that's coming along nicely! "just 270g" ? LOL.

Looking good! Curious what your finishing plans are around the tank as I thought it was all just going to be drywalled in with some casing around the tank.

I had multiple people tell me not to have the drywall against the tank with the non supported ~5 inches between tank top and framing. So I am going to get the cabinetry contractor to build our wood wrap down over the gap. The bottom section is tile up to the sand line, and the top is an espresso wood with a brushed metal trim. The two doors on the front will have a built in overlap so no light leaks out.

Big question Steve, cement fibre board or good ol' drywall to tile to? I originally thought cement board but have had a couple people tell me it's not necessary and is only really used in shower installs. Tiled back splashes use drywall.

Opinions?

Drywall is fine for a tile backer for this purpose. If you have extra lying around, better to use that than sending it to the landfill. Two reasons people might stay clear from drywall for a tile backer is moisture (not an issue here) and weight (a large wall of heavy tile could in theory pull the paper off the wall board, again not an issue here). Other options to consider is the cement board which is a PITA so say the least or a tile backer board which is much lighter and easier to work with. Also consider using OBS board as it's cheap and will offer a great surface for adhesive. If it was me I wouldn't bother with using messy mortar either, PL premium or a tile adhesive would be my choice.

Thanks Steve. Unfortunately I have to deal with some cement board around the fireplace. But if I can save myself some hassle around the tank that's great!

Are you sure? I have drywall around both our fireplaces. It's non combustible, perfectly acceptable by code.

Nope, I am not sure. The fireplace manufacturer's instructions state where the non-combustible zone is and then gave an example of an acceptable material which was cement fibre board. I will give the city a call and ask them if fire rated gypsum is ok.

This is how my fireplace was originally finished by the builders, pretty sure it's just standard drywall as well, not fire rated.

Just spoke with the City building inspector and as far as he's concerned the paper on the drywall is a combustible. Cement fibre board it is!

Always interesting to hear what different inspectors have to say. I've always been told drywall is non-combustible and even though I would agree the paper is combustible that really doesn't have much to do with it. In reality it has to meet a certain standard probably something like ASTM E136. In any case, no big deal, best to keep the inspectors happy IME.