You can get an engineered floor that is as good if not better than a solid product. We produce solid unfinished flooring but we also produce unfinished engineered flooring as well. Solid flooring typically has a 1/4" (6mm) of "sandable" or "usable" surface. Basically after you get 1/4" deep you'll hit the nail heads and so you can't sand below that point. Our engineered unfinished product has a 5mm wear layer. However, the engineered product is already pre-sanded to 80g which means once installed the amount of sanding that takes place is minimal. On a solid floor, most contractors will need to do a rough sanding to get the floor even, then one or two more cuts to get it smooth. Even if you have a very talented sander he is going to take 1/32 off in his sanding on the solid floor. That equates to roughly 3/100 which is nearly the difference between the 6mm and 5mm usable surfaces we began with. So in essence, you are getting very close to the same "usable" surface. Not to mention the engineered is more stable, will keep you from having to install a subfloor as it can be glued directly to concrete, eliminates transition issues between hardwood and tile or carpet AND should take less time to install. My two cents. Sam @ Real Wood Floors realwoodfloors.com

You need to do a little more archeological digging still. You need to know the whole construction of the floor before you can decide how best to install something new. I'd take up that plywood piece in the kitchen and see what's under it. It's higher than the surrounding floor, so needs to go. You should also be able to see from there what subfloor is under the original kitchen hardwood. It's too bad the space under your entryway is finished, but I'd still do some exploring from below to see what's under there, and to figure out the fix to stop it from squeaking. Is it drywall below or a drop ceiling? I know it probably seems like a pain to tear out drywall, but if you cut out a clean patch, like 2' x the width of the joists, it'll be relatively simple to repair. Just make sure to cut it down the center of the joists so that there's room to screw the patch piece to it later. Cut the hole under the area that squeaks the most, if you can. Have someone walk on and watch the floor from below to see what's moving. It might be as simple as pounding in a couple shims from below, or face-nailing a loose board from above. You want to find out what's underneath the hardwood. It might be laid directly on the floor joists, or there might be 10" wide boards that the hardwood is nailed to. Another thought is to take out a board in the hallway, since that's not original and you want to replace it. See what the subfloor is there. I am a bit puzzled at why, when you've stripped the kitchen down to the original hardwood, it's still higher than the hallway floor. Is your current surface perhaps not the original kitchen hardwood? Peeling back the plywood area will help determine that. BTW, I haven't heard of that stop squeaking product you linked to, so can't offer any personal opinion. And don't pour self-leveling compound over top of hardwood. It needs to go over plywood.

Hi, Worthy, I can't speak for the NAHB or how they arrived at their standard; I'm just a single, soggy southern swamp dweller. NOFMA (The Wood Flooring Manufacturers Association) says this about gaps in hardwood flooring: "Normal gaps may vary in width from "hairline" gaps thickness of stationary, to more significant gaps, up to or greater than the thickness of a quarter. The larger gaps are expected in those geographical areas associated with an extended dry heating season, and warm, mild humid summers that require little air conditioning, i.e., the Great Lakes or New England area...Plank floors, because of widths involved can shrink individually up to 3+ times as much as 2 1/4" wide strip floors."

Do you have photos? What is your style? What is your lifestyle? Who lives in the house? The wood work/trim/doors will dictate the colour range you can work in comfortably. To be clear, 'golden oak' is really ambering that happens when OIL FINISHES age. They turn orange. All by themselves...without any help from the wood below. When you sand down your old floors you will find they are beautiful (to me) wheat colour. First things first: make sure you do a SPECIES match with the new hardwood. Oak has many cousins. White Oak is not the same as Red Oak. European Oak is not the same as English Oak. European Cork Oak has NOTHING in common with European Oak. Whew. Pay the $100 fee to have a sample of your old floor sent away to a wood testing facility. They will tell you the species of your wood. You can make purchasing decisions from there. You then need to match the width of the plank, the cut (quarter, rift, plain, etc) AND the grade (Select, Common, etc). Now you can plan your colour. Things to remember: 1. Always have the wood flooring professional (not some guy who says he can do it) sand down a large patch (like the living room) of wood. Then add several colour swatches to your wood (if you want water popping, make sure he water pops the samples as well). And THEN he adds ONE COAT of the finish. 2. Never view colour swatches without a coat of finish. 3. View the colour swatches through the 5 lighting situations of the day. I normally like to see patches put down on Friday so you can view them over the weekend. By Monday you will have a very good idea of what you want and what you don't want. 4. Oil based polyurethanes turn ORANGE! 5. Oil MODIFIED polyurethanes turn YELLOW! 6. Water based polyurethanes are CLEAR and COLOURLESS! Whew. Try up loading some photos for us to see.