I will be installing 2x6“ marble subway tile on a mosaic mesh for a kitchen backsplash. The backsplash will be 5 feet high to the ceiling on one wall, and up to 3.5 feet high on the wall with upper cabinets. The tiles are about 3/8” thick. Some of the tiles may be separated from the mesh during installation and installed individually due to chips or breaks or undesirable tiles or simply handling.

What surface should I install the tiles on? Current drywall or hardibacker or another surface?

I think the current drywall is covered with painted wallpaper. I can remove the wallpaper and prime/paint, but I don’t know if residual wallpaper paste would affect adhesion of thinset. Also I read in another thread that the drywall paper coating could separate.

There is a vented range hood on the area that will have the 5’ high backsplash. I am replacing it, but haven’t gotten behind there to see how it is attached or what the ductwork or electrical connection looks like. There appears to be a 1” gap between duct and drywall (see pic).

I thought about installing 1/2” hardibacker. Waterproofing is not really necessary and that stuff is a pain to install. I installed it in a shower once. I don’t know if it would make replacing or servicing the range hood more problematic. Is there a better alternative to hardibacker?

At this point, I don’t know if I am supposed to tile behind the range hood or butt the tile up to the range hood vent. Should I try to install new backerboard behind the range hood? I supposed I could temporarily remove the ductwork or replace it if I mess it up, if I can do all the work below the ceiling. My new range hood should arrive later this month and I could try a test installation.

There is electrical and plumbing work behind the drywall. The cabinets and soffit in the pic will be removed.

1. Is there another backerboard surface I should consider installing behind the tile?
2. Should I install that surface behind the range hood?
3. Should I also try to tile behind the range hood?
4. Any other tips?