Can I use MDF as underlayment for a vinyl floor in a bathroom? Do I have to prime it first? How will it handle the moisture? Also, I purchases a sheet of it 3/4″ MDF to use as the base of a Formica counter top. A cold beverage container was set on the sheet before I got to use it and left a very noticeable swelling where the container was sitting and sweating.
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Replies
jpf,
I don't know of any
jpf,
I don't know of any vinyl manufacturer that recommends nor allows MDF as an underlay in order to be under warranty. It would rank up there with particle board that used to be used. The slightest introduction of water causes immediate failure (there is an exterior grade of MDF, but it doesn't sound like you have that).
The kind of water that a poorly caulked tub or a slightly leaking wax ring would do.
Under formica, I've not used it but have heard it used.