I had new hardwoods installed in my living room approximately 8 months ago. They were glue downs to a concrete slab. It appears they are now cupping. I had the installer come out and look and they said that the warranty does not cover it. He just told me that I need to make sure that moisture is sealed from the outside. However, I had my handyman come over and he said that it is probably not the case since the hardwoods are raised above the ground from where the water goes outside. I'm trying to find out if the installer should be responsible for the cupping or is it my problem to fix. What is weird is that there are hardwoods in the kitchen and the dining room that were installed by the previous owner on the concrete slab and there doesn't appear to be any cupping there (they are probably 10 years old).

Also, the installer checked the moisture above the wood and said that it was normal. So, do you know who should be responsible for fixing?

Solid wood over concrete is a very bad Idea, as your seeing. This may be a case, you have let the humidity get too high inside the installation area.

More likely, the old installation with no concerns, is an engineered cross-ply floor and not a solid wood.

The solid wood should have a moisture blocker applied a day or two before the adhesive is spread. (Most adhesive manufacturers, have a system, combination of blocker & adhesive, that are compatible.

Does the engineered cross-ply hardwood look like a few layers of plywood and then a hardwood on top? If so, this is what they installed. They matched it perfectly with the old hardwoods. So, I was very happy until I noticed the cupping. I do turn up the A/C to 80-something degrees in the afternoon when I'm not there...and because it is very humid where I live...maybe that is what is causing the cupping.

Engineered is cross-ply construction, like plywood.

The only time I've seen engineered cup, it was delaminating, which is a defect of the wood.

Engineered peaks the ends when real high moisture gets involved.

Is there any way to fix an engineered wood that peaks at the ends? I'm assuming that you can't have it sanded down and refinished.

And I always thought cupping was the result of the bottom of the plank or strip of wood being wetter than the top of the plank.

Crowning is the opposite, right. If thats true then how is it that cupping is from high rh in the house?

Also you need to keep your climate controls on all the time. This is a hotly debated issue but really its been proven time and time again that turning the climate controls off and on does NOT save you money in enegery costs. The unit actually has to work harder to compensate for the elevated temp and rh in the home. This makes the unit work more and is harder on it causing it to wear out faster.

Check the landscape surrounding for proper gradient. Check for leaks.

An easy way to check for a leak is to turn off the water at the main valve near the meter. Then wait a few minutes. If the meter is still moving then you may have a leak.

A cupped appearence from high humidity, is from the well fastened boards swelling and compressing the edges, followed closely by buckling if it gets way out of hand. It is called compression set.

Ahhh yes but is compression set always proceeded by cupping?

Does a floor have to cup to compress? Does it compress first or later after it compresses? What came first the chicken or the egg? LOL LOL LOL

Besides that, was that what you really meant?

No matter we are learning are we not?

Fact is, both situations can cause a cupped appearance.

Example 1: Take a normal, kiln-dried to 8%, solid hardwood floor and install that over a very damp crawl space where the subfloor reads 16%+ MC and that floor will cup. The cupping will be caused by the bottom of the boards getting wetter (higher MC) than the surface. This is the typical scenario in a cupped floor appearance.

Example 2: Take a normal, kiln dried to 8%, solid wood floor and install it properly over a subfloor that is within specs, say, 10% MC. The crawl space is dry and there are no dampness issues in the crawl space. The normal RH is typically inside the home is 45% on average. Now, the owners go away for a few months in the summer and turn off the HVAC. They also live in an area where the outside humidity gets pretty high in the summer and 80+ RH outside is the average in their area. They also have some very large skylights. For the sake of argument, during their vacation, the interior RH goes up to 80%+ and stays there for most of the time they're away (greenhouse effect). Now the floors were tight and fine at 45% RH but at 80%+RH, they're picking up some moisture and expanding. Since they are well nailed (as they should be), there is no where else to go but up. And that's what happens. As the boards expand in width, they "compress" against each other, crushing the wood fibers and cellular structure permanently and forcing the edges up in a cupped appearance. The biggest difference in appearance is compression set floors will had a dramatic upturn right at the seams between the boards where the middle will appear relatively flat and the edges will be very peaked. A floor cupped from moisture from below will have a more uniform concave appearance (more like a bowl) and may even have some small gaps at the seams.

Compression set is a result of the expansion of the floor boards due to taking on moisture, regardless of where the moisture came from. And generally, a floor will appear "cupped" if compression set is evident.

Compression set?

wood floors have been around for hundreds of years , and for the most part no promblems , but the houses today are built more air tight , ie:on slab with no crawl space,windows ect, the cupping from what i know most of the time is due to moisture ,well for the most part, there are so many things that come into play from the old floor to the new , some may take it upon them selfs to put a floor in with out a test becouse a wood floor is already in the house ,bad move , we put tests in many areas of a job to get a true reading ,what is in the kitchen may not be true in the bedroom , all ways do your test , with the slabs it can also change from month to month , level of rain or lack of , and what they use before the slab was poured in how it was used play apart also , it is hard to say , but do agree to have an independant test done , sometimes it may take two , bottom line is it falls back to an installer that is willing to go the extra mile , and at times it may meen not making the sale becouse it could cost almost as much to seal the floor as to install it , welcome to the world of slabs ,

I've seen this condition flatten over time........
Maybe leave it alone and see what happens. Other than that;; there is no fix that I know of.