I am total beginner, so please bear with me.

I live in a second floor condo unit (built around 1997). I recently removed a closet and discovered that my carpet rests on some sort of underlayment, which rests on some sort of concrete float, which rests on plywood. The concrete measures just under 1 inch. Here are some images:

Floor topview Floor underneath

You can see in the first picture that the left side was cracked while removing the closet.

Here are some close up pictures of the concrete:

Concrete Front Concrete Top Concrete Back

Additionally I have tile in my kitchen and bathroom that both also appear to rest on this concrete float. Here are my questions:

  1. Is this concrete called a float? I found this StackExchange thread, stating that this a float.

  2. How do I reinstall and/or fix the cracks I've created in the float? In the referenced StackExchange thread above, one answer states to use mortar mix, another states that I should use sakrete, and the third states I should use concrete pre-mix to re apply the float. Potentially using a "dry pack" method.

  3. I would like to replace the the carpet and tile with vinyl plank flooring. Is working with this float the best option? I would assume that if I do work with the float I would need to add and level float and install some sort of underlay, although I'm worried about cracking the concrete while removing the tile.

Thanks in advance for any help you can provide.

2 Answers 2


This looks like "gypcrete", a gypsum-based cement product used to level and stiffen subfloor and deaden inter-floor sound transmission in multi-family dwellings. I'm not familiar with the term "float", but it seams reasonable in a masonry context.

Cracks aren't a problem, but you'll need to remove all loose material and fill the voids before installing either carpet or a floating hard floor. Find a suitable local product and follow the instructions for preparation and mixing, then use a straightedge to span between undisturbed areas and achieve a flat finish.

  • 2
    AKA self-levelling compound, self-levelling underlayment, etc. The complete lack of aggregate visible in the broken bit (and typical use-case) both suggest that this is what you have.
    – Ecnerwal
    Commented Jan 30, 2023 at 18:49
  • @Ecnerwal So your saying that I can use self-leveling compound (something like this) to fill in the chipped gypcrete?
    – MGamboa
    Commented Jan 30, 2023 at 19:04
  • As long as you don't exceed the 1.5" depth limit specified, sure.
    – isherwood
    Commented Jan 30, 2023 at 19:08
  • Yup, it measures under just under 1 inch thank you so much!
    – MGamboa
    Commented Jan 30, 2023 at 19:22
  • 1
    Be sure to follow the recipe closely or you'll have powder. Folks tend to think that "self-leveling" means "as liquid as milk". That's not what the stuff is like. It's more like warm peanut butter.
    – isherwood
    Commented Jan 30, 2023 at 19:25

What I see in the pics looks like thinset. It was probably used to bring the floor up to a needed height.

I would like to replace the the carpet and tile with vinyl plank flooring. Is working with this float the best option?

If I understand your intentions, your best bet is to lay the vinyl plank over the tile. No need to remove it. Your "heavy" work will be getting the floor where the carpet is removed to the same height as the tile. Again, there is no need to remove all the thinset. Just remove any loose pieces and be sure the area is free from debris. Then fill in any spaces or cracks with new thinset. If the area is still below the height of the tile by 1/2 inch or less, use leveling compound to bring to the correct height and to get the floor smooth. Then install your LVP.

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