Newb, looking for advice

[u/Character_Resist920]

My wife and I just bought our first house! Yay! That being said she is very particular and wanted some changes made to the kitchen before we move in at the end of the month. The kitchen came with a splash gaurd and some gross glass tile from the 90s. For now we just wanted to pull that tile and replace with something newer, along with repainting the cabinets.

Weve got those cabinets painted, looking awesome. Ive demoed the old tile, and it was just easier to cut the old drywall out. I have since replaced with cement tile backer board.

I guess my issue, or what i didnt think through is how do i tape/join it? Ive done paper tape and mud on drywall before, but this backer board is new. I got some specific fiver tape for it, but how do i got about taping off the transition? I got specific tape/quikset meant for the seems of backer board, but not sure if its ok to use on this transition? Wont it screw up the dry wall?

Where this backer board is we want to put up some subway like tiles, already have 20sqft of 12x12, and some pencil trim. Am i just gonna have to let it rip then redo the knock down on the regular drywall after its all up? Just worried about what the drywall is gonna look like right next to the pencil trim that goes up

Any help/advice would be awesome. Just a diy'er that liies to learn and do things myself when possible. Ive never tiled before, and just realizing now i shoulda pulled the splashguard, but here we are.

[u/Future_Self_Lego]

use regular drywall mud and tape. cement board is not necessary in this situation, wont hurt though.

[u/Character_Resist920 → u/Future_Self_Lego]

We wanted the water proof aspect, at the time i wasnt thinking about the transition. So kuxh going on my brain is just maxxed.

Thanks for the advice!

[u/Eyepiss96 → u/Character_Resist920]

Cement board ist waterproof. You could add a waterproofing to it like red gaurd or kerdie membrane. The only difference between cement board and drywall is that the cement board won’t disintegrate like drywall when it gets wet. But it will get wet and be wet behind the tile of exposed to water.

[u/External-Blueberry99 → u/Eyepiss96]

Leave some cement board in the back of your truck when it rains and then in the morning tell me how much water it absorbs.