Leveling a slanted wood floor

Q: My living room is about 12′ x 13′ with a slanted wood floor that varies over an inch from one side of the room to the next. Is there any way of leveling this slanting without destroying my downstairs neighbors ceiling and without spending gobs of money? I am also interested in laying down some sort of soundproofing underlayment such as cork which I would then top with a glueless wood flooring. Is all of this too heavy and too difficult for such an old building apartment?

A: Structural issues such as unlevelled floors are best fixed from the structure (joists). If that is not an option, you could consider this: I have seen these square tiles with delta floor backing which interlock and are intended to be used as a subfloor material. They are made of either chipboard or OSB with the heavy plastic, dimpled backing. You can use provided shims to level these squares. I have seen them at Home Depot.

It is very important when installing a floating floor that the subfloor is near dead flat. Humps in the floor are especially insurmountable, while dips can be filled with paper or these subfloor squares I mention, over the entire existing floor. Do you know the product I am referring too?

Slanted farmhouse floor

Q imported from our old site, Face Lift Floors: I have a 175-year-old farmhouse with wide plank flooring in the kitchen. It is very uneven, as well as the foundation of the house being on a downhill slant in the kitchen. What should I use to put over the existing floor – we have considered 3/8, 5/8 or 3/4″ plywood. Is this appropriate?

A: I think that would depend on what you want to accomplish by using the plywood. If you are looking for a smoother, more even surface to install a hardwood floor over, then you should be fine with 3/8 spruce plywood, screwed through the existing pine planking, into the floor joists. But this will not eliminate the slope you mention. How much of a drop is there from one end of the room to the other?

If it is very severe, then you may have to either build an additional subfloor over this, or, even better, remove the subfloor that is existing, and install shims on the joists as needed to make them all the same height. In this case, you could either use the boards you have removed as your subfloor or use 3/4 plywood.

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