Fence Posts in concrete or not?

[HighLoader]

Thanks for all the replys! In northern Nevada it can get cold and frost could be and issue. The other property in southern California I don't think it is a problem. Both areas don't get alot of rain, so maybe they will not rust out for awhile. I could use that metal rust primer or coat them with black top. It is a lot of work to pack the dirt around a post. Maybe I could use a 4 inch auger instead of a 6? I am going to do some more testing.

 

[CharlieTR]

I agree with weldingisfun concrete every fifth post.

Do you expect a lot of big cracks in the soil?
Around here the late Summer cracks can swallow a fance post whole. Thats why I would concrete every 5th post.

It would be good if you can find a way to drive the posts in.
A driven post is 1.7 times as strong as a tamped post.

 

[HighLoader]

I understand those post drivers are fast. With that kind of pounding doesn't the top of the post get smashed or mushroom? I am putting nice metal caps on the top of ever post to keep the rain out and give it a finished look.Everyone is going to laugh at me....believe it or not I have been useing a one person "earthquake" gas auger I bought at Lowes for $225 and a 6 inch auger bit for another $100 bucks. I was useing a Gearmore PTO Auger on my other little New Holland TC24da and it was hard to position and would get tippy on some of the slopes. The down preasure was not good either. I did about 30 or 40 holes with it and then tried this little hand held auger and swithch over. I will drill five or more at a time so I don't have to keep pull staring it...even though it starts pretty easy. I use a string line with stakes and it is much easyer and faster to position each hole along the line with the hand held auger than it was with the one on the tractor. I will admitt it is more exercise. Also, if I hit a root or rock bigger than my fist and am day dream'n I could hurt a wrist....I did sprain my wrist one time that way and have been careful ever since. I have thought about getting a hydrolic Auger or a post driver but have got pretty good at doing it this way. So I have a $26,000 tractor and a $16,000 excavator and using a cheap $225 post hole digger!!!

Brian

 

[weldingisfun]

I agree with weldingisfun concrete every fifth post.

Do you expect a lot of big cracks in the soil?
Around here the late Summer cracks can swallow a fance post whole. Thats why I would concrete every 5th post.

It would be good if you can find a way to drive the posts in.
A driven post is 1.7 times as strong as a tamped post.

Only 1.7? All this time I thought it was 1.75 times stronger. Can't believe I've been doing all that tamping for just 1.7. Darn!!


Just funnin' with ya'.

 

[weldingisfun]

I understand those post drivers are fast. With that kind of pounding doesn't the top of the post get smashed or mushroom? I am putting nice metal caps on the top of ever post to keep the rain out and give it a finished look.Everyone is going to laugh at me....believe it or not I have been useing a one person "earthquake" gas auger I bought at Lowes for $225 and a 6 inch auger bit for another $100 bucks. I was useing a Gearmore PTO Auger on my other little New Holland TC24da and it was hard to position and would get tippy on some of the slopes. The down preasure was not good either. I did about 30 or 40 holes with it and then tried this little hand held auger and swithch over. I will drill five or more at a time so I don't have to keep pull staring it...even though it starts pretty easy. I use a string line with stakes and it is much easyer and faster to position each hole along the line with the hand held auger than it was with the one on the tractor. I will admitt it is more exercise. Also, if I hit a root or rock bigger than my fist and am day dream'n I could hurt a wrist....I did sprain my wrist one time that way and have been careful ever since. I have thought about getting a hydrolic Auger or a post driver but have got pretty good at doing it this way. So I have a $26,000 tractor and a $16,000 excavator and using a cheap $225 post hole digger!!!

Brian

My wife and I used one of those Earthquake augers to put in 1.5 miles of posts, Now we have a tractor and PHD. Still have the Earthquake, just in case I need to sink a hole somewhere that tractor can't go.

Around this part of the country we stuff newspaper down the top of the pipe/post about two or three inches (depends upon the length of your fingers) and then set a ball of wet concrete mix (Quikrete) on top of it. Use enough concrete mix and you get that nice finished rounded top you want. It is a whole lot cheaper than those metal caps. Think about it.

 

[oldhippy]

I install iron fences. We use concrete. A oldtimer showed me the best way to do the concrete. You pour about a coffee can of water in the bottom of hole. Then set in pole pour in part of you concrete, tamp it down like you did the dirt. Then pour in more concrete untill the hole is full. The pole will then be set. If your ground is real real dry pour some water in ground around outside of hole. The moisture will get to the concrete through the ground. The next day concrete will be set. Because of the slow setting of concrete it will no shrink back from pipe. When it shrinks back from pipe it will leave a pocket for water to stand and rust sooner. big dan

 

[Sully2]

I have started fencing our 5 acre and 20 acre property, the perimiter and interior. I am using 2,7/8s steel oil well tubing for the posts. I have been drilling 2 foot holes and then setting them in concrete. Yesterday I tried setting a couple without concrete. I used a steel rod to pack the dirt in around the post. I was suprised how secure it was. Without the concrete, will the posts loosen and lean over? Without the concrete to protect the post how long will the post last? Can I coat the post with something before I put it in the ground? My hope is that I can get a good 40 years or more out of these posts so when I am in my eighties I will not have to do this all over again! Anybody out there with some advice? Thanks

If you ever do get a freeze down below 2 feet...they'll pop out of the ground. Thats not deep enough. It also DOESNT ALLOW enough "contact surface" ( i.e. "footprint) with the surrounding soil.

I took a course once on constructing "Timber frame homes"...and this is what they taught. They said that 20% of the "sticking out length" was suppose to be IN the ground with a MIN of 30" and ALWAYS below any frost line. Also the deal on concrete around a post was this.

Bore the hole..and on the bottom of the post insert a "pin" that goes THRU the post and sticks out about 4" min on both sides ( with a metal post you could weld a piece of rebar across the bottom to do the same thing) Put the post in the hole and pour enough concrete in to cover the "pin" by about 4 inches of concrete...plumb the post and brace it and let the concrete harden up. What you wind up with is a post with a BIG WASHER attached to the bottom of it. Fill the hole with TAMPED soil and make sure its tamped well.

 

[gerard]

I agree with weldingisfun concrete every fifth post.

Do you expect a lot of big cracks in the soil?
Around here the late Summer cracks can swallow a fance post whole. Thats why I would concrete every 5th post.

It would be good if you can find a way to drive the posts in.
A driven post is 1.7 times as strong as a tamped post.

Fencing that much I'd also consider a post pounder. They have a cap that goes over the top of the pipe and the weight actually hits the cap, not the pipe directly to prevent mushrooming. All commercial fence companies that install chain link fence with metal posts ( which is close to what you're doing with the oil pipe) use a pounder. It's quicker, tighter, and you can plumb as you go. (The pounders articulate in all 4 directions so you drive at any angle you want). There's also no backfilling, tamping etc. When you're done pounding you're done. I bet you can do a pole every 5 minutes with a pounder! BYW - I echo the other sentiments about your land - beautiful!

 

[Sully2]

Fencing that much I'd also consider a post pounder. They have a cap that goes over the top of the pipe and the weight actually hits the cap, not the pipe directly to prevent mushrooming. All commercial fence companies that install chain link fence with metal posts ( which is close to what you're doing with the oil pipe) use a pounder. It's quicker, tighter, and you can plumb as you go. (The pounders articulate in all 4 directions so you drive at any angle you want). There's also no backfilling, tamping etc. When you're done pounding you're done. I bet you can do a pole every 5 minutes with a pounder! BYW - I echo the other sentiments about your land - beautiful!

My farmer friend has one of those and I got to watch him use it this past fall. I have to agree 100% with ya. The "proper length" piece of pipe...driven down with one of those makes concrete around the post a waste of $$ and effort.

 

[patrick_g]

Concrete will definetly help hold the posts more securely.

Under what conditions do people ordinarily set T-posts in concrete? Why would pipe posts be less sturdy without concrete than T=posts without concrete?

If the pipes are set deeply enough then once the dirt settles in around the pipe posts thay will be as or more secure than T-posts if you set then as or more deeply. Tamping the dirt will firm them up without a wait for them to naturally settle. Concrete is more important on high stress applications such as stretch fixtures (H braces and the like), corner posts, posts with gates attached, areas where stock is handled and may take a run at the fence, and similar applications.

I'm not saying concrete might not make your posts more secure but that typical barbed wire fences with T-posts don't use concrete on the T-posts and you shouldn't need it either unless you have special circumstaces.

If you are not using barbed wire and are fencing buffalo or separating bulls, or similar applications where the side loads will be considerably more that a typical barbed wire cattle fence, then concrete is a cost effective consideratioin as are side braces and or all welded pipe fence or with cable or sucker rod horizontals.

I admire the fences at the Wichita Mountains Wildlife Refuge near Lawton, Oklahoma where herds of buffalo, elk, etc. are fenced in. Not T-posts and barbed wire!

Pat