Is taping behind tile necessary when drywall seams are not easily accessible?

Question

I started removing the old backsplash. Unfortunately, the drywall underneath was torn to shreds in the process and I ended up ripping it out and replacing.

This particular section of the backsplash is bounded by cabinets on top and the kitchen counter on the bottom. I left about 1" of the existing drywall on the top and bottom and was planning to just tape the seams and move on with the project.

I'm doubting myself now because as you can see, the existing drywall is in pretty rough shape, and along the bottom there are some pretty egregious gouges, so I would need to do a lot of prefilling and other prep work before taping.

Questions

1. Is it a good idea to rip out the remaining old drywall (just the visible ~1" along the top and bottom) and replace with new sheets that span the entire height from counter to cabinet?
2. If so, do I need to tape the seams? Is it even possible?
3. The left side of the drywall is floating ~6.5" from the corner because there is no stud there -- it feels pretty solid but I am a bit concerned. I may be able to get a piece of 2x4 in there and make something work, but there's not a lot of space to maneuver behind the wall there.

All things considered, nothing here needs to look pretty, but I want to make sure it is a structurally sound (and straight) surface to tile on.

Answer 1

If you’re tiling on top of the drywall, it really doesn’t need to be pretty.

You could probably get away with not taping, but mesh tape and hot mud would be good practice. Same is true for gouges — hot mud will fix that in one easy pass.

You should have a solid surface for tile on the left. If there’s excessive deflection, I’d get some framing in there.

Answer 2

It's important to tie the patch and original panels together to support the edges along the span between framing. Drywall is barely adequate as a tile substrate to begin with, and now you have a fairly narrow strip spanning between studs (press on it to see what I mean). The movement it would allow can result in cracked grout joints or broken tile. I would really want that bonded to the original sheets for support, or I'd want backing behind the joint.

If you're using heavy floor tile for your backsplash this concern becomes somewhat moot, as the tile itself will span the joint and survive minor impact. If you're using 4" wall tile or a mosaic, you really want more structure behind it.

The simplest might be setting-type joint compound or tile mortar and mesh tape. It's not really that tight in there. Use a 4-6" knife and don't leave excess mud on the surface.

Another option would be to pull the new sheets out and add backing. This could just be a floating bit of lumber between each stud, but some heavy-duty construction adhesive applied at all points of contact would really help since you won't be able to screw through the original drywall without blowing out the edges.

Answer 3

What you need to do is dependant on what the final finish will be.

A minimum of taping and mudding of the seams is required. Beyond that it depends on what you have planned.

If you plan on just texturing and painting, a lot more work is required. Definitely feathering and sanding. Texture and paint for a nice looking finish.

If you plan large format tile or an overlay of solid surface, just tape and mud. Apply your mastic or thinset and have at it.

If You plan smaller tiles that need a base with thinner notches, you need to fill the dips, gaps and valleys of the old drywall first. Then tape with mesh tape and mud. You don't need to sand, but get the seams fairly smooth. maybe just sanding down any ridges. This will make a surface strong enough for your tile, unless you have a habit of banging pots and pans into the backsplash.

If you want to go "whole hog, cost in money and time be damned", Rip out everything from the top of the counter to the bottom of the cabinets. Use 1/2 inch cement board with proper rated screws every 6 inches and seams only meeting on studs. Caulk the edges. Mud the seams and you can cover with whatever you desire.

Answer 4

You'd need to do a lot of patching to fix the upper and lower strips of drywall and the taping job would still look pretty lousy especially if you ever installed under cabinet lighting. Do yourself a favor and just replace the sheet of drywall and go the entire distance. No need to tape it, just a bead of caulk top and bottom but you'll need to add support between the studs, top and bottom. Also add some support of that edge because any force there can crack the drywall. You might decide to tile it some day.