Fencing question

[bunyip]

We need to replace a short section (about 100') of boundary fence using 5 or 6" treated pine posts and I have seen foam used to secure them into the ground.
My questions are:
1. Is expanding foam as good as the makers claim.
2. What sort of space do I need between the post and soil, I have an 8" auger on my post hole digger which would only leave a 1" space, is this enough or would I need more (or 1.5" gap on a 5" post).
3. Would I be better off just using quick set concrete mix.
4. What are the differences between a 5 and 6" post.

I am looking at the fastest but don't want to compromise on strength, normally I would use a contractor but as there are a lot of trees on the boundary he cannot get his tractor in and would have to hire a dingo, my BX2370 will fit in and will save me the dingo hire fee.
This is going to be a wire fence with a sight wire on top, I can wire myself, the corner posts are in good condition and I can use these again.

 

[Diggin It]

First question .... if it's a wire fence, why use wooden posts instead of metal T-posts?

 

[bunyip]

Because that is all people use here, not familiar with metal T posts.

Edit. Did a quick google, that is what we call star pickets, not strong enough to hold livestock back, horses will bend them over getting to grass on the other side.

 

[Diggin It]

OK, well the only thing I've ever used for a wooden post is concrete. Not familiar with any foam product for that use.

 

[bunyip]

This Self-Expanding Foam Lets You Set Up Fence Posts In No Time - YouTube

There are others.

 

[jaxs]

I've lived around cattle and horses more than 70 years and never heard of setting post in foam. Steel T-post restrain's horses and cattle all over Texas. Unless something is bad wrong with the T-posts,you need to feed your horses if they break post getting to grass. 90% of wood posts around here are driven into ground with a tractor or hand tamped when set in holes.

 

[Diggin It]

^^ Yeah, cattle, horse, goats, everything here is behind T-Posts. The only place wood is used is for corners and gates and those are often old utility poles cut in sections.

 

[bunyip]

I just saw the idea and thought I would ask the question, they are well fed but as they say, the grass is greener on the other side, they also have their own water troughs but reach over the fence for the neighbours cattle troughs.
Posts are driven but as I stated tractor cannot get into this spot but I can with mine, traditionally metal posts are only used inside boundaries and often as temporary fencing, we can get boggy and metal posts will lean over with little pressure even though driven deep, wooden posts will resist this with the greater surface area.
The appeal was the two minute set time which means we can wire up quicker and have a secure fence in a couple of hours.

 

[oosik]

Around here very few horses. This is cattle & wheat country. I've never seen cattle behind wooden posts. Wood is used so horses won't hurt themselves on the metal T-post. T-133 metal post is the almost universal choice for cattle fencing along with four strands of barbed wire.

In rare instances ranchers still ride horses to manage cattle. The modern rancher is on his ATV as he moves his cattle.

Like you indicate - foam would allow rapid set up. 100 feet - what is that - seven/eight posts. I'd give it a try. The foam will grip the soil as well as concrete - question is - - is the foam rigid enough to resist toppling under pressure.

 

[Diggin It]

The appeal was the two minute set time which means we can wire up quicker and have a secure fence in a couple of hours.

When I set a wood post, I pour the concrete mix in dry, wiggle the post a bit then check it for plumb, tamp the dry concrete mix down, then tamp dirt on top. Moisture in the ground leaches into the concrete mix and sets it. If it's been overly dry, I'll pour water around the post after setting it. The dry, tamped concrete is usually firm enough to hang wooden fence panels right away.

 

[TheMan419]

We did exactly what diggin said. Wired fence same day. Hung 12 foot gate same day. Just made sure end of gate was supported for a couple days for concrete to cure.

We are clay soil so only corners and gates are wood. Rest are t posts.

 

[jaxs]

How much time is there to be saved building 100 feet of fence?

 

[kenmac]

except for 6x6x8' corner post the rest ate T post. Now if I'm pulling barbed wire for a long way. I will install a few 4x4x8' post along the way

 

[bunyip]

100 feet - what is that - seven/eight posts.

Standard spacing is 2.4m which is about 9' plus we have trees where posts should be so I'm working on about 12 at about $9 each for 6' posts (I'm getting better at imperial measures).
2' should be enough to hold them in, I should add that the foam I saw was a US idea not one that we have initiated.
That spacing will allow rails later if we want to go down that track, the boundary is the front of the place and it would look nicer (according to SWMBO who just oversees the project, I finance thbem and get to do the labour).

 

[Streetcar]

What is the strength of the foam for fences. On road work there are different formulations

 

[jfh28]

This Self-Expanding Foam Lets You Set Up Fence Posts In No Time - YouTube

There are others.

that is incredibly interesting.......never seen that before......I'd probably have to use it once to render an opinion on it.......concept is sound if the foam will not break down with the reaction of the soil make up you have or ground water you get.......I would think how well your particular soil compacts would effect how well it would do in terms of lateral forces applied to the post.....I'm thinking sandy soils not to well while rocky or well compacted would do fine.......and I certainly like the idea of light little bags as opposed to lifting 50lb+ concrete bags all day long........do you know how much a bag of it goes for?.......thanks Jack

 

[HickoryFarms]

We use foam for setting our poles at the utility i work for. Works great. Only problem is getting rid of the dirt. But I’ve set 100+ foot poles with foam. Our original stuff didn’t work in water, meaning, it sit on top of the water, the water would recede, and leave a void. Our new stuff with push the water up, and out.

 

[bcp]

About $12 for 100lb concrete equivalent.

https://www.homedepot.com/p/Sika-33-fl-oz-Fence-Post-Mix-483503/205671519

Bruce

 

[Wagtail]

About $12 for 100lb concrete equivalent.

https://www.homedepot.com/p/Sika-33-fl-oz-Fence-Post-Mix-483503/205671519

Bruce

... & Bunyip. This is a bloody interesting product. The only foam I've ever used is to plug a 'household' hole.

How did you hear about it? Research or a conversation?

 

[TractorGuy]

I have heard that T-Post won't work well in soft or boggy ground. I did a short 100 ft section a while back and used the larger 7"-8" posts every 30 feet with two T-Posts in between. The main reason I used the larger wood posts is they were on corners and gates.

I set my wood post with concrete and just put it in the hole dry and tamp as others have suggested. It's ready for wire as soon as it is tamped. Water will seep into the concrete and set it as time goes on.