We are starting the process of remodeling our bathroom. It will be a gut remodel including a new floor. Our home was built in 1947 and we found asbestos squares in our basement under carpeting. Our bathroom floor is more than one inch higher than the hallway floor that leads to it. It is currently covered in sheet vinyl which was laid over ceramic hex tiles. Those two layers account for a little less than 1\2 inch depth. We don't know what is under the layers that we can see but a contractor that was giving us a quote thought it was possible that a subfloor was placed over asbestos to seal it in. If this is true, how do we check without disturbing the underlying asbestos? If we need to pull up the subfloor to see what's underneath it is possible that the squares will be damaged/disturbed but it is difficult justify the expense of bringing in experts ONLY to find that the depth is the result of a bad flooring job and not asbestos?

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    In that era, ceramic tile was typically done on a mortarbed whcih is relatively thick. To rule asbestos in or out you are going to have to get a sample from the suspect area.
    – Ecnerwal
    Feb 3, 2022 at 2:51
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    Congrats on asking what is possibly the most reasonable and answerable asbestos related question I've seen on this site.
    – FreeMan
    Feb 3, 2022 at 14:48

1 Answer 1


I am not an asbestos expert, but have dealt with it at multiple properties.

You mentioned the floor is covered with sheet vinyl. Note that sheet vinyl itself can contain asbestos so your overall risk may not just be under the sub-floor.

It seems like you have a simple choice, which is to either:

  1. Leave it alone and find a way to stay with the bathroom floor you have (remembering that asbestos is safe as long as it remains sealed in and undisturbed); or
  2. Decide that you need to remodel the floor; accept that the floor/subfloor will be disturbed, and accept that asbestos risk/testing is unavoidable.

If you go with option 2, since you can't eliminate the risk of disturbing asbestos, you have to rely on the next best alternatives, which are to isolate and mimimise the risk.

Isolate by using all the usual precautions to contain asbestos dust (remove furniture, wear protective gear, use plastic drop sheets, spray the sample area with water to minimise dust production, etc.)

Minimise by sampling the smallest possible area. Rather than ripping up tiles, would it be possible to drill a couple of relatively small exploratory test holes into the floor (perhaps through the grout rather than through a tile) to collect dust for testing? Obviously this would need to be done with considerable care to avoid generation of airborne dust (and of course to avoid any pipes under the floor!). Alternately, chipping away at a small area near a corner may be a better method of sample collection.

If you're not comfortable with managing this yourself, you probably have no choice but to call in experts. (In some jurisdictions, calling in experts may be mandatory.) Yes, it is a cost that may not be required if it turns out there is no asbestos. You have no way of knowing in advance. It's one of the many frustrations of renovating an older building, as I have experienced first hand myself. Good luck!

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