Expandable Foam for setting posts

Has anyone ever had any experience with using foam to set a posts verses using concrete?

Why?

Need pros and cons and would you advise using the foam verses concrete?

I wouldn't think it would last to long. it would absorb water then freeze

I haven't and I wouldn't. Carpenter ants love that stuff .

What are you setting it in ?
What are you using it for?

I saw a commercial for some foam that was made for setting posts, but I can't remember what it was called. Looked pretty interesting

I saw they used it on telephone pole here in ND. So I would think it must work.

I used it once for setting a satellite antenna post.
It was simple to use and held the post ok but I don't think it lasted long. The guy I set it for sold the house so I didn't have any follow up.
Oh yeah . I used it again setting a clothes post for Mom but Dad didn't like it and tore it out.
just.

you tube it,I watched a review,it filled up the hole,but later shrank and got loose,didn't seem to work well at all.

watched my brother in law use it on a couple of fence posts. didn't impress me none. especially for what it cost.

Not for exterior use, generally. Not without a vapor barrier or something to keep the subterranean vermin from intrusion.

"Expanding foam" is a generic term. I assume you don't mean the crap in a can, obviously that won't work. The two part urethane won't work either, it'll break down in no time. There MAY be something out there used in the industry, but whether you can obtain some or not is another matter. I've never seen it, but maybe I never looked hard enough. But I can't think of any advantage a foam would have over concrete.

Not just ND, I've seen it used by power companies all over the place.

To answer one of the questions >>> setting 4x4x8 wood, for sings, on a volunteer project we are doing.

Yes, I have known that power companies use a expandable foam product as a backfill in issue spots. They support poles 35 foot and higher poles with the stuff.
I just don't know their success or cons have been with using it.

As you are using it for public use better stay with a tried and true method
There probably is a product used but is only economical in large quantities and saves on labor

Sand quicker, cheaper, and set tighter

I can't speak for all soil types, but using sand around here just leads to failed posts and more work later pulling them out and doing it right. I've tried it all looking for an easier way, sand, stone, pea gravel. But back fill and tamp or concrete are the only ways that last here.
What's the aversion to just using a sack of concrete?

I used it on a gate post in my yard 2years ago and have had no troubles so far. Stuff I bought was in a sealed rwo part sack and you break the seal between the two sides and mix them together before opening sack and poring in hole. Worked real slick and was cheaper then a sack of post cement.
Power line guys and Hwy dept have both been using for several years and guys I talked to highly recommend the stuff.

It's called pole krete. Used for utility poles. It works really well.

More videos at- https://www.youtube.com/results?search_query=polecrete

^ thanks for that clip and thanks for all your advise and knowledge. It will be an option for us to consider using in the next few weeks.

Have you thought about using chat. I've used that instead dirt in some wet areas where I had to build fence.

It's my understanding, because of todays pressure treated lumber, you shouldn't ever use concrete to set a post. The process of pressure treatment and the chemicals used are inferior to the old method. A modern pressure treated post will rot out in short order when set in concrete. A 3 foot hole with a paver at the bottom, put the post in, some rock around it tamped tight and backfill with dirt.

We use a 2 part foam on the railroad to plug ties when gauging track or changing out steel and steel gang uses it to lay 1000ft to 3000 ft. A day.

That’s not correct. Pressure treated wood is set in concrete all the time. You do need to use different types of fasteners with a certain type of PT wood.