So I checked the gaps again and there are more than 5 that will fit a (US!) dime, 2 that will hold a quarter, and 2 that will hold a nickle. Now that I know they are there - I can see them all the time. So tell me, am I being too picky?

Could be the low rh in winter and the wood shrunk a bit. Many manufacturer of prefinished state to install out of the box and their accliamation requirements only address the temperature and not acclimating to the rh like it should be. They do this because and also state that the rh should be in their stated zone when installed like 30 to 60% rh. Is this engineered prefinished or solid? What was the rh at time of installation?

This is a prefinished 3/4" solid hardwood Santos Mahogany- BR-111. The wood sat (in boxes) in my living room for about a week before they installed. They installed in December (4 months ago) so the humidity hasn't changed much since then.

And the rh is what in your house right now? I take it no one checked at installation.

No, for sure no one checked it before - or since. How do I do that?

At the same time, I'm really just wondering if gaps that hold a dime/quarter/nickel are acceptable. I would like to have an industry standard to point to rather than just saying "I think this looks bad", but I can't seem to find anything at all. Is there a standard for what is acceptable?

Simple, go to radio shack and buy a thermohygrometer for twenty bucks or so. You may even want to invest in a humidifier as well. I usually don't do home depot but............

http://www.homedepot.com/webapp/wcs/sto ... -100660325

Wait until the end of spring mid summer and let us know if the gaps decrease in size as the 5" wide board swells from the added humidity. We are still in the heating season, which dries out the wood, shrinking the boards dimensions across the widths. An individual 5" wide board is going to shrink and swell more than a 2¼ wide board.