Setting fence posts in concrete/ bad ????

EddieWalker · Dec 2, 2004

Interesting thread, but without a solid conclusion, I'm still mystified what is the best method.

I'll be putting in some fence this spring and still trying to decide on wood or metal for my corners and braces.

I've got a feeling both will work just fine and it will come down to cosmetics.

I've heard the theory of the post shrinking over time and catching water in that space and rotting out the post, but I've looked for it over the years in posts I cemented in, and haven't seen it yet. I figured I'd put some silicone in the gap to stop just such a thing from happening.

I have seen this space in packed posts and had to repack them after a year. I'm not sure if it was from movement or the moisture in the fill dirt drying out or some other factor.

I don't think it was the wood shrinking that caused the space, cause I've also seen in in some plastic fence posts that were packed in.

It seems the more answers to the question, the more questions I have.

Eddie Walker

MarkLeininger · Dec 2, 2004

Please use all the different methods proposed here on each of your posts and repost (no pun intended) to this thread in 25 years with results.

Freds · Dec 2, 2004

( Please use all the different methods proposed here on each of your posts and repost (no pun intended) to this thread in 25 years with results )

Well if he's going to conduct a scientific study /forums/images/graemlins/laugh.gif ... A friend of mine staples felt paper to his fenceposts (4x4 PT) before he sets them in concrete.

Dargo · Dec 2, 2004

Aww heck, just use 4X4 stainless steel square tubing and plant those posts in concrete. It might be a wee bit spendy, but it ought to last. /forums/images/graemlins/wink.gif

FL_Cracker · Dec 2, 2004

All of need to think hard about all this fence post debate. If we can install a PT post in concrete with a little gravel on the bottom and have it come out set nice and tight, then after 12 years see very little rot then what are worried about. I have a hard time paying extra for galvanized nails because I don't think I'll get my moneys worth. (Joke)

To sum it all up, I happy with an installation method that will make my fence post last 20-25 years. (And at the same time make them set up nice and tight so I don't have a fence that looks like I was drunk, blind or crosseyed when I installed it.)

Gravel, concrete and PT posts for me.

Henro · Dec 3, 2004

If it were me...

I would not fear using concrete around a pressure treated post...

But why would I want to spend the extra money for the concrete?

Maybe because I want the post to start out exaclty where I put it? Or because I want the post to become able to support some kind of side thrust ASAP?

Other than that, posts set in ground and back filled with earth that is tamped in a bit seem to hold pretty darn well after an initial period when the ground around them settles in.

I would not bother using concrete unless there was a real need for it. I would not fear using it if I felt the need to use it. I have some posts set in concrete that have at least ten years under their belt and look real good.

I also have some non pressure treated locust posts that have 15 years under their belt, and still have life left in them.

Bottom line in my mind is why spend the money on sacks of concrete if you don't need it? And why worry about it if you do need it?

Ozarker · Dec 5, 2004

I don't know the answer but tend to agree that it is the chemicals in the concrete that accelerate the rotting process.

My deck is on 6X6 cedar posts. It was built before I bought the house but the guy that built it lives next door. The posts are sitting on tamped gravel 3 feet in the ground but the pored concrete patio is pored against the posts. I am going to have to tear the whole mess down and rebuild the deck after only 12 years because those cedar posts are rotting away at ground level where the concrete is against them.

eee · Dec 5, 2004

I am going to have to tear the whole mess down and rebuild the deck after only 12 years because those cedar posts are rotting away at ground level where the concrete is against them. 

My house has cedar all over it and my side step/old porch was built out of cedar(1988) and we had the 4x4 cedar posts set in dirt ,the post rotted off and no concrete was used it was just tamped in dirt. I have since removed the side step and built a new wrap around porch.

beenthere · Dec 5, 2004

All 'cedar' isn't the same. Only the heartwood of the cedar tree (of which there are many) is resistant to rot. If the posts are mostly sapwood, then they will rot in the ground about as fast as any wood. Hard to know ahead of time what cedar one is dealing with too. No easy answers. /forums/images/graemlins/frown.gif