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What should I use to repair the subfloor on a slab?

What should I use to repair the subfloor on a slab?

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Old 09-09-17, 02:55 PM
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What should I use to repair the subfloor on a slab?

My house is a tri-level. The 3rd level down is 30" below grade and on a concrete slab covered with 1x4 sleepers with solid foam panels between them and then a 1/2" plywood subfloor on top of them installed in the 1970's. The attached snapshot of the construction in progress is from an area down the hall from the bathroom where I want to do the repairs. There's some cracking in the sheet vinyl floor in the bathroom, but I can't tell if it's from a leak or just a breakdown of the vinyl. When I remove the vinyl to replace it, what should I replace the plywood and maybe the sleepers with if there is rot? I want to have the result the same height as the existing floor to prevent creating an uneven floor at the doorway. I don't know how the sleepers were installed either (masonry nails or adhesive). The products I've seen aren't thick enough and/or create a lot of seams that might be noticeable when the new vinyl flooring is installed even with leveler of some kind. I'll also need to remove and reinstall the toilet. I anticipate using loose laid sheet vinyl and don't know if it should be installed before the toilet or undercut around it and then caulked. Another bathroom can be used during the repair. The bathroom is 7' x 7' at the longest measurements and there is a shower stall and jog near the doorway and toilet to deal with. Any suggestions on how to approach this would be appreciated.
 
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Old 09-09-17, 05:44 PM
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You really can't make a decision until you see what's under there. If there was water damage, you won't know how far the water travelled until you look.
 
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Old 09-10-17, 04:13 PM
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I'm trying to anticipate what I might find. I don't know if the way the floor was constructed on the slab should be duplicated if replacement is needed. I'd also like to know about the best way to do the vinyl flooring installation. The current vinyl is fully adhered. I may need to replace the top layer of subfloor if it's too difficult to remove the old adhesive.
 
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Old 09-10-17, 06:20 PM
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I understand that you are trying to anticipate what you might find. As I said, it's all guess work. My guess is as good as yours. I don't know what else can be said.
 
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Old 09-10-17, 06:34 PM
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My first thought is not about the sleepers or the insulation, which are probably fine if the basement has been dry. Rather, that 1/2" subfloor may have been acceptable in the early 70s but not today. Look for the APA sturd-i-floor rating on the back of the plywood you use for your subfloor. 5/8" minimum nowadays. And generally you put 1/4" underlayment over that- under the vinyl- so that the next time someone replaces the floor covering, they only have to replace the underlayment, not the entire subfloor.
 
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Old 09-12-17, 10:47 AM
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One concern is that replacing the 1/2" plywood subfloor with 5/8" sturd-i-floor + 1/4" underlayment would raise it 3/8" and create a step up to trip on in the doorway. I'd also like to know the best treatment for the seam and whether some kind of material should be spread under the lose laid vinyl sheet.
 
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Old 09-12-17, 04:46 PM
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That's why you use transitions at doorways. And yes, the toilet comes out, you lay the vinyl around the mount, then you reset the toilet. If supply lines come out of the floor it's nice to remove the old shutoffs and put on new escutcheons and shutoffs after the floor is laid.

What seam are you referring to?
 
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Old 09-13-17, 10:18 AM
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I've read conflicting info. about using loose-laid vinyl in a bathroom. One source says to install it around the toilet mount before replacing the toilet and another says no heavy fixture should be placed on top of it and it should be undercut around the toilet base with the top layer then tucked in around it. Some say to caulk and others say not to.

Fortunately, the toilet supply lines come out of the wall.

The seam I'm referring to would be where the subfloor panels meet. I want to be sure it doesn't show when the vinyl is over it. I'm really not concerned about additional underlayment, especially since this vinyl wouldn't be glued down.

There is a transition strip in the doorway now that accommodates the carpet in the hall outside the bathroom. I'd like to use it the same way if possible since it works well.

If someone can tell me how to be notified by email when an answer is posted to my questions, that would be very helpful. Right now I just get to it when I have a chance to check.
 
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Old 09-13-17, 10:30 AM
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AFAIK, email notifications aren't working right now. At least I'm not getting them.
 
 

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