polyurethene fence post mix?

[2manyrocks]

Has anyone used the Sika Fence post mix to set a fence post, deck post, anything like that? $12 for a bag that is supposed to replace two 50lb bags of cement. Sets quickly, lighter weight, relatively easy mixing, but how well does it hold a post compared to concrete and does it absorb water that will rot the post?

 

[EddieWalker]

Never tried it, but I know that there have been a lot of new and creative ways to use foam that sometimes works, sometimes, it doesn't. I'm sticking with concrete, but look forward to seeing what others have to say about it.

Amazon has a few negative reviews that you might find interesting.

Amazon.com: Customer reviews: Sika 48353 33 oz Fix Fence Post Mix

 

[wagne223]

Using concrete to set posts does 2 main things.
1. Provides a larger solid surface for the surrounding soil to resist lateral and downward movement.

2. Provides weight which helps resist lateral and upward movement.

The foam will only do #1

So if you have good solid soil, no uplift forces and a light duty application, the foam may work.

In cases of loose soil, wind, and posts that will see varying forces such as a wire fence that animals will climb, press on or lift, or solid fencing like privacy fence, then I would stick with concrete.

 

[Diggin It]

Has anyone used the Sika Fence post mix to set a fence post, deck post, anything like that? $12 for a bag that is supposed to replace two 50lb bags of cement. Sets quickly, lighter weight, relatively easy mixing, ...

I usually get 50lb bags for around $2, sometimes less. How much easier can it be to add water and stir?

Why would I pay so much more for something that weighs less and may not hold a post down as well? Also, concrete is made of natural elements so I'm not adding chemicals to the ground which may (or may not) affect nearby plants.

 

[ArlyA]

Concrete is been around a long time, like 3500 years. Its a great product that been improved on many, many, times over the years and hard to beat. Personally I like "tried and tested" over new.

Concrete - Wikipedia

 

[TractorGuy]

I am with the others. I wouldn't choose foam over concrete.

Our soil is pretty dense clay/sand mix. The only time I even used concrete was on my gate posts. Even then I just tamped the dry concrete as I would when I fill any hole with dirt. I figure it will absorb enough water from the rain and soil to set. I can't tell any difference in sturdiness between the gate posts and other posts as far as pushing on them by hand. They both seem solid as a rock.

My dual 10' gates have remained perfectly level and aligned.

 

[RNeumann]

This is new enough that their aren’t many consumer level reviews. The claimed advantage over concrete is that it seals the post from rot. Concrete, on the other hand, is a sponge.

 

[2manyrocks]

At $12 a bag, my guess it will be used more by casual homeowners wanting to set a mailbox or something like that that don't want to mess with the weight of concrete.

If you had to hand carry something to set a post somewhere remote on a farm or ranch, it might be something to consider although tamping dirt seems to be the long standing solution.

 

[QRTRHRS]

I am with the others. I wouldn't choose foam over concrete.

Our soil is pretty dense clay/sand mix. The only time I even used concrete was on my gate posts. Even then I just tamped the dry concrete as I would when I fill any hole with dirt. I figure it will absorb enough water from the rain and soil to set. I can't tell any difference in sturdiness between the gate posts and other posts as far as pushing on them by hand. They both seem solid as a rock.

My dual 10' gates have remained perfectly level and aligned.

I second the dry bag for setting posts. I poke it with a 1/4 inch piece of rebar until it has settled out then start slowly back filling and tamping. If it is a gate post, I allow some time before I let the full weight of the gate hang, especially if I am not setting up an "H" brace. I would venture to say that premature post failure from rot is more likely due to poor quality posts, perhaps from minimal chemical retention such as from a .40 post. I am lucky enough to be able to still get CCA treated posts for agricultural duty.

 

[ddbackhoe]

At $12 a bag, my guess it will be used more by casual homeowners wanting to set a mailbox or something like that that don't want to mess with the weight of concrete.

If you had to hand carry something to set a post somewhere remote on a farm or ranch, it might be something to consider although tamping dirt seems to be the long standing solution.

I just used some to reset some rotten 4" line posts and one 6" gate post, our soil is mostly red clay. Per the directions from Sika, one bag per post but they don't seem to allow for hole and post calcs. One bag was plenty for two lines (4" post, 9" auger) and under one for (6 and 12). This is a maximum expansion mix and was pretty good for my application. No long term review because I just did them last month.

I opted to try this method because I was being lazy. Pulling and resetting concrete is a pain, if (when) these break off I fully expect to just run the auger through and add another post.