The previous owner of my house laid slate tile over hardwood in the entryway. A 9 square foot area has become loose and I need to re-set the tiles. Pulling everything out is not an option; I'm wondering how to make best of a bad situation.

Several products I've seen say specifically "don't apply directly to hardwood" (eg http://www.custombuildingproducts.com/TDS/TDS-133.pdf). I'm wondering if using an appropriate primer first will make success more likely, such as CBP's Multi-Surface Bonding Primer (http://www.custombuildingproducts.com/TDS/TDS-115.pdf). They describe it as "polymer-modified mortar ... for tiling difficult surfaces, such as plywood, vinyl and laminates, and for hard-to-bond, nonporous tile, such as porcelain and glass."

More generally, when a tile adhesive says "don't use directly on" hardwood or another surface is this because the product will perform poorly or because there could be unintended consequences (eg chemical reaction).

  • 1
    no on the chemical reaction part.
    – dandavis
    Commented Dec 15, 2017 at 12:23
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    The surface you're attaching to is probably not the wood, but a polythene based varnish or finish. One reason for failure may be different rates of expansion between the wood and the slate tile. Thus, perhaps, an elastomeric compound will do a better (and yes, unconventional) job.
    – Bryce
    Commented Dec 17, 2017 at 5:19

1 Answer 1


The problem isn't the finish of the wood, it is expansion and contraction. Wood moves a lot, even more so in entries. Only 2 options: take it out and use plywood over the wood and then tile, or keep making repairs.

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