What's the best way to renovate my wonky floor?

September 25, 2019 10:29 PM

We're redoing our kitchen flooring. We took up the old floor (floating laminate) and found sheet linoleum/vinyl that's been glued down underneath. From the 1970s era of the house, and advice from my neighbours, I am pretty sure there is asbestos in the lino and so we're planning to leave it in place. We're going to install a floating floor (marmoleum click tiles) on top, but I'm not sure how to go about levelling the floor. Or if it even need levelling.

The floor is pretty far from level (about 25 mm difference across 4m, or 1 inch over 14 feet). The lino is pretty smooth, though.

I've gotten so much conflicting advice about the best approach. Some people think that self-levelling cement should never be used on top of lino. Other people recommend different surface treatments (etching/scuffing the surface, different primers, etc).

The solution that seems the most idiot-proof to me would be to put down thin plywood on top of the lino, then self-level on top of that. Worried that might add too much height and make for awkward transitions.

Also, the previous floating flooring we took out seemed functionally fine, despite the lack of level. Having a hard time convincing my wife that we need to worry about this. Should I just install the click tiles without any levelling??

posted by beepbeepboopboop to Home & Garden (7 answers total)

Yeah don't be scuffing the surface of something that you think has asbestos in it.

I came here to say self-levelling floor screed but your minimum depth is supposed to be 25mm. So at your lowest point you're adding 50mm to the floor, before you put down your tiles (plus underlay or whatever they need). Plus more height for plywood, if you go that way - although I'm not sure it adds much - I'm even thinking that laying your screed on top of something intrinsically flexible like plywood makes it even more likely to crack, esp. a relatively thin layer.

So on balance - if it feels flat enough, I'd probably leave it as is & tile directly on top. All older houses are a bit wonky anyway.
posted by rd45 at 11:27 PM on September 25, 2019 [2 favorites]

An inch over 14' is essentially negligible.
posted by humboldt32 at 12:48 AM on September 26, 2019 [2 favorites]

Yeah, don’t mess with trying to level the floor. You’re likely to only create worse problems. A poor transition to the next room is a lot more problematic than a smoothly sloping floor. Leveling would only be advised if there would be some part of the new flooring spanning a dip.

For what it’s worth, asbestos is more likely to be in the sheet backer than in the vinyl or linoleum itself - but you never know unless you get it tested. It might be worthwhile to pay a couple hundred bucks to do testing throughout the house if you’re planning more renovations. They used asbestos in a lot of building materials in that era.
posted by Kriesa at 3:14 AM on September 26, 2019

Agreeing with the others. It’s not so important that the floor is level, as long as it’s flat. In other words, dips and wavy areas can cause problems, but a flat floor that Is a bit out of level isn’t a big deal. And if the previous floor didn’t show areas of stress you should be fine.

You could certainly lay down some thin plywood first but it might not be necessary. If you do, it’s not a big deal to hide the transition with a threshold.
posted by The Deej at 4:28 AM on September 26, 2019

Do you mean the floor is just sloped, or if you stick a 14' long board across it there's a 1" dip (or rise) in the middle? Because a sloped floor is no big deal, but I'm going to tell you that a big dip like that is going to screw with your click tile alignment, and will likely result in early failure of the connections. Remember with click flooring it's not just how it goes together at install, it's how it reacts to every footfall and bit of furniture on it. And if there's any constant wiggling of the tiles, they will eventually pull themselves apart.

As an alternative to levelling, you might go with a floating floor that uses adhesive tabs instead, or just glue/nail something down on top of the lino.

Some folks install click flooring and glue the joints, which can help a lot with future movement, but on the other hand if you don't click everything together perfectly to start you're kind of hosed.
posted by seanmpuckett at 5:01 AM on September 26, 2019

You don't need to worry about it. Marmoleum installs and most other "click tile" setups generally use a thin layer of acoustic underlayment, which in addition to providing a vapor barrier and making the tiles slide around easier during install, helps flatten and smooth out the floating tile.
posted by aspersioncast at 5:03 AM on September 26, 2019

When I wanted to pull up 1950s linoleum in my 1950s house, I took a small piece (after wetting it to reduce friability) and sent it to a lab that tests for asbestos; it came back negative. If you want to reduce your personal concern over asbestos, you can do that.
posted by davejay at 12:04 PM on September 26, 2019