Hello. I'm a newb to this site and have little hardwood flooring experience.

Background (best I can). The wife and I bought a new home in Columbia, SC in February. We are on an elevated concrete slab, probably a foot over ground level in the back yard, and 2 feet around the sides and front yard. The bamboo that was installed was a heavier version than what you typically find. It was glued to the slab with an adhesive. It's now cupping. The builder came out and told me that it was due to the change in temperature within the slab (we are having a hot summer after the floors were installed during the winter). I have no idea exactly what kind of glue was used. All the information I can gather through goole searches seem to indicate that floors cup becuase of moisture. We are within our 1 year full warranty period.

My question is what should I do? Does it sound like there's moisture? We have a 3.5 month old daughter. Will the moisture (if it's there) be a potential hazzard to her, and can I tell strictly from the cupping bamboo? It would be a major pain to have the whole thing ripped out and re-done. But if it comes to that, what should we do to make sure this doesn't happen again.

Thanks in advance.

well if its under warranty and the floors are cupped to the point they wont flatten back out. i would have em tear it out and replace it. It could be a bunch of different things and probably is a combination of all the factors you already have mentioned. SHort story it sounds like the floor was installed incorrectly and he should fix it. probally need to get a few estimates on replacement and ask the new guy whats he going to do so it doesnt do it again.

But floors also exhbit dry cupping as well as wet cupping. Get a qualified inspector out there. Make sure he has installation background experience, I mean lots of it not some carpet cleaner or carpet salesman gone inspector.

Also, it is natural for floor to cup somewhat. It is not a total bad thing, just natural in some respects. It's wood!

Id be willing to bet dry cupping in SC is pretty limited but there again you never know . Anyway, the subfloor needs to be tested, the flooring needs to aclimate and the home needs to keep a fairly constant r/h.

Just to add to what has been mentioned, cupping is usually an indication that moisture is under the wood, in this case coming up through your slab and is trying to escape up into your house where I imagine you are running air conditioning.

If this is the case, there is a chance that in the winter time, the cupping will subside and the flooring may return to flat. Then again, it might not . The home should be checked with a RH meter and the sub floor and flooring should be checked with a moisture meter as mentioned.

Regarding installation, a pro contractor will always test the slab and the flooring prior to install. Also, there are great products on the market that can be applied to your slab to help block / block moisture transmission.Hopefully he used one of the available products. Sika and Bostich are two of the companies that make quality flooring adhesives and related products.

Lastly, I just installed a 4 inch oak floor on a home near the water. I did everything I could to acclimate it but I knew it would cup and warned the homeowners that it would. Once they turned on air conditioning, the floor started cupping. Once they turn it off and the basement starts drying out in the fall, the cupping will subside. I hope this helps explain your situation a little better.

As Paul mentioned the bottom of the wood has a higher moisture content than the top which makes wood cup. The AC is most likely the culprit here but hard to tell.

What is the relative humidity right now? If it is very low you can try a humidifier which will help.

www.wunderground.com indicates the average temp of 71 degrees 61% humidity, during this time frame, which certainly could cause cupping unless you have a dehumidifier to keep prevent it. Get a hygrometer and see what your humidity levels are in the house. Also have someone, the installer should have one, to take a reading with a pin moisture meter if the reading is above 12% that is most likely too high but in your area a little higher could be ok. NWFA guidelines state if the subfloor or hardwood read higher than 12% do not proceed with the installation until humidification or de-humidification gets the humidity levels between 35% to 55%. Most mfg warranties state this in their warranties and they will do nothing if it is outside this range. In El Paso it is so dry we seldom experience this but cupping, due to high levels of humidity, can occur in high humidity areas. You need to have whoever did this job for you provide the manufacturer's instruction guidelines, warranty info and maintenance instructions then you will know what is expected. As to mold and mildew or rot that starts to occur at 22% moisture content so as long as it is at a level less than that it should not be a concern. If your installer doesn't have a moisture meter go to www.nwfacp.org and find an inspector or consultant to evaluate your situation and determine the cause.

Thanks for the replies everyone.

From what I gather, it's a matter of the slab having moisture, and that moisture is drawn out by the air conditioning. It's very hot and humid now.

I believe my next question would be: will bamboo flors cup in my house even if re-installed properly? I'm not sure there's any way to keep moisture from entering the slab. The reason I say that is because we are surrounded by red clay. That red clay will hold moisture for a very long time. Even with a moisure barrier on the bottom of the slab, I imagine moisture can seep in through the sides.

I'll keep the 22% RH percentage in mind regarding mold and mildew. That is certainly my primary concern. Of course, I want a nice looking floor too. I have a feeling it's going to be a fight to get someone to come fix this problem.

There's a HUGE difference between 22% moisture content of the wood vs 22% rh. Apples and oranges.

As for the adhesive, some newer adhesives can be waterproof when cured, some are not. Best bet was to use a trowel on moisture barrier like Bostik MVP4 or similar. Even though the moisture levels in the slab were OK at time of install, they can elevate to the point the vapor penetrates the adhesive to much causing cupping ie bottom wetter than the top. Add then the drier conditioned air you will get cupping.