New concrete question

[famous187]

I had a new 30x50x12 pole barn constructed a little over a week ago and the concrete was poured 12/29. It is 4" thick and has a vapor barrier. The walls and ceiling are insulated in 3/4" Thermal 3-HT RRE and the door is insulated as well. The building has been pretty much kept closed up since the concrete was poured. The weather over the last few days has been highs of 30-50 and lows of 15-30, and some rain here and there. Today it is currently 42 (supposed to hit 60) and pouring rain. I went into the barn this morning and the majority of the concrete floor has a thin layer of moisture and some of it is dry. Is this something I am going to be constantly dealing with or is this due to the new concrete? thanks

 

[LegacyIndustrial]

The concrete will push moisture for 30 days at least. However, I am not sure you are supposed to be seeing it collecting on the surface. This may be a floor that is colder than the rising air temp causing some "dew" to occur.

 

[dfiler2]

New concrete will heat as it cures, I'm guessing the right weather conditions have caused condensation.

 

[raffaelli]

Did you add an admix for the cold temp pour?

 

[starquestMM]

If the building has been closed up since the pour, its probably pretty humid inside. That's good for curing the concrete, but might make it more likely to condensate like that.

My house's garage will do it sometimes in the spring when the ground is still cold and a warm/rainy front comes through with a lot of humidity.

mm

 

[famous187]

Thanks for the replies. I have opened the door now and I guess I will just see how it goes over the next couple days.

Did you add an admix for the cold temp pour?

I do not know, it was done professionally.

 

[Bondo]

Thanks for the replies. I have opened the door now and I guess I will just see how it goes over the next couple days.





I do not know, it was done professionally.

Ayuh,.... Concrete takes 'bout 28 days to cure, it don't dry like paint,....

Close the doors, 'n keep it's heat, 'n moisture relatively high,...

Don't worry 'bout the condensation, til yer movin' in, 'n heatin' the place,...

 

[Jlbc212]

I covered my with plastic for a month to keep the concrete surface damp.

 

[famous187]

so its been about 16 days since the concrete was poured and it still has some moisture over much of it. is there anything i can do right now that would dry it out so i can get some work done in there? the floor is very slick when its wet.

 

[DC73]

so its been about 16 days since the concrete was poured and it still has some moisture over much of it. is there anything i can do right now that would dry it out so i can get some work done in there? the floor is very slick when its wet.

Don't rush the cure. You want the concrete to set up as strong as possible. Give it 30 days at least.

DC

 

[benwah]

Pretty much every spec-book will have a section in it for concrete and curing. Almost everyone agrees concrete must cure a minimum of 28 days @ 75 degrees Fahrenheit. At colder temps it most definitely will take longer. If it was my new garage, I wouldn't mess with it until at least 28 days, if not more, being that you have temps below freezing for extended periods of time.

 

[Angelfire]

You are somewhat fortunate that it's staying wet for so long. Oftentimes, the water evaporates off quickly (ie. warmer temps/summer).....you want it wet for as long as you can so just leave it alone. You are getting a good cure and it will make for a much better floor.

 

[famous187]

So we have had very cold weather and quite a bit of snow for the last couple weeks. The floor had dried out completely during that time and turned a white chalky color. The last couple days have been really nice, reaching 60 degrees, and once again most of the floor is fairly wet. It is not coming from above, no leaks. I'm assuming the concrete floor is very cold when the temperature is cold outside and when we have a large and fast temp swing the floor sweats because it is colder than the air in the building. What can I do about this?

 

[LegacyIndustrial]

A fan will solve this pretty good. Air movement reduces moisture.

 

[famous187]

ok i have two 50" overhead fans. just keep them running on a slow speed i guess?

 

[LegacyIndustrial]

Correct. The moisture will evaporate. Once the delta has reduced (slab temp rises) you will be in good shape.

 

[eljay]

I'm having the same issue as famous187, so I'll add it on here.
New construction and concrete walls were poured back in November. Just this past week I noticed dampness accumulation on top of the foundation wall only in one corner of the garage. The garage is unheated and the house is still under construction, so there's only temp heater in the house that contractors were using to heat the house for the last 3 weeks or so. The rest of the garage slab and foundation walls are dry. The builder even opened up the wall over that spot to confirm that there's no leak.
They said it's just dampness coming out of the concrete and that it will likely happen every winter since the garage is unheated. I find that hard to accept in a new construction.
The wall in that spot/corner is completely dry on the outside, so it seems to seeping out from the center of the wall to the inside.
It's been wet/damp in that spot for at least 3-4 days despite any other splash of water on the garage slab drying out within 20-30 mins.
Is that normal or should I be looking to get an engineer to address this?

Thanks.

 

[PT Doc]

I'm having the same issue as famous187, so I'll add it on here.
New construction and concrete walls were poured back in November. Just this past week I noticed dampness accumulation on top of the foundation wall only in one corner of the garage. The garage is unheated and the house is still under construction, so there's only temp heater in the house that contractors were using to heat the house for the last 3 weeks or so. The rest of the garage slab and foundation walls are dry. The builder even opened up the wall over that spot to confirm that there's no leak.
They said it's just dampness coming out of the concrete and that it will likely happen every winter since the garage is unheated. I find that hard to accept in a new construction.
The wall in that spot/corner is completely dry on the outside, so it seems to seeping out from the center of the wall to the inside.
It's been wet/damp in that spot for at least 3-4 days despite any other splash of water on the garage slab drying out within 20-30 mins.
Is that normal or should I be looking to get an engineer to address this?

Thanks.

Sounds odd. Moisture evaporates. If you spilled a lot of water on the floor it would evaporate within days unless there is 100% humidity. There must be a source for something to stay constantly wet or damp.

 

[Dick in Wisconsin]

Mr. Eljay: Is the contractor using a propane heater in the house/garage to heat the building while under construction? If so, those put out lots of moisture which is probably condensing on a cold spot on the concrete.