Osb is not usually a recommended subfloor for nailing. Why not consider a floating floor of engineered wood? As far as the environmental issues goes almost all oak or major hardwood lines reforest and use environmentally friendly harvesting. Some exotic woods may not. I wouldn't worry about that aspect as much.

I am double posting this (from Design Dilemma) because I hope for professional flooring advice and also suggestions from people who've done this. We live in the Pacific Northwest (rainy winters and dry summers). Our house is 13 years old with ¾” OSB subfloors on joists 16” on center. We want to remove the carpeting in the dining room, living room and hallway (above grade) and downstairs hallway (on grade), and replace the carpeting with wood flooring. We also want to keep the height difference between these rooms and the adjoining tiled kitchen to a minimum. Because of this requirement, I am leaning towards 1/2" engineered wood rather than solid 3/4" wood. The new flooring would be professionally installed. Am I correct to say that OSB does not hold nails/staples as well as plywood for nail-down installation, nor does it provide a suitable surface for glue-down engineered wood flooring installation? Would glue-down installation avoid the squeeky-squeeks that might result from a nail-down installation? We have heard that installers recommend having an underlayment put down over the OSB to provide a better adhesive surface for engineered wood flooring and we would have that done. I don't think a floating floor would be an option because of the upstairs room size (50' x 15') and high ceilings (possibly too noisy). For glue-down engineered wood flooring, what underlayment would be best between the OSB subfloor and the engineered wood floor? How thick would it need to be? Thank you Mary

He won't warrant it because you have made a material change by installing new flooring. Your only options will be to tolerate it or remove the new flooring and screw things down then replace the new flooring. Too bad you didn't check the subfloor before you installed the new flooring. Houses shrink and settle a lot during the first year or two. Your home is a good illustration of why you might want to wait to finish a basement or install a moveable basement ceiling. It certainly makes access easier to deal with flooring, plumbing and electrical issues.

We would categorize most of these as minor installation issues. The BUCKLING on the end boards is not supposed to happen. Was the board fit UNDERNEATH the baseboards or did they REMOVE the base boards and install up to the drywall? The milling issue with the plank that has a poorly aligned end edge should not have been installed...but you mentioned the amount delivered to the house was VERY tight on square footage. Someone probably made the executive decision to put it in and hope for the best. The H joint - just the one - is not nice but nothing 'exciting'. If this happened throughout an entire room now you have cause to worry. The scratches should not be there. The pin hole isn't nice either. It was either there because someone nailed through it or it was there because it came from the factory that way. Hard to say but certainly annoying. The BUCKLING needs to be fixed. That can NOT be left in place. These get pulled and reinstalled. And if that means removing the baseboard again...then not your fault. As for the rest, I would ask for discounts. I know you want perfection but the building industry doesn't have that word in it's repertoire. Getting discounts is a nice bonus. Having money in your pocket at the end of a renovation is a HUGE advantage. Now for the tile, I would be careful with the subfloor structure. Tile on wood is allowed....so long as the subfloor has the appropriate deflection rating. That is when the joist measurements (on-centre measurement) is added to the TOTAL THICKNESS of the subfloor (two layers at least) to get a deflection rating. The tile you have ordered/purchased has a MINIMUM deflection rating. The subfloor will need to MEET or EXCEED the deflection rating. And THAT'S where 'underlayment' comes in. Plywood is regularly used to 'stiffen' a subfloor to achieve a deflection rating. Unfortunately they are doing the tile LAST....which means it is entirely possible the tile will sit HIGHER than the hardwood. I'm not sure if it will or if it won't. You will need to speak with the GC (flooring guy you hired...not his subs).