Do wood fence posts need to be set in concrete?

Question

i live in michigan and want to install about 450' of 6x8 wood fence. Since I am going to have to use about 58 4x's I am trying to see if I need to concrete every single one. My idea is to concrete the end and corner posts deeper and then use a gravel footing and backfill with sand for the rest. Will this hold up in the high wind and snow we get in the winter? I will be installing them about 1/3 the overall length of the 4x4 into the ground.

Answer 1

Depends on how soon you want to do the whole job over again. Setting the posts in concrete is by far the most durable method. Any other method will decrease the life span of your fence dramatically.

Answer 2

You're better off with the socketted spikes. Over here they sell by the name of Fencefasts. The reason is that even tanalised wood will eventually rot, and if you need to change a post it's easier to take it out of its socket (they tighten up with a nut&bolt) than to break it out of concrete.

Do you need every post to be a 4x? With a deep spike you could probably manage with 2xs for the most part and 4xs at corners and ends; the slimmer posts would flex in the wind rather than breaking and make the fence stronger. An open design of panel rather than solid - possibly with hedging alongside it - would let the wind through, so keeping the fence up longer.

Answer 3

I asked many questions before i started my past fence build. I recommend calling elect. company first, they will come out and mark your house feeds. They do it free in Ohio, I have seen people not do this and who knows what may be waiting down under ground for you. Most homes have two 110 v. lines and one neutral, thats how you get your 220 volt service. It may be only 110 volts BUT there is 200 amps pushing it through the lines, The amps can KILL you very quick so be careful.

I recommend a 30" hole for each post 6 ft. high. Put at least 6" of #2 stone in each hole., like a large marble. The stone is to keep the post off the dirt. If you put even treated wood in the ground it will rot after a while. Wood has the ability to soak-up water, it must drain at the bottom or ROT Starts.

Dig hole 8" wide by 30" deep for a 6' tall post. Place mixed cement in the hole but not to  earth level. Stop 3 to 4" below ground. The grass will NOT grow on the cement so leave a little dirt for it to root. Best to brace each post on two sides with a 2" x 2" brace. Level post, then nail brace, last add the cement. Let sit at least 24 hr's at 70 digress.

I did the above in Ohio and built a fence for a 25 acre lot that is still standing 16 years later. A little time to build it right and you will have a great fence...

Answer 4

you can get metal spikes with a square opening at the top to take fence posts and sink them into the ground.

I expect concrete would last longer though!

Answer 5

not always, as above you can get metal spikes that you drive into the earth and the post fit in the top.

Answer 6

get some roof tar and paint the posts bottoms  to above the  ground and then just put them in the ground. no need for concrete,,,waste of money ,effort and time.

Answer 7

Concrete is not required but recommended as it holds off the moisture from the post making them last longer and not rot below ground level.

however as long as the hole is deep enough about 18" in your case any solid packing material would give adequate strength

Answer 8

You can set posts in garden spikes.     The spike goes into the ground and the post goes inside the spike.         Good luck.

Answer 9

Since you do have high winds and snow, think of it this way. with gravel and sand , over time, and with normal land errosion , you'll be repacking the post time and time again. So yea , i would concrete them . Do it once and youll never have to worry about it again

Answer 10

You didn't ask but in addition to properly setting posts, properly gap your fence to allow some wind through.

Answer 11

If I were you I would install cassons

Dig your post holes about 2.5 feet deep, insert a concrete tube-- they are made of cardboard then back fill around the tube-- so you now have a perfectly round hole in the ground then fill it with concrete. Insert into the still sopping wet concrete a metal post holder. It will stick halfway into the concrete and the other half sticks up into the air, you attach the post to the part that sticks up. If you do it right it will be super stiff and the wind will have a hard time blowing your fence over.

The best part of the deal is when the fence post does eventually rot and needs replacing, all you have to do is unattach it from the metal and fasten in a new one. No concrete work is needed. The fastener can be used again and again, without any need for digging it up.

Answer 12

Always treat the ends of the poles with

ether a wood preservative or burn the ends

so they do not rot when in the ground.

dig hole deep enough to hold them

solidly.Others above explain different

methods of bracing your poles UK

Answer 13

Best to place all of them in concrete, we own Custom Concrete Structures here in Salt Lake and this is something our business does almost daily.  You can also have a small wall poured under the fence to make it look better

I wouldnt set a fence without it and I do not know why anyone would

Answer 14

Dig a hole and pack the post with large stones (you call them rocks - we save that word for larger items).  Push them down well with a heavy stick.  That will hold the post in place.  Filling the top with concrete is stronger, but you only need to do that at the ends or where you put a gate.

Answer 15

I live in Kansas and we can get some pretty good winters around here, and I know most everyone uses concrete for the posts, for the support of wind and snow blowing, but it also helps with preventing moisture from decaying to posts and also termite damage.

Answer 16

I just did mine ,and would really say yes dig 4 feet down and concrete all,I found over the coarse of time the 2 by fours between the post sometimes start to warp even pressure treated does also warp,And then the problems could start with a non concrete post going with it and causing more problems,If done the once the concrete way then you will save a lot of problems down the road.I would rather change some 1x6 boards than have to do a post and boards that are not really secured,Believe me in time your fence will become wobble and start shifting back and forth.Good luck on your project

Answer 17

Probably need to check with the city concerning your fence.  I'm sure there are codes that govern fence installs in Michigan (i.e. posts must be below the frost line).  And you might want to check to see if a permit must be pulled.  I'd hate to see you sink 40 posts and 300' of wood and be issued a stop order when a city official just happens to drive by your house.  Personally, I'd concrete every post.  It makes for a helluva job, but at least you know the fence won't fail...at least not the posts.

Answer 18

yes ,hawkeye, you do. If you want a fence to withstand wind, you must build it strong. You can't use the posts just to fill in the gap between the fence panels, they must be capable of supporting the fence in high wind. I advise you to concrete every post. You can buy, a rapid hardening concrete, in 28kg bags, and bag is enough to bed solid one post. It goes rock hard in 10 minutes or so. It won't fill the hole of course but you can finish off the backfill with . say gravel. I've built fences using this method, and I ve had no call-back.   If a job's worth doing it's worth doing well.  .

Answer 19

In UK we can buy 'postcrete'. You dig your hole, half fill with water, add the postcrete, refill with water. It sets in about 5 to 10 mins on a warm day, and cures properly very quickly. No mixing. No waiting to fix to the posts. I imagine your DIY stores must stock it.

Answer 20

Here in Scotland (with very high winds) we build fences like the first contributor said. No concrete is used, but they are whacked down VERY hard with a mallet.