The floors in my home are hardwood and have been refinished once--badly. Since it is an old house, the hardwood is the subfloor, and many of the boards are stained, warped, or very uneven. some clearly have no support under the ends of the boards. I'm debating what do to. I'm afraid they're too thin to refinish and still provide support. Besides, the warping and lack of support make them unattractive anyway. I'm thinking of laying a new subfloor over them and laying either carpet or engineered hardwood, which seems easier and cleaner anyway. If I go that route, how thick does the plywood subfloor need to be? thoughts?
When you say there is no support I am wondering if there is a problem with your floor joists. If so, you need to fix this before doing anything else as this could be dangerous for your structure.
FIRST SAND BY AN ORBITAL SANDER TAKING THE FINISH OFF THE USE DENATURED ALCOHOL OR PAINT THINNER TO CLEAN THE DUST OFF THE FLOOR NEXT USE TAC RAGS TO GET THE LSFTOVER DUST THEN PAINT. IF ITS HARDWOOD 1 COAT SHOULD DO IT BUT IF ITS PINE 2 COATS . PINE IS SOFT AND ABSORBANT. I WOULD UAE AN OIL BASED ENAMEL IF YOU WANT A DURABLE FINISH AND IF YOU HAVE HIDS. HOWEVER A LATEX ENAMEL WILL SUFFICE
Yikes - be really careful - somebody might love those old wood floors - I have a feeling I would - even all busted up. How about carpet? - then you cover them but don't hurt them - you wouldn't need the subfloor then. But if you want to put down another floor you can get some really thin plywoods for a subfloor - glue it and nail it to your old floor (but that will really ruin your old floor!!!) then nail down a new oak floor over that. Oak flooring is fairly reasonable at the big stores these days. You can put down fairly thin Haridbacker which is a sort of cement board - and on that you could do ceramic tile, but it makes for a sort of cold house. There's a zillion things for floors these days. Seems like they invented something different every week for the past 10 years. But think about how far you want to raise you floors - when you put down plywood and new boards, you raise your floor at least an inch - is that going to look weird? Or perhaps you could pull out your original floor you don't like and start again.
I'm going to take a wild guess here and say that what you're calling a hardwood floor is your subfloor, meant to be structural but not pretty. Someone finished it anyway. They used to use planks, could have been any kind of wood depending on what was available locally but it's probably not a hardwood. It was often 1x6, not plywood as we use today, sometimes laid diagonally, sometimes not. That's why it's so poor. It was not meant as the finish flooring. First before anything, you'll have to make sure it's supported properly, or at least check why those boards are moving. There's no point installing anything on top of parts that aren't supported. Then I would use plywood, flooring grade T & G, minimum 5/8 or whatever your local code calls for, screwed down. Even if you're not getting an inspection, thinner than that will flex and cause problems and is worth every extra penny. Some idiot installed subfloor too thin in one part of my house, saving himself about $40, and the floor bounced when you walked on it. I had to add the 5/8 on top of it.
1/4 luan put a dimpled barrier between the luan and the engineered floor. Be sure the floor is level or the install will be hell. Depending on the age of the house and the quality of construction it isn't uncommon to have T&G flooring nailed directly to the joists as a finished floor. In the old days, they often didn't use things like sub floors, and plywood only became popular after WW II. When you put the luan on screw it down with #8x 2-1/2 screws so you eliminate the chance for squeaks. Be sure you keep it level. If the floor is really out of plumb use 1/2. Check the studs under the room to be sure they are intact. If it's an older home those studs are normally as hard as iron. A resto nut like myself would pull all the old flooring lay down a proper subfloor. Then turn the slats over and resand and replace. The whole original to the house charecter thing. There are bragging rights in there somewhere. Those slats should be 3/4 thick. You couldnt buy them unless you were very well off.
