Best of bad condo gypcrete/floorcovering choices?

Discussion in 'Floor Preparation' started by Lifechoices, Apr 13, 2019.

  1. Lifechoices

    Lifechoices Member

    I’ve got a 3rd-floor early-80s 800 sqft rental condo that I used to live in, and it’s done well by me for almost 20 years, fully rented, no skipped payments, no complaints. While I was still living there, I ripped out a lot of the old carpet, found a horrorshow of cracked and crumbling gypcrete, but was too young and dumb to even ask what I was looking at. Instead I put down hella underlayment and covered it all up with a floating Kahrs 7mm veneer product. Surprisingly enough, that’s done very well through these rental years and five or six sets of tenants, but it’s now beyond worn. The bedroom that still has carpeting also needs new and the bathroom vinyl needs replacing — there’s also a little slightly depressed spot I just discovered near the toilet that I’m guessing represents a wax seal leak. It’s about 10” around.

    To make things worse, the building itself may have some structural issues — it’s built on fill dirt, has a wood foundation that probably wasn’t laid properly. So there’s a bit of a slope to a couple of the rooms now, too — it seems like there’s an inflection point over what’s probably a joist.

    On the upside, there’s no movement/rice-crispie gypcrete noise underfoot. Floor still seems pretty solid, just uneven.

    My first instinct was to do it right, rip out the old crumbled gypcrete, patch and repour whatever needed doing — until I saw the price tag. They want around $10/sqft just for repair. There’s no way to make that pay back in any timely way, and it’d represent a substantial chunk of the value of the condo itself. The condo management is also having engineers come look at the building, but not for a few months, and my window for flooring between tenants is narrow. The last thing I want to do is spend a lot on gypcrete repair only to have it torn up again or cracked if they decide they need to jack the building. My guess is they just leave it, and the new floor does what it does in response to the floor slope and its causes.

    I’m considering doing a temporary floating fix through a lot of the condo: either take up the old floating floor and replace with a new one or just lay the new flooring right over the old, just put it at 90 degrees. (I’ll probably go with the same Kahrs product.) Given the strange little depression in the bathroom, I figure I should pull that all up and make sure there’s not a water problem in there, and that’ll mean I definitely have to repair or repour the gyp before putting down new plank vinyl. And then the bedroom with carpet...I’m worried about that one because I’m afraid the carpet strips will come up with the carpet, and then I’ll have to do a gyp repair on that whole room, rather than just paying for carpet. But I don’t see a way around it: the carpet needs replaced.

    I’m aware that both the gypcrete and the structural issues have to be addressed eventually. To some extent the structural issues are out of my hands, as is the timeline for inspecting/fixing them. My instinct is actually to sell and get out of that building, but that’s not something I can do right now, so it’ll have to live on as a rental for at least a few more years. At sale I’d take the hit either way: repair the subfloor so that it’s good for the sale or cut the price pretty hard to reflect the work that needs doing. Worst of both worlds: spend the money on the floor, have it break up again, then try to sell.

    Given all that, what advice would you have? Does laying the new floating floor on the cracked/bad but apparently still functional gyp make sense until the building issues can be dealt with? Would laying the new 7mm floor right over the old be a substantial weight problem? Any thoughts on the bathroom and bedroom?
  2. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

  3. Lifechoices

    Lifechoices Member

    Thanks, Mike. Yeah, a full-on self-leveling repair with the mesh would be wonderful, and would also be smart given the beating that tenants give a floor, but until I can pay for that, patching with one of their products may have to do. I’ll get in touch and see what they recommend. I’m confused by their RR product — they say it’s suitable for gypsum but I see it’s got a little Portland in there, and everything I’ve read says mixing the two is a bad idea.
  4. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    The two do not bond properly if you are not aware of it. But if you follow manufacturers recommendations for product designed for the application(ex.specific primers)then it’s acceptable. The chemical engineers know what they’re doing with their formulations. I was told at Mapei headquarters training that there is Gypsum in Portland, how much? I don’t know. Schonox training was pretty impressive at some classes at the convention. Once you familiarize yourself with their products and watch some videos etc. I’d start small, gain that knowledge and expand.

    Distributor may be an issue to order your product.
    Last edited: Apr 13, 2019
  5. kwfloors

    kwfloors Fuzz on the brain Charter Member Senior Member

    I would talk to Uzin also.
  6. Lifechoices

    Lifechoices Member

    Thank you both. A question about these fiberglass/polymer-reinforced self-levelers — when you pour them over, I assume they’re finding their way into the cracks and then they’re holding the remaining gyp together. Considering how thin the new layer is — I’m guessing most people don’t go past a half-inch, this stuff’s expensive — do you hear anything about how well it holds up? The leveler itself is plenty strong, but I wonder if the old gypcrete is continuing to get beat up and crumbling to dust underneath. I’m thinking that when I do a real repair on this, if I’m going to pay serious money, it may as well last a couple-few decades.

    I probably will bite the bullet anyhow and use the self-leveler in the bedroom — that gets a lot of weight in one spot for a lot of hours every day, and I imagine that now that it’s falling apart in there it’ll deteriorate pretty fast. Other areas don’t get the same abuse. Man, am I glad I don’t have this stuff in my house.
  7. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    that’s exactly what I don’t know, if it locks together,etc.

    If I sat in a training forum class it would be my first question. I assume they would say a certain deflection maximum amount and a few other specifics but you’re asking questions I would have. We are not there so it’s difficult to assess and determine effective material, and minimum amount of product.
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  8. Daris Mulkin

    Daris Mulkin The One and Only Charter Member I Support TFP Senior Member

    I guess if it is a floating floor why go to all thee bother. I'm not seeing what would tear up the gypcrete any more. But I'm a carpet installer, what ddo I know.


  9. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I guess a good assessment would be in order to make some choices.

    Acoustical tackstrip or proper nails should’ve been used.

    Check with manufacturer to see if new flooring can be installed over other flooring.

    I have a rotary laser to see exactly at different points wherever and the differences. Once you evaluate and know numbers the situation becomes tangible.
  10. Lifechoices

    Lifechoices Member

    Yeah, I think that’s the next step, and then the to-level-or-not-to-level question for the bedroom will ride on whether the structural evaluation happens before I have to replace the carpet in a couple of months. If it can’t, I’ll see if I can wait to put a few hundred pounds’ worth of compound on the floor — and ultimately it’ll come down to what has to be done to secure the carpet strips. As I recall from when I pulled out the other carpeting, it’s tackstrip — and the gypcrete just let it go. I’ll talk with the condo boss about it, since I’m sure he doesn’t want my tenant landing in the bedroom below, either. I’d actually like to wait on the whole thing but that carpet is least 25 years old, and it looks like it needs to go to the vet.

    Bathroom will just be a comprehensive job, since I have to see about that sunken spot near the toilet.

    For the rest, laying the boards over the old boards is fine, and I’m thinking might even give a bit more stiffness to the floor laid at 90 degrees. But it doesn’t look like it’ll be much more work to take up the old, patch what’s patchable and have a look at how things are doing, take some photos, put down new underlayment, and put the new stuff in. May as well take the opportunity, since the old float-in’s so easy to take up and the new boards have to be cut anyway.

    Daris, as I see it the main reason to level, once I’m ready for that job, would be to, well, level, and also stiffen up the floor — there’s a few spongy areas that aren’t the worst, if you’re renting, but you wouldn’t tolerate them in your home. I think the sponginess is mostly a factor of the underlayment used as leveling material plus the fact that a 7mm veneer board flexes, but there could also just be bounce in the subfloor at this point.

    I’ll also take the opportunity to praise this Kährs Linnea veneer product some more — I had no right to expect this much use out of it, especially with all those people moving their stuff in and out (note: grad students arrive with three times the furniture that will fit and it’s all made of glue, but they’re responsible tenants; undergrads have no furniture, but will let the place turn into a swimming pool before they text you about a leak) and it looked great up till maybe three or four years ago. It’s been fine in the kitchen, too. I did think about using something a little more durable, but as far as I can make out there’s no point in buying something sandable if you’re putting it in over gypcrete, you’ll vibrate the stuff into dust.

    Thank you all very much for your help. I feel better-equipped now, and I’ll let you know how it turns out.
    • Like Like x 2
  11. Lifechoices

    Lifechoices Member

    Good news! When the old carpet came up, I was shocked to see that the gyp was in no worse shape than the stuff in the rest of the apartment 20 years ago. Clean slab that was cracked, but not pulverized or even turned into gravel. Tack strips didn’t even come up as I’d expected. The unevenness around the room was like ice-floe pileup — not that dramatic, but you could see that if the whole building had shifted/settled and the slab cracked, some slabs would “heave” a little over the others. Since it’s fragile stuff, I expect in time it’ll wear at the crack edges and the slabs will fall reasonably even again. In any case I didn’t bother with Schonox or patching, because frankly it just looked like any stress with further settling would then re-crack the slab in new places. I had the flooring guys recarpet with some fresh padding, and you can still feel some unevenness underfoot, but nothing unreasonable for an old building.

    Similarly, in the bathroom, the flooring guys saw no water damage to the existing sheet vinyl, and the little depression I’d noted hasn’t changed since last winter. So rather than pull up the vinyl and take gyp with it, they just skimmed the depression and laid the click vinyl over. Looks tidy and much better than before; I do notice a little bit of bounce where the skim ought to be, but again, it’s not a big deal.

    I feel like I dodged a bullet there, at least temporarily. Underlayment question coming up on another thread —
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