Do I need to use 1/8 underlayment as Sub-flooring for oak floor in older home?.?

Question

I am installing 2 1/2" wide red oak floor over a old maple tongue and groove floor some part are very irrigular. Do I need to use 1/8 underlayment (plywood type) or can I use the roll type of underlayment? Also do I need to screw down all the old floor first? I am putting hardwood flooring in the bathroom too, what is the recommended underlayment for that?

Answer 1

As long as your total thickness of underlayment is at least 3/4" you should be ok. Actually, for each layer you have, I personally would increase that minimum by 1/4"

This should not be a problem in your case.

In the bathroom you don't state if you currently have maple there.

If you currently have carpet over particle board you must rip out the particle board and put down plywood using the same formula I have outlined above.

I also agree with those that say that you should level the floor. This will help prevent squeaks and assure that the flooring doesn't work loose over time. I have never had to do this, but i wonder if you could almost do this on a row by row basis, where you nail the wood in place and then just fill in some grout type material in any gaps. At least for short gaps less than a foot I would think this would work. Maybe someone else can chime in on this.

Answer 2

All the answers have been good and right to an extent. If you have maple floors and they are level you will only need a tar paper. turn the new flooring 45 to 90 degrees from the old and nail it down. In the bathroom use a 3/4 "treated plywood sub-floor and tar paper between the two layers of wood.On a after note turning the flooring in a 45 degree angle to the walls gives the floor a unique look and stile.

Answer 3

I don't agree with much that has been said here yet. If your floor has irregularties in it already, you DO need to install an underlayment but 1/8" isn't thick enough. I know it is an extra cost ,but I wouldn't waste the money trying to put a beautiful hardwood floor down and not put atleast 1/2" plywood down. You can use the C/D grade to keep the cost to a minumun but if you don't put it down you will not get a flat floor.
To start with where the floor is already irregular, drive 8D nails partcially threw the flooring to locate the floor hoist. I have never liked those magnetic stud finders. Locate all of the joist and use a chalk line to mark them with then screw with 2 1/2" - 3" decking screws on all the bad places down untill they are flat.
Then cut your plywood so each end, ends on a joist and screw this down also or it will buckled also in a few months at the most.
I would also use flooring glue that comes in tubes for a chauking gun.
After that go ahead with the oak as if it were new work.
If you are going to rent a nailer for the flooring, there are some mailorder and online stores that sell them about as cheap as you can rent one if you aren't going to get it done in a day or so. Some people just work on a floor a couple of hours a day and it takes longer than they thought it would especially if it is a large area or several rooms.
You are going to be spending too much money and time also for this job, not to go ahead and do it right to start with. If you don't, you will have squeaks like crazy.
I let a couple talk me into putting down oak and not doing it because of the extra cost and ended up in court with them lieing like hell and the judge made me pay someone else to tear it all back out and do it right and I tried to tell them to start with what was going to happen but they wouldn't listen. I had already built them an addition and a garage that they were happy with and they called me back to do the flooring in the living room for them. I learned my lesson on that one. LOL.
Good luck and God Bless. And Marry Christmas.

P.S. When you are screwing the maple planks down you may need a helper to tap on a 2x4 block with a 3 or 4 lb. hammer as you pull the screws up tight to get them to go down.

Answer 4

Are you using 3/4" or 1/2" naildown? Unless the old foor is very bad you don't need any additional subfloor. Just run the the floor at a90 degree angle to the old. That is if the old runs north to south run the need east to west. In the bath caulk the wall gap with the best caulk you can get, before you you put down the 1/4 round. Do NOT use a concrete type patching compound. It may crack and leave you with a long term problem.

Answer 5

3/4"thick? Just use #20 or #15 tar-paper, and only use screws if there is a hideous squeak or movement. Otherwise the nails or staples will take care of the rest. As for the bathroom, same tar-paper, same install, just pray you don't have any leaks, and use a double wax seal!
I personally feel tar-paper adds a measure of protection against moisture vapor from the subfloor, that red rosin paper does not, any other installers have an opinion on that?

EDIT: Don't use any sort of patching compound. It wil crack and will leave you with a horrible crunching sound and movement. Try the link below for a little extra info.

Answer 6

Move everything out of the room , gets some Bisqueen plastic covering and cover everything and rent a sander. That's your best bet. Stripping with a harsh chemical is VERY hard on your lungs and the smell lingers in the house, not to mention messy and destructive to a lot of things that it comes in contact with. You could just do it the hard way and hand sand it or get a sander from your local hardware store and do it that way. That's about it. If you hire someone professionally, they will just sand and buff the floor with a professional sander, and stain and varnish it. You could save thousands just doing it yourself. Just do some research on the net and ask questions at your local paint store about which products they recommend to use for each step. It's easier than you think. Just very messy.

Answer 7

You will need to level the floor first with a self leveling compound then install under layment