Cement or gravel?

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73fj

Tho at sumbitch in ayer!
Joined
Mar 16, 2003
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Location
Grande Prairie, Alberta, Canada
I'm building a patio and will be sinking some 6"x6" treated posts for a trellis. What would be best to hold the post, fill the hole with cement or pack gravel in there? Any thoughts?
 
I assume by cement you really mean concrete. I would use concrete but make sure that the bottom of the post is touching dirt so that any water that infiltrates the post due to rain can exit the bottom and not sit flooded in a concrete bathtub. I normally set the post in the hole and add a bit of dirt around the edges and tamp this down so that I know that I have at least an inch or two of packed dirt around the bottom edge. Then pour in concrete and level the post.
 
Cement is Concrete if your speaking Canadian english :D, I was thinking the gravel method would allow better drainage, but not sure how tight it would hold the post.
 
You need cement/concrete. It will move otherwise.

When I planted our mailbox I just dumped two bags of concrete in the hole (dry), topped it off with dirt and let the moisture and rain set the concrete. Redneck, but it worked.
 
Cement is the gray powder stuff in concrete. Kinda like the flour of a cake mix.

Anyway, I personally wouldn't like having the PT post embedded in the ground like that. I know you can get better PT that is OK with constant contact like that, but eventually even that will fail and start to rot, right at the ground level. I think you're better off setting sonotubes and anchor bolts, with anchor plates that bolt to the top of the concrete pillar, like you were doing a deck support. This will also allow you to easily replace the wood if it gets damaged your you want to modify it later.
 
KLF, thats not a bad idea, hadn't thought of doing it that way.:hmm:
 
I know you can get better PT that is OK with constant contact like that, but eventually even that will fail and start to rot, right at the ground level.

That only happens if you encase the post completely in concrete (the part in the ground that is). It won't rot if you have the bottom exposed to dirt.
 
the post will still rot when encased in concrete, especially if the bottom is exposed to dirt

Set a post saddle in a concrete footing and then bolt the post to that
 


This
 
Today's week old trees cut for lumber and the new safer crappy pressure treatments fail miserably compared to 20 years ago.
I'd go with the others on small diameter sonotube and bolt the wood on top.
 
I'm guessing that your climate is fairly arid and that you won't have a lot of runoff in this area - unless Grand Prairie is a lot more coastal than it sounds. You're not supporting a deck or any weight other than a trellis right?

Just tamp the post and forget about it.

Concrete will only make the post rot quicker as it holds moisture no matter if the bottom of the hole is open or not. We just set 30 10x8x30' PT posts for a new hay barn and tamped native soil is all we used. Barns have been standing this way for 30+ years even though posts are very close to the drip line of a rather large roof. On the other hand, a fenceline that has railroad ties set in concrete in the same timeframe is completely rotted off at ground level where the concrete meets the post.

Same happens with steel posts. The only bulletproof method is to sleeve the post with a larger diameter PVC collar an fill this with road tar.
 
Nope, no deck, just something for shade and some vines to climb. I decided to use saddles because the one hole I drilled had about two inches of water in it this morning :mad: :bang: then I found out that the two foundation walls I was measuring off of were not square, double :bang:, so I eyeballed it and I came out 1/2" from square, considering the size and nothing square to measure off of, thats close enough for me. I appreciate the input guys :beer:.
 
Nope, no deck, just something for shade and some vines to climb. I decided to use saddles because the one hole I drilled had about two inches of water in it this morning :mad: :bang: then I found out that the two foundation walls I was measuring off of were not square, double :bang:, so I eyeballed it and I came out 1/2" from square, considering the size and nothing square to measure off of, thats close enough for me. I appreciate the input guys :beer:.

I plan on doing the same thing on our patio area. Take some pics :D
 

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