pole barn posts and concrete cracks

[air cooled]

Hey all,

I am in the planning stages of a Spring/Summer pole barn build.

While reading through the 'flooring' section I read a post by JOES169 where he said "As a concrete contractor, controlling cracks isn't just luck, but pure diligence. I have been using a "Soff-Cut" saw for 12+ years, and in Summer, I saw probably 80-90% of concrete the same day. I take extra steps isolating inside corners with soft felt to allow for shrinkage movement, we cure seal almost everything within an hour of finishing, and I carry a pair of slippers in my truck so I can get on a slab to saw as early as possible with out marring."

What caught my eye was his mention of soft felt in the inside corners.

As I understand it, my concrete floor will be poured to the outer edge of my posts (three sides of the post will be in concrete and the 'outside' edge of the post will be flush with the outer edge of the floor)

Is this the correct way to do this?
If so, putting felt along the three edges of the posts that touch the concrete sounds like a good idea.

Are there any other ideas for reducing the chance of cracks starting at the post 'corners'?

Should I cut relief cuts in a box pattern around each post to stop cracks from spreading?

Am I overthinking this?

Thanks

 

[machsnell]

If your pad touches 3 sides of the post then yes try and isolate.

Can the posts be your saw cuts on your control joints?

Sent from my SM-G900V using Tapatalk

 

[joes169]

Rather than felt, we generally rip sheets of "Tuff -R" foil faced foam insulation (4x8 sheets, 1/2" thick) to the desired depth. We ALWAYS wrap the 3 sides of the posts, as well as the treated "rat board" at the base of the shed. It's a very cheap thermal break, and it actually gives us a better finish at the edges by not having to search for a chalk line in the heat of a pour.

IMPO, wrapping posts is elemantary to concrete floor construction. The 90 degree corners, set at 8-10' intervals, are prime spots for re-entrant cracks to occur. It't pure laziness, or ignorance, to look over them. I highly recommend running control joints to the middle of the posts as well.

This logic goes beyond pole buildings as well, we literally wrap every foundation stem wall at the OH door and service door returns. Anything that can restrict the movement of the concrete slab as it shrinks can become a stress riser, and subsuquently, a random crack.

 

[air cooled]

Thanks guys

I will look into what to wrap the posts in (I don't know what "tuff-R" is but I will look it up).

I don't want a control joint at each post however, that would be 10 width wise and at least 2 lengthwise.
That's why I was wondering about cutting a control joint around each post.

I could cut a sonotube (or something like that) in half and put that against each post.
That way the concrete would be rounded around each post and have fewer 90 degree angles?

 

[SunsetsAndFriends]

Thanks guys

I will look into what to wrap the posts in (I don't know what "tuff-R" is but I will look it up).

I don't want a control joint at each post however, that would be 10 width wise and at least 2 lengthwise.
That's why I was wondering about cutting a control joint around each post.

I could cut a sonotube (or something like that) in half and put that against each post.
That way the concrete would be rounded around each post and have fewer 90 degree angles?

I recommend looking very carefully at putting in all the proper joints to control cracking. If you do not put in all the needed joints, there is a good chance for unsightly cracks cutting across the floor. Keep in mind that you can use something like Sikaflex to fill the control joints.

My 2 cents. Free.

 

[astroracer]

I think you over thinking it. The concrete will crack, you aren't going to stop it. Substrate prep is more important then wrapping a post. The concrete will shrink back during the curing process. Spend a bit more on a better base, go 5" + with a reinforcing mesh and make sure the footings and slab are well drained to prevent frost heaves. That's about all you can do.
Mark