How to tile metal surround of zero clearance fireplace

[JFCBAS]

I've installed a Heatilator zero-clearance wood burning fireplace and now am doing the finish work on the surrround. I'd like to place tile up to or almost up to the firebox opening, and have seen plenty of manufacturer "gallery" photos showing this being done. The problem (for me) is that the fireplace has a 3 inch black painted sheet metal border on the sides, and a 6 inch border above the top of the firebox. Somehow I need to attach tile over this surface. A Google search doesn't yield any consensus-- one person says to place the tile right on the metal with latex modified thinset, another says some sort of epoxy, a third says attach 1/4" Hardibacker over the metal (but then you have an edge or return to deal with). The manufacturer's rep (whom I don't really trust) casually says that you can just place thinset on the metal and lay the tile as usual. Opinions? Advice? TIA.

[B]

Few people will know exactly what to do in this case because it's non-standard, so send email to the factory. Statistically speaking, a second factory rep saying the same thing as the first would change the low-confidence answer into a very high confidence answer.

-B

[SQLit]

You want to tile over the sheet metal, right?

Why not just drill the sheet metal and use what ever sticky stuff you decide to use. What ever it is it will need to be heat resistant. Big time. That is what the sheet metal is for to keep the hot fire box away from the building materials. I installed a zero clearance years a go. I just pulled the fire box assembly out the thickness of my Z brick that I was using and finished it off that way. I strongly doubt that the pictures you saw ever on an operational fire place, Pretty is as pretty does.

[RB]

If the metal gets hot when you operate the fireplace I'd worry about expansion. Steel will expand much more than tile and even if thinset would adhere to the smooth metal the sheer forces generated by the expanding tile would likely cause a failure. I'd use an intermediate layer of Hardiboard, or at least a compliant adhesive like silicone that could take the heat.

RB

JFCBAS wrote: