New carbonized bamboo flooring (Ecofusion/click n lock) professionally floated and installed in July/2013 over an 18 year old concrete above ground slab with Lexfloor vapor barrier - no moisture testing done prior to install. Live in northern CA and have experienced a very mild winter to date and there is no known water or landscaping issues. Now, after 5 months, floor is beginning to cup in areas. Installer has agreed to replace those problem areas but at this point it doesn't make any sense to replace anything without any kind of moisture testing. If moisture test is high, would sealing the concrete, prior to installing the vapor barrier help, or, if moisture readings are high maybe a floating floor is not in the cards - thanks for any input!

Sealing helps but does not prevent.

there is obviously a moisture imbalance as that is what causes cupping.


if its from the slab or the materials environment themselves needs to be determined.

floating is the best alternative in my opinion .there is no break in retarders.

testing is always recommended.

I agree that replacing effected areas with new without knowing what the issue is seems foolish.

I suspect it maybe a material issue and not your slab but testing would reveal that.
a meter that reads Bamboo is needed. are the materials engineered?
an average dry slab would be below 4.5 % as a general rule of thumb.

having meters that read deeper then 1 inch help as they can tell you what's goin on deeper but at very least meters that read 3/4" should suffice

If it's floating and over a proper underlay then somethings up. If it were real wood I could tell you more but that bamboo is a crap shot. It's unusual for a floater to cup. Not being bound to the subfloor allows the floor to shirk and expand freely reducing the effects of a moisture imbalance. I would do some investigating with a proper moisture meter to see if you can locate the source of the problem. Is the whole floor cupped? If not are the areas cupped close to a water line,icemaker, toilet supply line ect? I would be willing to bet you have a small leak some where. Floating floor are the best for high moisture situations so to see them cup is unusual. Id contact the manufacture and have a them send a rep out to look at it the problem. What the r/h of the house currently?

Problem with most bamboo is it's moisture content in arid zones as it comes in to wet from where ever it is manufactured. Many places in California are arid zones like mine here in the desert. Bamboo can lose and gain moisture faster than a real hardwood unless it is stranded which takes much more time. "Professionally installed" does not mean it was correctly installed. You have three options when installing bamboo;

1) Unpack it and dry it down to the median seasonal level for your zone. That can be difficult to achieve and in my experience can cause deformation, delamination and checking of the planks if you go to low. Winter is a dry season and many wood floors experience "dry cupping" which might just be your problem.

2) Get a humidifier and keep the rh level in your home to match the moisture content of the flooring as it came out of the box. This is mostly not achieveable in arid zones, but not in high moisture zones of the country.

3) Don't unwrap it and just install it right out of the box and cross your fingers.

Moisture imbalance; "Wood’s equilibrium moisture content (EMC) is influenced by the relative humidity (RH) and temperature of the surrounding air. Wood will lose or gain moisture until it is in balance with this surrounding environment."

http://www.wagnermeters.com/flooring/wo ... installed/

If this is strand bamboo then understanding cupping may be easier than you think. Strand bamboo is extremely dense and because it is, moisture moves very slowly though it. i.e. acclimation time is extremely slow. Moisture meters do not work on strand bamboo so you can never really tell when they are adequately acclimated. When you replace planks that are cupped do so using planks that have been acclimated for 30 days! I know that sounds like a lot but take the planks and elevate them off the floor a few inches in stacks of not more than 5 or 6 high and allow air to circulate all around them in the room/home where you are going to install them. Let them sit for 30 days and you will not have any more cupped floors once they get installed unless there is a moisture problem from below. If you do not adquately acclimate, they will cup again.

Check the humidity levels.
Calculate dew point.

There may be more going on here.
Overlapped & Sealed moisture barrier?