Flooring question: New over old?

Can new flooring be installed over the old flooring boards, particularly if there is no existing sub-floor in place at this time? In effect the old flooring would become the sub-floor. The existing floor boards are about 3.5 in. wide.

If it's not a problem to simply put the new floor down over the old, I would assume that at least you would never run the new flooring parallel to the old, but would have to install at either 90 or perhaps 45 degrees to the existing boards.

And isn't tar paper often laid down over the sub-flooring, to minimize squeeks?

Wayne, this was commonly done in the old days. In the old houses and factories where I have seen this done, the second course would be at 45 degrees to the first course.

Yes, tar paper is typically installed below the boards in order to minimize squeaks.

it all depnds on how solid the subfloor is if it is solid lay it in the opposite direction with a layer of brown kraft if in a damp area use 2 layers i stopped using 15# felt years ago had way to much trouble with it making noise and it does nothing to prevent squeaks it is only used for a moisture barrier the best way to install over that type of subfloor would be to install a layer of 1/4 ply 3/8 cdx ply or 1/2 cdx ply with a layer of paper before the ply or before and after i have been doing this for a living for well over 20 years and find this is the best way to have a trouble free floor

Hi...

I bought my house - a fixer-upper - 9 years ago and the first thing I did was install new hardwood floors throughout the house. No experience in that department - just figured, "how hard can it be?" Long story short, I just laid the new 2 1/4 x 3/4 oak over the 1 1/2 old stuff. No paper and for the most part it all runs the same way as the old. I guess I was lucky because I still don't have any squeaks and it all has stayed in place. I will say that I probably used a lot more staples than I needed to, but like I said... no experience will make you do that. Final result? My wife is still in love with it so I must have done a good job.

--Bobby

I would not lay it perpendicular to the old floor, because you really do want the floor to be perpendicular to the floor joists. Even if you think the existing floor is dead flat, the floor tends to move 1 joist at a time when you walk across it, and you want that movement to be resisted by the grain direction of the floor.

To picture what I am saying, think about a two pieces of t/g flooring fit together. If you try to flex this assembly across the grain, it will easily flex at the joint. If you try to flex it the other way, it will resist.

Thanks to all. And I think Lit has a good point about the joists!

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Originally Posted by Lit Jones

I would not lay it perpendicular to the old floor, because you really do want the floor to be perpendicular to the floor joists. Even if you think the existing floor is dead flat, the floor tends to move 1 joist at a time when you walk across it, and you want that movement to be resisted by the grain direction of the floor.

To picture what I am saying, think about a two pieces of t/g flooring fit together. If you try to flex this assembly across the grain, it will easily flex at the joint. If you try to flex it the other way, it will resist.

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That is a retty old school view today...BUT it appears to be a pretty old school house so it makes great sense. In the end I would REALLY prefer an inderlayment to tie the whole thing together it would make for a better floor in so many ways.

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Originally Posted by Van Huskey

That is a retty old school view today...BUT it appears to be a pretty old school house so it makes great sense. In the end I would REALLY prefer an inderlayment to tie the whole thing together it would make for a better floor in so many ways.

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if you did want to lay it in the same direction with the joist i would use 1/2 cdx then you would be fine