It necessarily MUST go in before baseboards, and after the walls are framed and rocked/plastered. Builders typically lay down paper, drop cloths and/or opened cardboard boxes when walking over finished flooring. This will happen and is unavoidable. Your flooring is not likely so delicate that normal construction traffic will damage it. It will get a nick here and there, and may get a tiny splotch of paint or stain on it. Besides, three weeks after the occupants move in, it will have furniture scrapes, coffee spilled, etc. Not too much to be concerned about with professional builders.

If it moved anything approaching 3/4 of an inch it would tear the nails out. There is still some skill to installing strip flooring. Let it acclimate for multiple days out of its bundles and spread out where it will be installed. Tighter in high humidity (it is going to shrink), looser in low humidity (it is going to expand). Strip floors that are to tight for the moisture content at install can buckle up and pull fasteners part way out. The humps then decrease when the humidity falls. Most of the hump will disappear. Trying to face nail (or even screw) the area will not usually work. The forces generated are larger than the fasteners and/or wood can take. Splitting is not uncommon. You have to remember that if you have 5 inch wide strips 10 feet wide you have 24 strips of wood. If each one move 1/32 inch from damp to dry, the total movement you have distributed is 3/4 inch. It only sows as the joints between the strips opening and closing by 1/32 inch though (and yes it is probbaly off by 1/32 since 24 strips only have 23 joints).

floorguy - I think I would have been much happier had you installed my floors. The things you mentioned -- minimizing the dust mess, culling out damaged planks, replacing dented boards -- are all the "right" way to do things in my opinion. That's what a contractor who has pride in his work, and who wants the customer to be satisfied, would do. By the way, the defects I mentioned are not things like mineral streaks. On some of the planks, there is a concave portion about 1/2" from the short end, so that the very end of the plank is pulled up slightly higher than the abutting plank. It looks like a "smooth dent", if that makes any sense. When I pointed this out to the installer, he said that the finish is stronger than the wood, and when it dries it sometimes pulls the end of the plank up. His solution was to lay another plank over it and smack it with a hammer so the end didn't stick up so far. It's slightly less noticeable afterward, but is still an obvious flaw that has nothing to do with the natural characteristics of the wood. You also don't sound like the kind of installer who would inadvertently leave many dents. And if you did leave dents, you would probably notice them and replace the dented planks on the spot, rather than either not noticing, or leaving this "surprise" for the customer to discover. Unfortunately the number of significant dents I've come across (at least 3 in every room) have raised a red flag. I asked the installer about the most egregious of the dents, and he admitted he should have noticed that during the install (and offered to replace the plank if it bothered me). floorguy, do you agree that having those planks cut out and new ones glued back in shouldn't be a problem? There are 5-10 planks total that would need replacement. I'd be mostly concerned that the glue wouldn't hold up as well as glue + staples, so that the plank would be more likely to work loose than the existing dented (but stapled) plank. If glued-in replacement planks are not such a big deal, I will ask the installer to replace all the ones that really bother me. And finally, what's your take on the expansion gap issue? The poster 'boxers' agreed that leaving an expansion gap is part of Hardwood Floor Installation 101. My installer made it clear that he doesn't think the expansion gap is needed, and that I'm worrying for no good reason. Yet many of the planks are butted right up against the drywall, so that when I walk the perimeter of the room I hear a lot of groaning and squeaking. Should I insist that he come back with a toe kick saw and add the gap? Maybe it would be worth hiring a floor inspector to give my opinion a little added weight? Thanks for all your replies...you've been a big help!

Some installers can work that way...you do need to clear this with the installer. And a big AND...you definitely need to consider what you're going to do with all the furniture when it comes time to finish your raw wood. Most finishers, like myself, work extra money into our estimates when floors at the same address need to be finished at different times. You know, you can rent one of those PODS to store your stuff in while the work is being done. It's called Portable on Demand Storage.