I am working on a new bathroom and have a question about underlayment?

Question

This is a new addition. Can I just get the self leveling underlayment before I vinyl or do I need a 1/4' wood subfllor

Answer 1

Hello,
The correct answer is kind of here already, but spread over several replies.
First: Is the subfloor wood or concrete?
If its concrete You can install vinyl directly on top as long as the subfloor is smooth and level. if its not, you can use a self leveling product, NOT fix-all!
If the subfloor is wood floorboards, you need some type of underlayment; wonderboard, hardibacker, plywood, or particleboard. I install thousands of square feet a year, and prefer particleboard if I have a choice. However, sometimes I don't have the clearance (door jambs, cabinets, etc.) In that case, I generally use 1/4 AC plywood smooth side up. The X designates exterior grade which cost a few dollars more and is not necessary. Since this is a new addition, you probably already have a plywood subfloor, in which case you can use any type of sheet underlayment you prefer. Hardibacker and Wonderboard are easier to handle because they are 3x5 feet(plywood and particleboard are 4x8). However they will expose use to toxic dust.
P.S. In spite of what the answerer below might think, both Hardibacker and Wonderboard are used as underlayment for ALL types of rigid flooring. Perhaps he should check their websites!

Answer 2

No one ever READS the question. If you are putting VINYL flooring down, you do not put it over cement board (HardiBacker, Wonderboard, Durock, etc. are all cement board products for use under CERAMIC or QUARRY tiles!)

Your subfloor is probably OSB or plywood. Use 1/4" lauan (pronounced lew'-on) underlayment. It needs to be nailed using underlayment nails or using staples with a pneumatic stapler. You have to put a LOT of nails in it (laid out on a 4" grid!)

Now, somebody here is going to say, "No, no - don't use lauan! It will void your vinyl flooring warranty!" This is not usually true. The lauan plywood needs to be made with exterior glue to be acceptable. All lauan is now made that way. About 10 years ago, some companies were selling lauan that did not have exterior glue, and there were problems.

Answer 3

for a concrete floor you will want the floor clean and smooth if you have cracks then float over them a couple of times, then glue the vinyl down. If it is a sturdy wood floor with no soft spots 1/4 particle board will work, screw it down and float over it with a floor leveler, don't use fix all or vitex it pops and cracks loose easly. if you go to home depot get armstrong grey floor patch. then glue the vinyl down and trim it out. If you have soft spots go to 1/2 particle board. You can also use plywood with a smooth finish like acx or ccx.

Answer 4

On all my sub floors I used "wonder-board" the cement board in 1/2 inch. It's heavy but, nice to work with and makes a good solid floor.
A wooden sub-floor is O.K. if you use, say, 1/2 inch ply board or something as substantial. If you use a 1/4 inch underlayment and it's not solid on the floor your going to have trouble down the line with "soft" spots and your tile or lino will be coming loose.
Also, use a good primer for the lino or tile, it will hold much better in fact, I use two coats of primer before a tile or lino job and make sure you let them dry good.

Answer 5

The other answers are ok for tile floors, for vinly flooring you can use 1/4" underlay be sure to SCREW it down . Rember to fill and sand all the joints, also glue the sub floor with a good glue ie, P/L prem.to avoid squeeks latter. Good luck, Odd-Jobs , Great & Small, Ottawa Ont. CA

Answer 6

I have heard contractors using a wall board, concrete, and plaster patch called "Fix-all" good luck.