposing the core of the post to water.
I plan to build a fence made of pressure-treated timber.
But now I'm starting to wonder what will happen when the posts dry/shrink (pressure-treated wood has expanded).
If I attach the fence rails with L-brackets (as in the top image) to the sides of the posts, the fence rails will be pulled towards the center of the post when it shrinks. And the fence rail will pull on the next post (which also shrinks) and so on.
If each post, which is 95x95, shrinks 2-3mm, it will be most noticeable on the outer posts since they will be affected by the entire length shrinkage of the fence.
So then maybe I instead need to notch each post and let the fence rails meet, so the total length of the fence won't shrink since rails (probably won't) shrink in length. But then you'd be exposing the core of the post to water.
Pressure-treated wood often has a high moisture content upon delivery, so yes, the wood will shrink somewhat as it dries out. However, I find it difficult to see that this would cause any major problems. I would say that both options work. I don't know how you envisioned the appearance of the fence otherwise, but another option is to just nail/screw the rail to the posts.