Hot Topics: Cedar Fence Posts

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Original Post: Western Red Cedar? 4' deep posts?

Toller - Member

My son in Wisconsin is getting prices for a 200' fence. The guy he like is proposing western red cedar. I picture that as brittle wood. Is it durable? How does it compare to pressure treat?

He is also proposing driving the posts 4' into the ground, rather than putting them in cement, saying they are less likely to heave when the ground freezes. Is that reasonable?


clancy - Member

WRC is soft, not brittle. Preservative aspects are over rated. Especially with non heart Wood new growth. Burying it may disappoint.

cwbuff - Member

I don't know about western red cedar but I grew up on a farm that had eastern red cedar fence posts stuck in the ground. The fence posts were decades old. The key is that the post must be heartwood.

I have a split rail fence that has black locust posts stuck 2' in the ground. The fence is 30+ years old and the posts are still solid.

marksr - Forum Topic Moderator

I'm not sure what type of cedar it was but when I built a fence around the place I had in Florida [back in the 80s] I used mostly 4x4 PT post but had few cedar 4x4s that I got for free. For whatever reason those cedar posts had a short life [less than 5 yrs].

Generally the deeper a post goes the more secure it is. IMO concrete is only needed if the ground isn't such that it will secure the post by itself.

XSleeper - Group Moderator

If I was doing it, I'd get a load of crushed rock and backfill the posts with that. I have seen a few posts rot and snap at ground level... but that can happen after 30-40 yrs no matter what.

stickshift - Group Moderator

Rule of thumb is 1/3 of the post buried so 4' would allow for a fence height of 8', if one ascribes to the idea of burying a wood post in the first place.

marksr - Forum Topic Moderator

Hard to build a fence without burying the posts

I like the suggestion to use gravel, the more drainage you can provide under and around the post the better.

XSleeper - Group Moderator

Not gravel... crushed rock. It locks together, whereas gravel easily shifts, like sand.

cwbuff - Member

I have 300' of split rail fence. I put 5 or 6 inches of pea stone in the bottom of each hole to help drain water from the end grain which is where most rot occurs. I then just refilled the holes and tamped the dirt. The fence is 30 years old, has no leaners and no rot.

Soparklion - Member

I'm considering the same project, since I'm not working for the next two weeks... Where are your fences located? I'm in Pittsburgh, Pa. I've got 6 inches of topsoil and clay that the local kids use as modeling clay. It does not drain very well at all.

If I was to bury the posts, should I still coat to protect the base of the post? Anyone use greencoat/copper naptha? Henry Blue Skin is one wrap. Anyone use post saver wraps? - you use a torch to shrink them to the post:

Someone endorses covering the bottom of the post with 30 yr silicone caulk...

Even more interesting is this polymer solution in place of concrete: Fast 2K Post Back Fill by ROYAL ADHESIVES & SEALANTS:

cedar post mounted in the ground

XSleeper - Group Moderator

Interesting product.

If you use treated wood for your posts you always want to make sure that the 4x4s you use for fences are rated for ground contact. Not all treated wood is the same... be sure you check the tags which are required by law to be put on the ends of the wood. Some treated wood is for above ground use only. If you cut a post, you always want to treat the cut end with coppercote or anchorseal 2 or a similar product. And I would suggest putting the cut end up where you can recoat it as needed.