Hi,

I'm trying to get a laminate floor I bought at a steal installed... I've left the installation itself to the pros, but they want some exorbitant amount of money to level it ($925, not including materials).

It's concrete, I'm pulling up the previous parquet (there's glue underneath) myself.

How much floor leveler should I need for 540 sq feet?

How much floor leveler should I need for 540 sq feet?

That's really an impossible question, site unseen. Typical coverage is usually about 45 sf or so at 1/8" thick per 50 lb bag. But... all floor coverings have a tolerance listed within the instructions, such as maximum variance of 1/4" within 10' and no more than 1/16" within any 12" but that does not mean it has to be level within those parameters, just flat within those parameters.

Level is a whole different ball game. You only need flat and if you were to try for level, you might be shocked at how not level your floor actually is.

Once you get the old floor off, and the old adhesive scraped away, use a straightedge to check the floor. A good 8 foot straight edge, where you see light, mark with a sharpie marker and build it up, if it rocks, you can grind it down, but, if it's within the tolerances in the written instructions for your floor, you needn't do a thing.

Furthermore, the "NYC" in your screen name, I'll assume your in New York City and the slab, if on an upper floor of a high rise might be a lightweight concrete, not regular concrete. If so, portland based levelers are not compatible with lightweight, gypsum based floors.

Why not go over the existing floor? That's one of the beautiful things about laminates.

Why not go over the existing floor? That's one of the beautiful things about laminates.

Well the existing floor is definitely not level, and I'm afraid of it warping should moisture ever get down there (we have a problem toilet). I've had people recommend the following ideas:

1) Get soundproofing underlayment, that will often flatten things out sufficiently
2) Screw down a plywood subfloor
3) Scrape up the glue, pour leveler, put underlayment (most expensive route)

I'm afraid of it warping should moisture ever get down there (we have a problem toilet).
Laminates and toilets don't go together very well. No matter what kind of deal you got on the floor, find something else for the bathroom and fix the toilet problem.


1) Get soundproofing underlayment, that will often flatten things out sufficiently

Any sound proofing underlayment will follow the contour of your floor.


Screw down a plywood subfloor

You are really overdoing things with this one.


Scrape up the glue, pour leveler,.

Once again, leveler is something that is not needed. All you need is a floor patch in those areas that need to be skimmed out to provide a more plane surface. Floor patches are less expensive than levelers and the difference between the two is that levelers seek level, floor patches stay where you put them.

If the floor was OK for parquet flooring to be glued down at one point, it's going to not be that bad off for laminate. It's not unusual when you start removing it that those areas that seem to be sort of peaked are really sort of debonded sections of parquet flooring. Seriously, try pulling up a section, it's all going anyway, you really need to physically examine the slab anyway.


... put underlayment (most expensive route)

No matter what you use or how you prep the floor for your laminate, you will need to use a laminate underlayment. An installation on a slab will first need a vapor barrier of 6 mil plastic sheeting, then a foam underlayment. The foam comes in a couple varieties. Some is just a cheap thin foam, nothing else, some is a thin cheap foam with an attached 6 mil plastic with a little bit for an overlap of plastic, both of these provide the minimum required underlayment as needed for accommodating minimum variations in plane of the subsurface and the latter is supposed to also accommodate the vapor barrier requirement as needed. Last is the denser foam, often green or blue, closed cell foam that is the "premium" underlayment. The premium underlayment dampens the impact noise of walking and dropping things on it so the floor has less of a hollow sound.

I've never been able to tell the difference in sound between the regular foam and denser foam and over a mass such as a slab, you would only need the quality of the regular foam, that is, it the laminate you bought did not already have the foam already attached to each plank. Locally, the only place carrying the budget foam without the attached 6 mil poly is one small mom and pop flooring store and BJ's club. I bring this up because price wise it is much cheaper to get large rolls of 6 mil plastic sheeting at a big box or paint store and have much larger and seamless coverage and then use the cheap foam only underlayment.

Lastly, once the flooring is up, it will be much less expensive mark high spots on the floor and rent a grinder to knock them down. Let the rental place know what you are doing and they will set you up with a dust collection system. Once the highs are knocked down, you can build up low spots with layers of 15 lb or 30 lb roofing felt. Since it's asphalt paper, you can adhere layers together using any vinyl composition tile adhesive that lists "cutback adhesive residue as an acceptable substrate. Cutback adhesive is an asphalt based floor adhesive. This process would be the least expensive way to go.

Once your floor is ready, and you've done actually all the hard work, you'll be shaking your head in disbelief as you watch them install a floor that is not much different than putting together Legos. You will have done ALL the hard work.

Good luck

Laminates and toilets don't go together very well. No matter what kind of deal you got on the floor, find something else for the bathroom and fix the toilet problem.



Any sound proofing underlayment will follow the contour of your floor.



You are really overdoing things with this one.



Once again, leveler is something that is not needed. All you need is a floor patch in those areas that need to be skimmed out to provide a more plane surface. Floor patches are less expensive than levelers and the difference between the two is that levelers seek level, floor patches stay where you put them.

If the floor was ok for parquet flooring to be glued down at one point, it's gonna not be that bad off for laminate. It's not unusual when you start removing it that those areas that seem to be sort of peaked are really sort of debonded sections of parquet flooring. Seriously, try pulling up a section, it's all going anyway, you really need to physically examine the slab anyway.



No matter what you use or how you prep the floor for your laminate, you will need to use a laminate underlayment. An installation on a slab will first need a vapor barrier of 6 mil plastic sheeting, then a foam underlayment. The foam comes in a couple varieties. Some is just a cheap thin foam, nothing else, some is a thin cheap foam with an attached 6 mil plastic with a little bit for an overlap of plastic, both of these provide the minimum required underlayment as needed for accommodating minimum variations in plane of the subsurface and the latter is supposed to also accommodate the vapor barrier requirement as needed. Last is the denser foam, often green or blue, closed cell foam that is the "premium" underlayment. The premium underlayment dampens the impact noise of walking and dropping things on it so the floor has less of a hollow sound.

I've never been able to tell the difference in sound between the regular foam and denser foam and over a mass such as a slab, you would only need the quality of the regular foam, that is, it the laminate you bought did not already have the foam already attached to each plank. Locally, the only place carrying the budget foam without the attached 6 mil poly is one small mom and pop flooring store and BJ's club. I bring this up because price wise it is much cheaper to get large rolls of 6 mil plastic sheeting at a big box or paint store and have much larger and seamless coverage and then use the cheap foam only underlayment.

Lastly, once the flooring is up, it will be much less expensive mark high spots on the floor and rent a grinder to knock them down. Let the rental place know what you are doing and they will set you up with a dust collection system. Once the highs are knocked down, you can build up low spots with layers of 15 lb or 30 lb roofing felt. since it's asphalt paper, you can adhere layers together using any vinyl composition tile adhesive that lists "cutback adhesive residue as an acceptable substrate. Cutback adhesive is an asphalt based floor adhesive. This process would be the least expensive way to go.

Once your floor is ready, and you've done actually all the hard work, you'll be shaking your head in disbelief as you watch them install a floor that is not much different than putting together Legos. You will have done ALL the hard work.

Good luck

Thanks! I just pulled up about a 4x4' section to see what's what. TAR. The installers used tar to install the previous parquet... this stuff doesn't come up easily at all. Essentially it's a tacky layer of shallow grooves that is going to make this a nightmare :(