Condensation after concrete

[Jslys13]

Hello I have a 32x40 pole barn built earlier this year. Metal siding and shingled roof. Last Friday I had the floor poured. Now I'm getting condensation off the roof dripping down on the concrete. Also had condensation on inside of wall the first few days but that has stopped. Is this just from the curing concrete ? Never had this problem until the floor was done. It has been in the 20s at night and 40-50 during the day.

 

[6768rogues]

Yes.

 

[matt_i]

Hopefully you are moist-curing the floor to build strength if you didn't apply a curing sealer....

 

[Showkey]

That new concrete is going to give off water for weeks. So that is a special case until it’s fully cured.

That said sweating and condensation is a common issue with metal building and other storage structures. Heat and cooling and the weather will vary and the sweating may come back under certain conditions even years after the concrete pour. Concrete is not the problem as dirt or gravel floors have their own issues.

There are dozens of posts on the topic.......metal structures and materials used , insulation, heating cooling and the weather have a part:

https://www.garagejournal.com/forum/showthread.php?t=374197

 

[Jlbc212]

Every time I have a concrete floor installed I cover the entire floor with 4 mil plastic for an entire month. That might help reduce the condensation you see on the underside of the roof.

 

[rburke65]

I had my pole barn floor placed late in the year...Oct.....Nov. opened building per sat....no insulation. Right or wrong.....don't care it was 40 years ago......we sprayed Thomson Water Seal on it, covered with plastic and put straw atop the plastic to keep in the heat. Worked well. Floor is like....concrete! Ha. And yes the condensation is from the curing.

 

[DCarr2]

when I poured the floor in my 1650' sq ft shop last spring, it literally rained for a week...

I took this opertunity to mist the floor and keep it wet for 2 weeks... to help with strength...

when I say it rained, you couldnt walk in there with out getting really wet!

your contractor should have mentioned this.

 

[wssix99]

Is this just from the curing concrete ?

No.

Never had this problem until the floor was done. It has been in the 20s at night and 40-50 during the day.

It's curing concrete + weather + (I'm guessing) a non-insulated ceiling

The curing concrete will make the air inside humid, and a little warm. When that (relatively) warm humid air hits a cold ceiling (like when it hits the 20's at night), mother nature turns that humid air in to rain. (but inside the building)

The fix would be to fix one of those variables:
- Ventilate the humid air out
- Run a dehumidifier
- Heat the ceiling
- Insulate the ceiling
- Stop winter from happening

 

[Jslys13]

Would it be best to leave the garage doors open

 

[wssix99]

That should help. Their arrangement will dictate if that will provide enough protection against freezing.

Another thing you could do is put plastic down on the slab. That might keep the moisture out of the air. You'd get condensation, but it would stay on the plastic and slab.