# cement and cedar posts



## yankcollector (Jul 6, 2006)

I understand from what I read that putting 4 x 4 cedar posts directly into concrete is a no no in the sense that it causes the posts to rot prematurely. How about this option: coating the bottom of the posts (that would be in contact with the cement) with a roofing asphalt thus keeping the wet concrete from contact with the posts? Any input????????


----------



## Square Eye (Jul 6, 2006)

Cedar is a fairly soft wood. Expansion and contraction will cause the post to work against the concrete. While roofing asphalt will isolate the post from direct contact, it will also seal the bottom of the post. Moisture will collect at the bottom and will not be able to escape. 

I believe the correct way to handle this, is to wrap the post in black felt builder's paper, set the post plumb, tamp rock into the hole a few inches deep, then pour concrete. Cut the paper just above the concrete or the ground level after it sets. You can drive framing nails one inch into the post after you wrap it to add more anchoring power.


----------



## Daryl in Nanoose (Jul 7, 2006)

Square Eye said:
			
		

> Cedar is a fairly soft wood. Expansion and contraction will cause the post to work against the concrete. While roofing asphalt will isolate the post from direct contact, it will also seal the bottom of the post. Moisture will collect at the bottom and will not be able to escape.
> 
> I believe the correct way to handle this, is to wrap the post in black felt builder's paper, set the post plumb, tamp rock into the hole a few inches deep, then pour concrete. Cut the paper just above the concrete or the ground level after it sets. You can drive framing nails one inch into the post after you wrap it to add more anchoring power.


 And in addition to what Square Eye said
*Also, taper the concrete at the top so the rain runs off away from the post. After a year and the cedar has shrunk you may want to caulk this to help keep the water out.*


----------



## glennjanie (Jul 7, 2006)

*Or*, when the concrete is poured and you have trowelled it once, take a 16d nail and rake out a line against the post. Then, when the concrete is set, fill the rake with silicone caulk.
Glenn


----------



## cdejacob (Jul 14, 2006)

This may depend partly on what the posts are for...

If they're fenceposts, and the concrete is below the frost line, you may not have much to worry about.

If they're posts meant to support a structure like a deck, I'd leave the post seperate from the concrete altogether.  Concrete footings first, and then piers on top of those (commonly with tubular cardboard forms), an anchor bolt in the top of the pier, then a structural galvanized spacer fitting (like a simpsons strong tie) to allow air circulation, and finally the post attached to the fitting with deck screws.

Chris


----------



## PaPaDan (Jul 15, 2006)

I agree with Chris on this. Any concrete around the post will cut its lifespan in half. For fence posts just put the post in the ground. and for a deck or structure put the post on top of a footer, isolated from the concrete with a strong tie. I learned the hard way a long time ago with Cedar and Treated fence posts. No Concrete.


----------



## asbestos (Jul 16, 2006)

geeez all this fuss for fence posts? use treated apply end cut solution to all cuts and if a post or 2 rots in 20 years replace it. Any way around it wood in the ground will rot when it rots. For srtuctural do like what was said footings then wood.


----------

