I'm going to install a basement subfloor. I have 2 rooms that had vinyl squares glued down - a bathroom and laundry room. Can I lay down rigid XPS insulation and plywood directly over the vinyl and not have to worry about the vinyl adding a little bit of slope in the doorway? It's really, really thin. I think not but I want to make sure.


2 Answers 2


Vinyl is a material that takes millennia to degrade. It is waterproof and is resilient enough to .walk on comfortably. It would be wise to leave the vinyl and build directly on top of it. Typically, when installing a floor in a concrete basement a vapor/moisture barrier is installed to keep the materials above it dry. Can you clarify why the vinyl would add to the slope (of the floor?)? Are you concerned with the floor being raised enough to interfere with the door bottom? If so, it is relatively simple to trim the door bottom.

  • I was concerned that the old vinyl would prop up the subfloor in areas where the subfloor is on top of it. There would be areas w/out vinyl underneath the subfloor and I was worried about this transition.
    – mj_
    Nov 3, 2015 at 21:24
  • Although the insulation board will flex somewhat (which is probably good) what ,if anything, will go on the plywood?
    – ojait
    Nov 3, 2015 at 21:57

Your subfloor will span that small gap without issue. If you're really worried, apply a small amount of construction glue or leveling compound at the edge of the vinyl to taper the transition, and lay the insulation panel into that while it's still pliable.

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