[gotboost]

Ok...what is the trick to setting a rock solid 4x4 PT 8ft'er?

 

[Just Bill]

Deep hole, min 2', use a backfill material that will pack, like crusher run, not pea gravel. Dry concrete mix is often used, it will harden with ground moisture. Tamp backfill every 6" or so, and fill to about 2" from the top, then dirt for grass. Only use posts treated for below ground burial, not all are.

If these posts are to support a deck, porch, etc., they need to be min 30" (in our area)deep, and the bottom needs to be belled out so frost won't cause them to heave up.

 

[tcurtisfree]

posts for a deck with high water table

I am putting in 16 foot post 36 to 42 inches deep. I ran in to high water table so I have standing water in each hole. I was going to put gravel in bottom of hole, put post in, then pour in dry cement and let the water from the earth set the concrete. What do I do with the standing water?
tom

 

[curapa]

Ok...what is the trick to setting a rock solid 4x4 PT 8ft'er?

As far as setting the post goes, dig your hole about 26" deep. I like to balloon the bottom of the hole depending on what type of soil I am setting in. Backfill and set the post in the hole and add concrete (40-60 lbs is usually good).

If you want the best quality from a pressure treated post, allow the post to dry out somewhere like a garage. Keep it off the slab with scrap wood supporting every couple of feet and as flat as possible. If you have several posts then stack them up to help prevent twisting.

The rapid drying of the wet posts when placed in the sun is the main cause of the warping, bowing and twisting seen in pressure treated posts.

If you want a post that will not move when pushed on or you want to hang something from it then you need to increase the post size to a 6x6.

 

[gotboost]

we have been digging 24in's deep then adding 80lbs of cement,and we still get a few post that are loose,when we re-dig them there is very little cement left in the hole where does it go?doesn't seem to matter much if the ground is wet or dry the post still come loose..

 

[RippySkippy]

While it's done a lot (as shown by the responses here), generally it's not a good idea to set post in concrete. You'll get the same results with well tamped rock fill...I use a piece of oak, 1-1/2" square for my tamp stick.

You say you're supporting a fence...what type? How tall?

Here's some different opinions:

http://www.sawmillcreek.org/showthre...t=12478&page=2

"Pressure-treated pine posts are ideal for fencing because they resist rotting. These posts can be set in concrete to ensure their stability. Many companies offer an extended warranty on their pressure-treated posts to guarantee their quality." - http://www.americanfenceassociation....ood/index.aspx


"Should all posts be set in concrete?
We recommend that all posts be set in concrete in accordance with local conditions and standard building practices. Posts that are not set in concrete will eventually lean due to wind and weather. Check your local building codes through your city or county government for further details." - http://www.millsteadinfo.com/faq.aspx

"The post can be placed atop a concrete pier, bolted to a steel anchor, or it can be set in the concrete. Placing the post into the concrete pier adds strength, but it is more susceptible to rot." - http://canada.contractors.com/trade/...e_install.html

"Posts that weren't properly treated or set in concrete typically rot away at ground level." - http://home.howstuffworks.com/how-to...wood-fence.htm

"Why are we so concerned about longevity of this treated lumber post? Because treated lumber does not last forever. I have seen treated lumber begin to decay after less than 20 years of exposure to the elements. Anything that can be done to reduce the amount of water next to the post will surely reduce the chances of the preservative being washed away." - http://www.hammerzone.com/archives/d...nd/footing.htm

"Question: Is it ok to put a deck post into concrete instead of using an anchor, and if so,will the post not last as long as using an anchor.frost level is 36", how much of the post should be buried in the concrete.will this way be stronger(less sway) than using an anchor. thanks
Answer: Hi Ray. Definitely better to put it in concrete. Should give you minimal sway depending on how high the post is above the ground or deck. I am not too sure about frost levels as my life in the U.S. has been spent in California, Florida and south east Georgia. 24" depth into the ground should be quite O.K. Hope this helps." - http://en.allexperts.com/q/Decks-3464/deck-support.htm

 

[curapa]

RippySkippy, you are correct that a post set in concrete is not the most ideal situation due to the moisture content. I have found that the longevity of tamped rock does not equal that of concrete in the coastal soil here. I did have a friend in Ohio that said rock fill was common practice there, different locations equal different construction practices, codes and such.

In my climate I expect my posts that are set in concrete to last 20 + years.

 

[DUDE!]

worked with an older fella, if your arms weren't twitching, and you could still breathe, you didn't tamp it enough, do it some more, and no rocks in the backfill, We were working mostly sandy soil, set 4x4 fence posts in at least two feet.

 

[Thurman]

If you were to set fence post with my wife's Grandad (RIP) then you would have to wait for him to observe the calendar and moon phases. HE would not set fence post on certain phases of the moon. I am here to testify that he taught me that there are certain days of the month when you can dig a hole, put the dirt in a bucket, place the same dirt back into the hole and not have enough to fill the hole. There were certain days of the month when you can did a hole, put the dirt in the same bucket, place the dirt back into the hole and have some left over-after tamping. That man could dig and set fence post on certain moon phases, using only dirt for backfill and you could not knock them over with an NFL lineman. He only used yellow poplar for fencepost. I have seen some of them he put up in the '30's and '40's that are not rotted at all. Don't even ask me about him finding water underground with two willow branches. He never failed, never ever. He could even tell you by a woman's attitude if it was a good night to sleep on the couch or the bed . Mr. Leland I'll miss you. David

 

[macky1953]

:laughing:

I am putting in 16 foot post 36 to 42 inches deep. I ran in to high water table so I have standing water in each hole. I was going to put gravel in bottom of hole, put post in, then pour in dry cement and let the water from the earth set the concrete. What do I do with the standing water?
tom