I recently had a 450 sq. ft. 3/4" x 5" solid birch plank floor laid in Chicago area, glued (full-trowel) and nailed/stapled. The wood sat for 2 weeks in room before being laid. After the install I noticed that there were dozens of small gaps between the boards, including some gaps on the butt ends. I understood that with a fresh install the planks wood be mostly tight. It looked a little sloppy. I brought this to the attention of the installer and he said that this is common since the wood is never perfect and that they would all be filled during sanding. They just finished sanding and there are still gaps. Most of the gaps are filled but there are several areas (dozens) where either the gap never got filled or where the filler popped out (partially or completely) at some stage of the sanding process. I brought this issue to the installer's attention again and now he is telling me that it doesn't matter any way, since there will always be contraction in the winter causing gaps. Should a freshly installed floor like this be mostly tight or is this common?

Images at http://69.20.30.212/KitchenFloorGaps/

When nailing and gluing a wood floor, It's somewhat more difficult to get the flooring real tight IF you're using an adhesive with good green grab and a memory (like Bostick's). That's because one sets the piece of flooring down in front of the tongue to engage it with the groove and then tries to move it that 1/4" into the T&G and the glue resists this movement and/or scoops up some adhesive in the groove further preventing the T&G from fully engaging. I'm just trying to explain the difficulty of gluing and nailing when using certain types of adhesives. That said, when I sand floors, I take the time to fill cracks, voids and nail holes. It just looks better. I can't prevent what may happen in the future but I can make the floor look good right now. I think your installer's explanation is weak; That since you may get gaps in the future, why bother filling them now. That's kinda like buying a new car and finding out the tires are worn and having the salesmen say, "They're gonna wear out anyway." However, the fix is easy. Just have him come and fill the cracks gaps with a matching filler and recoat the floors. Pretty simple.

Wow, that's very minor! Gary's suggestion is great.

Thanks for the unbelievably fast response. It's funny because I used the new car example on my wife, except that I compared it to buying a brand new car with slight scratches. I also thought it analogous to a new deck with cedar that has already turned gray from exposure. Anyway, thanks for providing me with a frame of reference; I really don't know what is reasonable to expect. I just thought it would be patched thoroughly, so crumbs don’t collect in the cracks (it's in a kitchen).

The installer was unwilling to patch it any more since he has "put so much time into trying to match the stain" (he was to match Mirage Java but couldn’t really come close, especially the darkness; that's a whole other saga.). He went ahead and stained it. We'll see if he patches any more.

Thanks again for donating your time.