I would check to see if this meets code.

I don't know if there is a building code that cover this type installation. What is your wall thickness? Insulation behind it?

The niche looks to be in a bathroom. If the back wall of the niche is next to the house sheathing there really isn't a way to get insulation in. I suppose you could make the niche less deep and get some rigid foam board insulation installed but I doubt it would give you the required R value. Only other suggestion is to dispense with it, have it filled with insulation and cover it over.

I would never suggest or install a niche on the exterior wall unless the wall is packed out and can be properly insulated.

FWIW - I just “debated” this issue with SO with respect to new shower in remodeled master bathroom. He wanted to place a niche along the exterior wall of the shower. While I agreed that it would look nice, I told him that I thought the niche should be moved to an inside wall. . .

Our tile professional told us yesterday that he doesn’t install niches on outside walls due to insulation issues (unless we were willing to make some modifications to allow for proper insulation).

We remodeled our master bath 10 years ago, and I still love it. However, we had a niche put in the shower and it is on an exterior wall...there was no discussion or concern about this at the time. Now, I know so much more and would have redesigned the shower, but at the time I was clueless! Our contractor never mentioned it, and inspectors never questioned it. Our home is in Southern California, so maybe that is why. In any case, it has never been an issue, as our climate is mild all year long.

My tile installer is telling me it’s not a problem as the niche is fiberglass.

the handyman has not yet met Wonderboard nor CBP install instructions. Must be torn out to rectify.

Once torn out.......take that chance to source and hire A professional tile installer.

thanks, I’m not sure I’m understanding the issue. Can you please clarify what’s CBP? What’s the issue here?

If there is no insulation, once that niche is tiled, I’d think the only problem will be the tile will feel colder to the touch in winter than the tiles on the other walls. If the plumbing was on that wall then you’d have a serious problem, but it’s just a tiled wall.

Condensation is the problem. And condensation will cause mold.

FYI this Was supposed to be a professional tile installer. Doing it for many years, experienced...