Wow! We don't have any gaps that could even fit even a sheet of paper with either of our hardwood floors. We had Bruce Hardwood installed 21 years ago in a few rooms and we had pre-finished flooring installed more recently in several other rooms. In both cases we acclimated the wood more than a week. I don't know if that makes the difference. When they were installed were there gaps right then and there? Or did the gaps happen later?? Could you take photos?
When was it installed?

We do have some gaps but the installer told us when he opened the boxes that some of the boards were a bit bowed (we got them on our own, not through him) and we gave him the go-ahead to install anyway. Now would they fit any coins, I don't know. I doubt it but I'll have to take a look when I get home tonight.

We had wood floors installed in our kitchen as well this past November. They are 2 1/4 inch red oak (we matched our existing hardwood). We have MANY gaps. I actually called my floor guy back to take a look, and he insists that it is the contraction of the wood from the heat. He told me that in the warmer months (more humidity) the wood will expand and reduce the gaps. He also told me that after a year or so of total acclimation of the wood the gaps won't be as pronounced during cold weather months. HTH... I myself am waiting to see if I am satisfied with this floor job by the summer time.

I installed my hardwood myself. I am not a professional and I had NO gaps. It was during the summer though. Now that winter is here, the largest gap I have you might be able to stick a piece of paper in. I would NOT accept gaps large enough for coins. That's just poor workmanship.

The prefinished floor I had installed for a client has no gaps even large enough for paper either upon installation or several years later. Oak strip flooring finished onsite, which I have more experience with, will have some paper sized gaps when the houses are drier.

Thanks folks - that's what I expected. I have a feeling that there were some boards that were bowed and there was no checking as they laid the wood... it all went down.

So now that I know it's not right I guess I'm off to "chat" with my contractor. I hope he has the same quality standards I do. I wish there was a "rule" about what gaps are acceptable rather than my judgement. KWIM?

I had hardwood installed last summer in some pretty hot and humid weather. At the time of install there wasn't a gap to be seen and as the summer progressed it looked like the boards were slightly buckling. I noticed around December or so that gaps started showing up in places where I knew the subfloor wasn't totally level and a couple other spots. I just checked and my very biggest gap can fit a dime (only one gap this big though.)

I was seriously considering calling the installer as well so I'll be interested to hear the rest of the responses. I have heard that it can take more than a year for the wood to really acclimatize, but I don't have terribly high hopes and really don't want to have to get a whole new floor.

One of my problems (I think) is that I live in an area with very humid summers and very dry winters, and I'm not big on climate control in the house, i.e. I have the windows open at every opportunity i can get and there's no way I'll be regulating humidity, so I may be out of luck :(

Don't know if any of that really helped, but that's been my experience so far. I'm interested to hear what others have to say though.