Please help! I live in a 6 y.o. condo w/ gypcrete floors on the second level of the house - which is over a garage. I wanted to install wood floor but the gypcrete was very unlevel across the floor. We ended up having a company do a gypsum pour across the entire leve 450 sq ft. about 5 weeks ago and the floor is completely level. I am concerned about moisture though. I did a calcium chloride test and it came back w/ a reading of 8 lb/1000 sq ft. What does that mean in terms of percentage moisture in the floor?

Is it possible the floor is still too wet? I will be floating a 5/16" wood w/ a 3 in 1 padding. I am concerned that if I put the floor down it will get damaged from the moisture or that even worse it will mold. The temp and RH in the house have been extremely consistent in the house at about 73 degrees and 50%. I need advice on whether to wait to lay the floor and how to get this floor dryer.

If you did the test correctly and that is the reading, then the substrate is too wet to lay a wood floor over. An acceptable reading for an engineered floor is approx. 3 lbs. per 1000 ft. in a 24 hour period. I suggest doing another test or use a moisture meter to verify that you are performing the CC test correctly.

Thanks for the quick response. I was concerned about the test as well so I did it again in a different spot with similar results.
Does anyone know how long it typically takes for gypsum to dry to an acceptible level? The installer indicated it would take just a few weeks and gave me a sealer to put on it - and I did that already.

Also, do I need to remove the sealer to accelerate the drying of the floor?

How many CC tests did you set at one time?

The area is about 500 sq ft. I did one test at one side of the room. After 60 hours it came out to be about 9 lbs/1000 sq ft. I thought that seemed so high so I did another one on a different side of the room.

For it to be ASTM 1869 protocol there must be three set.

Right, I understand that and I still have one test left. I did 2 and they were so high that I didn't do the 3rd one yet. I thought maybe the floor needed more time to dry and I would buy/run another series of these tests again after some more time.

I guess my issue/concern is that I thought the gypsum would be dry by now. It's been almost 6 weeks. I am not sure if it's because my condo is over a garage and that it's warm and humid here in NJ and that's causing the gypsum to dry slower.

I have the wood already and I'm so upset that this floor is still wet because it's so disrupting to live with no floor in and furniture in my kitchen! I am at my wits end I am not sure what to do to help the process along. I have the AC running at about 73 degrees and I bought a hygrometer which says the humidity has been a constant of about 50%. It's too hot outside to open the windows and it may not help anyway b/c it's humid outside.

I want to do this right so I am trying to be patient. I am pretty worried that I was stupid to put on this sealer that the gypsum installer gave me and that I'm now trapping moisture in. I didn't really take the time to ask exactly what it was.

Well, this MAY be the problem. If you cannot wait any longer, you MAY be able to proceed by laying an 8 mil polyethylene vapor barrier over the whole thing. Over lap any seams by 12" and tape them securely with duct tape. Lap the poly up the walls about four inches. Then float your floors with the pad. After the install is done, then install the baseboards and trim back the poly film to the tops of the base. This should work. I've laid floaters over some pretty damp conditions and as long as I put down a thick, continuios poly film ( and did not poke holes in it), it kept the floor from absorbing the moisture.

Thanks for the reply. Would there be an issue with moisture between the substrate and the vapor barrier causing mold underneath the floor?

I'm absolutely terrified of creating mold in this house - even though I have no honest idea of how much moisture is necessary to create mold underneath a 5/16" engineered floating floor! Is 8-9 lbs/1000 sq ft. enough to cause that type of problem?

Finally, am I slowing the drying by running the air conditioning too much?!

Thanks so much for the feedback. This is keeping me up at night. I can wait longer if that is what it takes to make sure 1) I don't make everyone in here sick from mold and 2) I don't waste my money by ruining a wood floor due to moisture just from being impatient.

Eureka I've found it. FYI.
I contacted manufacturer of gypsum that was poured and was told that calcium chloride test is not appropriate for gypsum since MV can be absorbed from air around the test dome and give a false reading.

They recommend the plastic sheet method or measure w/ a Delmhorst BD-2100 or G-79. Generally after 7-10 days poured gypsum up to 1" should be dry under what they call optimal environmental conditions.
Basically there's a good chance I've been losing sleep over something that is most likely not a problem after all - I just needed to perform different tests. Oh well, better safe then sorry! Thanks for all the input.

Yup. There is no such thing as a "proper" CaCl test over gyp. I would use an encounter meter. I am sure the ones you listed are that type.

Yep, use a Tramex concrete moisture meter.

The sealer will make a cc test and a moisture meter freak out, too.