I can't answer your question, though it could be your new floors have not "settled in" yet, or that they weren't left out to acclimate for long enough before they were installed. But I wanted to let you know there is a GW Flooring Forum with some experts who could answer your question if you want to post there, or if you want to search there for other posts describing similar problems.

Here is a link that might be useful: Gardenweb's Flooring Forum

Pelhamlady, we live in Westchester, too, and had 4" wide plank floors installed this year. We experienced the same cupping over the summer. It was really alarming. We bought a dehumidifier and ran it in the basement and the problem went away. We asked our GC why the existing floors did not have this problem and he said that the problem tended to occur with the wider boards (the rest of our oak floors are narrow planks).

I think the floor installer is probably right about the problem being transient. (But it also may come back during extremely humid periods for a few years.)

Good idea to run a dehu below, and possiby remove insulation in joist cavity underneath temporarily. (I'd just release and let it hang rather than removing entirely unless you feel it is moist.)

Get an hygrometer (or a couple of them) and monitor your spaces for awhile.

I wouldn't add another layer of poly until the issue is resolved since one of the more drastic cures is to resand which would remove all the poly anyway.

Good luck!

HTH

L

We have the same problem with our new wood floors. Our installer said that it could take many months for the floor to settle. We live in Ontario, which has humid summers and the house had a LOT of painting which contributes to the humidity. I have noticed some areas are getting better, but are certainly NOT perfect. I am waiting for the dry winter to hit, to see what happens. We had the opposite problem in our last house, where we got large gaps over the years because we did not have a humidifier on our furnace.

Beth

In the floor installation class I took, they discouraged folks from getting the wider boards (DIY installation class), due to the risk of the wider boards cupping. Seems to be a pretty common problem, no matter who does the installation.

I never had cupping in my last house which had a sometimes damp basement. But, we did have a humidifier on the furnace and ran a dehumidifier in the basement. If we didn't run those things, I guess we could have had cupping.

Hi
I just want to say thank you to all the wonderful folks who took the time to reply to my posting. My mom went into the hospital and I've been a bit busy the last few days. It's helpful to have information on the problem. I will definitely take the great advice and implement the fixes. I really hope it resolves itself. If I had any idea that this could happen, I would not have installed a wood floor. No one ever mentioned this as a potential issue - neither the lumber company nor the installer. I never thought to do additional research before the floor was installed because my other wood floors are fine (they are narrower planks though). There is always so much to learn about the renovation process!

Wood absorbs moisture and it changes shape because of that. Wide wood has the potential for more movement than narrow wood. Minor cupping in summer where you do not have air conditioning is to be expected as 100% normal.

Wood requires humidity control if it is to be held in a steady state without either cupping or shrinking. It should be installed in a climate controlled building after being allowed to acclimate to the moisture conditions of that building with the climate control on. The building, subfloor and the wood itself should be tested with a moisture meter before install. If too much moisture is present, either in the environment or in the flooring, you must wait until they equalize before installation. Your typical contractor is BAD at "just waiting" until things resolve themselves, ans so they typically install flooring without ever have tested the moisture content of anything. Thus, you can have cupping occur almost immediately when dry hardwoods are installed in a moist non climate controlled home. (In the winter, it can be the reverse. You have relatively moisture stabilized wood being installed into a dry home and it gaps.)

The biggest problem with wide plank wood floors and non conditioned environments is that you can end up with fairly large gaps between the boards when winter rolls around. The swelling of the wood in summer leads to "edge crush" along the edges where the boards meet and can't expand, so the wood fibers are crushed, leading to even larger gaps in the winter. It's especially aggravated when the floor was installed in the time of highest humidity and there is no humidifier running in the winter.

Climate control your home, and it will minimize many problems associated with the annual humidity cycle---not just the floor cupping. You'll have less seasonal movement between walls, and less gapping of moldings in winter. Your whole house will live easier.

You also need to control any humidity infiltration into your home. Moisture is the enemy of any home and you need to do all you can to keep it out. Crawlspaces should be sealed, and basements should have drainage systems installed and run dehumidfiers to a sump pump. Preferably, the slab below the basement should have been installed onto a vapor barrier rather than bare soil. It's required in all new builds these days, even in the little hick place I'm from. Gutters and downspouts should be routed away from the home, and you should make sure that the proper site grading is done to move water away from the home. All of this has an effect on not just your floors, but the rest of your home's wood skeletal structure.

Thanks so much to GreenDesigns for the great info.

I'm confused about your summer vs winter effects on the floor Green Designs. Possibly this is do to having lived in arid and semi-arid climate areas of California since I was 4. Are you assuming that summer is humid and winter air is dry due to heating?

Summer air here is pretty dry. Dry air means that even if it was very hot during the day, it is usually cool at night. So we run the whole house fan to draw in cool air at night on hot days. Thanks to good shade, decent insulation and attic fans, we rarely run air conditioning during the summer.

It would be pretty wasteful to keep the house closed up all the time and use our air conditioner in our summers when our house is very comfortable by opening it up at night and using the whole house fan.

We have mild winters so are inside air isn't as dry as in a colder climate where more heating is needed.

About 600 sq ft of 4 1/4" plank hardwood flooring is currently acclimatizing for installation in our kitchen/family room/breakfast room. Should we have bought engineered wood or narrower planks instead because we don't air condition?

What's a basement? :) Almost nothing around here where the frost like is less than an inch down has a basement. We are on a raised foundation - i.e. a crawl space between the dirt and the floor where ducts, pipes and some wiring runs. A moisture barrier has been installed over the subfloor. As is the usual practice here, the crawl space is vented, not sealed. I don't know if sealing it would even meet code.

Our grading is good and our gutters are routed away from the house.

Cloud Swift - I think you're confusing humidity and temperature. Temperature is incidental, it's the humidity that matters. Have you been east of the Rockies in the summer? Unbelievable (for those of us in the west). It's as hot or hotter than here, but their normal summer humidity is very high so you never really feel dry, more like you got a spritz from a spray bottle all the time. I've heard easterners complain about "alligator skin" when they had the misfortune of being west in the summer. LOL! So the deal with air conditioners isn't that they bring the temperature down, but that they dehumidify the house to a certain degree, therefore allowing the wide plank wood floors to shed some water content.

For those of us in the west, this means that you shouldn't install your wood floor until it has been sitting in your house acquiring the same humidity as the house air, generally 3-5 days more or less, AND you should avoid installing during a Santa Ana (too dry) or during those days when there is a tropical storm in the Gulf of Mexico and it is humid and icky here. During the winter, we're pretty good, but you should probably wait until that rare rainstorm is over, even if that takes several days.

And all that stuff about basements? It doesn't apply to us. Watching Holmes on Homes has been a real eye opener. I've learned about ice dams on the roof, frost lines and fences, weeping tiles, and dehumidifiers installed on forced air furnaces. We don't have any of those issues. Interestingly enough, Holmes once went to Altadena (LA area) and was flummoxed by various earthquake safety codes. It's all a matter of what applies to you.

suzannes, I'm not confused by temperature vs humidity. That was the point of my post. GreenD emphasized climate controlling your home and described things in terms of summer and winter that seemed to make assumptions about the humidity in either. Also he said that your crawl space should be sealed and I don't ever recall seeing a home with a sealed crawl space in California. Certainly every place I've lived with a crawl space had a vented one.

I've been east of the Rockies in the summer. Denver, Loveland, etc are east of the Rockies and quite dry in the summer. I expect you mean farther east than that, off the high plateaus. I've been in Florida in the summer (for work not by choice).

I live far enough north to not have Santa Ana's. Our GC waited until after the dry wall patching and texturing had plenty of time to dry out before bringing in the wood and it will have 3 to 5 days to acclimatize before they install.

I think that our year around (indoor) humidity doesn't vary as much as places with humid summers and, perhaps, dry indoor air from cold climate heating. There is some humidity variation year round here, but not as much.

Your wood floors are are doing that because your builder or flooring installer didn't check the moisture of the flooring and/or the sub-floor appropriately, or allow the floors to acclimate properly before installation. (There is no set time -- "until they are ready" is the correct amount of time). Any installer who doesn't do that is remiss. My 7-14" wide floors haven't moved at all. I can't believe he is telling you to wait around a few months and hope they eventually flatten out.

I see your point, Cloud Swift. So we're back to my never having heard of ice dams or mud rooms before my 59th birthday, and easties being amazed that those of us in this part of the world didn't grow up wearing bug repellent in the summertime because we don't actually have bugs to speak of.

Chapter 3 of the Wood Engineering Handbook summarizes wood movement.

Figure 3-3 shows how the shape changes depending on the grain orientation and the location in the tree the piece of wood came from.

The movement never stops as long as the humidity continues to change.

Since the change in dimension is a percentage of the size, larger boards move more.

Here is a link that might be useful: Chapter 3, Wood Handbook

I knew the Western states were dry, and that would help me with my hot swamp flashes in the middle of summer, but no bugs! No bugs? NO BUGS? Heck, I'd sell NOW (if we could afford to buy there)! Summertime sweat bees, gnats, and mosquitos and wasps and those nasty camel crickets are the bane of my husband's existence! He hates mosquito repellent but with his MS motor skills issues he has a hard time swatting the ickies and being outdoors on our 5 acres.

And yes, I'm speaking from my perspective as a Southerner, where humidities in summer are regularly in the 90% range without air, and in the 50% with it if the HVAC is sized appropriately. It's pretty balmy 65 with 97% humidity here this morning, and my AC is running and the office is too cold, but if I turn if off, it's so clammy I can't breathe.

CA and other associated states may not have the humidity cycle that causes the majority of cupping issues with eastern hardwoods, but they can have the opposite problem. If a bundle of hardwoods is shipped in from out of state and not allowed to acclimate to local conditions, that hardwood can experience gapping when installed and it dries out in situ. And, it can crack if some type of humidifier isn't installed to be able to maintain a minimum humidity of around 15%. 25-30% is more ideal. Wood is comfortable in about the same conditions that people are comfortable, both temperature wise and humidity wise. In western areas, you also have to watch the use of evaporative "swamp coolers" that work to cool a home by increasing that home's moisture content. Sometimes, that creates a too moist environment and then it needs dehumidification. You need a home hygrometer that will monitor your indoor humidity for daily content and swings. Desert/dry locations need climate control too! :)

No bugs would be overstating things a bit. Our area has misquotes, not terribly, but in the dusk and dawn they are out and biting at some times of the year. I don't recall having misquitoes when I lived in Southern Cal. We get plenty of ants - just the regular old annoying black ones, nothing stinging. Sometimes yellow jackets, but not a big problem - they will show up to join a picnic in some places.

I live in the Sacramento area. We don't get much rain, but we are in the path of drainage from the Sierras with the confluence of the Sacramento and American Rivers as well as smaller creeks and some wet land areas. We aren't extremely dry, not like Colorado or Death Valley. Daytime in the summer, it runs around 30%. Night time it goes up because the air cools.

The coastal areas of California aren't super dry either because of proximity to the ocean.

We had a swamp cooler when I was a kid, but with the usual set up - the cooler was on the roof and house air is pumped in pipes through it to be cooled by the air evaporating outside those pipes. The moisture was outside. They are uncommon now - perhaps not used at all. Our AC is a heat pump which is what pretty much everyone has.

Summer time climate control at our house when our kids aren't visiting is choosing the right time to open the windows and flip on the whole house fan supported by having attic fans with a thermostat that keep the attic air from getting much hotter than the outside air and heating the house.

We sometimes need to turn on the AC when the kids and grandkids are visiting because the heat generated by the extra people, extra cooking and such tips the balance a bit.