Pole barn floor

[scotty95]

Had a pole barn built this week. Waiting a few weeks before the cement floor gets poored for weather to warm. Question is= I have good sandy soil. Asked all neighbors that have barns and garages if their floor sweats at all. Everyone says no sweating because of the sandy soil. Should I go ahead and put a vapor barrier down or not worry about it? I have never seen any water laying around in the 20 years Ive owned the property. Thanks for any input.

 

[Marctrees]

Vapor barrier should be under all interior slabs.

The sweating you talk about is in most cases a result of top surface condensation, NOT moisture infiltration.

So, poly under the slab does not affect that, but WILL reduce moisture infiltration from any soil water.

Even if you are high and dry.. The poly keeps the concrete water from leaching into the dirt ... leaving it where it needs to be... correctly and fully hydrating the slab curing process.

The same reason they cover or water curing concrete for a maximum fullness of hydration - in simple terms Slab strength.

Relize concrete does not dry, it cures.

Something like 85% of the water in concrete is chemically converted...

ONLY approx 10-15% or so water actually EVER leaves the concrete.

Marc

 

[Marctrees]

The reason the Neighbors are NOT sweating has nothing to do with being on sandy soil...

But because of your local weather.

If it is true neighbors are not sweating... it is only due to apparently you live in a low humidity are.... AND their cold glass of beer also sweats less then.

Marc

 

[Spook001]

I’ve got a garage that the floor is always damp, no vapor barrier. I put vapor barrier in my pole barn, it is dry as a bone. I’ve got very sandy soil. The moisture wicks up thru the concrete. Btw, I’m in Howell.

 

[Captain Spaulding]

I’ve got a garage that the floor is always damp, no vapor barrier. I put vapor barrier in my pole barn, it is dry as a bone. I’ve got very sandy soil. The moisture wicks up thru the concrete. Btw, I’m in Howell.

If the soil under your building is that wet, you have a drainage issue. I have pole buildings with dirt floors and both are absolutely bone dry year round. Dust is a problem, but never moisture.

 

[scotty95]

Thanks for replies. What type vapor barrier did you use? Looking into that.

 

[matt_i]

The poly keeps the concrete water from leaching into the dirt ... leaving it where it needs to be... correctly and fully hydrating the slab curing process.

The same reason they cover or water curing concrete for a maximum fullness of hydration - in simple terms Slab strength.

Agree for this reason....obtaining maximum concrete strength. As Marc states allowing the bleed water to go out of the bottom of the slab into the likely dry subgrade defeats all efforts put onto the top of the slab (wet curing, curing sealant) to "get what you pay for" in terms of max compressive strength.

6 mil is barely adequate, 10 mil is better.

 

[Marctrees]

"6 mil is barely adequate, 10 mil is better."

Good answer.

Either thickness would be ok IF undamaged... but the 10 mil rips and punctures less under their boots and shovels.

Marc

 

[Marctrees]

https://www.menards.com/main/paint/...51-c-8188.htm?tid=-8203006017699267861&ipos=2

Only damn thing is that 10 mil is almost 3x the $ of 6.

O well.

There are fancier films specifically made for under concrete, but all I have ever seen on small to mid even commercial jobs is either 6 or 10 polyethylene like the link.

And, really, it's gonna be 4 mil less'n YOU spec or supply different.

Marc