Hello again!
I am planning to install linoleum flooring in my kitchen, for that super retro look. The installation instructions stress that the underlayment must be as SMOOTH as possible. Any indentations or imperfections will show through the linoleum.

My underlayment is plywood, CDX (underlayment grade). It is pretty smooth... i had to fill a couple of small surface knots with wood filler, but mostly it's a good surface.

BUT! Installation instructions for the plywood specify that a 1/8" gap be left between all panels, for expansion.

Now, isn't that gap going to show through my linoleum?? What can I do about that? Can i FILL the gaps with wood filler? I would think not, since that pretty much defeats the purpose they serve, right?

Is it possible that the gap they specify is meant for outdoor sheathing uses only? (the instructions stamped on every piece of plywood do not say one way or the other) Would the fact that they're indoors, in a relatively controlled climate, mean I could fill those gaps and not worry about some kind of terrible expansion ruining the whole thing?

Any advice is greatly appreciated, as always!

cheers, james

labman

I see another strong vote for screwing down good whatever you use. Not sure what the membrane he mentioned is. I wanted to mention that if you are using a natural oil based product and apply it over nasty old black adhesive, it could bleed through it. Maybe the membrane is something that will stop that.

I haven't had problems with th eblack bleeding through either the vinyl floors, or the one poured epoxy I did.

jamlove

As always, thanks for all the input. When I put down the CDX plywood, I used both ring-shank nails and 3 1/2" gold screws. I didnt' want that sucker to ever move! It's installed over top of the old subfloor, which is 3/4" thick lap boards, laid diagonally to the joists. This gives me a total subfloor thickness of 1 1/2", which I'm confident will be sufficient.

I'm going to skip using lauan plywood for 3 reasons:

1. The instructions say to
2. More expense
3. Would cause a greater transition between the dining room and kitchen floors, which might look weird, plus be prone to damage from foot traffic...

The linoleum tiles are supposed to be delivered after Christmas, so I have some time to continue sanding the floor smooth where I filled the small knots and covered over my screws.

I'll leave small gaps for expansion, and then plan my tile placement accordingly so there are no seams near these gaps. Hopefully it'll work out!

Thanks again, j

labman

If you put down new plywood, that eliminates any problem with old adhesive. Like I say, I have taken up tile over gaps and not seen any problem. Interesting thing was a floor done in the 50's, the Pastor's study at my church. The underpayment was a fairly soft material, I think maybe called soft board, softer than hardboard. After about 50 years, it still looked good over the gaps. I quietly let the old tile go in the trash without ever pointing out it may have contained asbestos and been hazardous waste. We carpeted over the soft board, no problem.

Aside from the thickness, what is the difference between luan and plywood? Does luan have some oil in it that would be a problem?

Lotta

instructions from forbo website.
______________________________

Like other resilient flooring, linoleum telegraphs the shape of whatever’s underneath. Glue tiles to existing vinyl only if it is a single layer, relatively smooth and not cushioned.

Otherwise, prep the floor:

Option 1: Install underlayment (special plywood with all voids plugged, one surface sanded and edges milled to interlock). Forbo recommends dispersion-type staples; nails can pop up. Fasten every 4 to 6 inches in the field and every 2 to 3 inches along seams. Sand seams flat.

Option 2: If the old flooring is in relatively good shape and not too cushioned, fill gaps with a floor-leveling compound made with Portland cement and a liquid latex binder. Do not use gypsum-based fillers; they may harbor mildew and interfere with the linoleum adhesive.

______________________


When I have installed flooring I have always filled the gaps or any depression (from the screws that I used to secure the underlayment). I have used floor leveler for this purpose. The floors always come out smooth.

The width of the gap and whether or not to fill it may depend on the thickness of the new tile being put down. If it is of a thicker material than the smaller gaps may not transfer thru the tile. If one uses a thinner tile then the smaller gaps may have a tendency to appear.

frekasiii

The finer your gaps are will reflect how fine a job you end up with. I have had past troubles with plywood firmly butted against each other leading to noise issues. Consider this especially in middle flooring situations