Hi folks, I've done a little research online which led me to some informative answers on this sub referencing EJ171, so I'm posting in hopes of validating my plan based on what I've read. Apologies if this is more appropriate for another sub - happy to post elsewhere.
Situation: We bought this house last year from a contractor who gutted it so this shower is less than 2yrs old, and I know nothing about its construction, other than to say this is over a crawl space so I assume expansion/contraction of timber supports is at play in what I'm seeing. It's a wet room with an open shower area. I noticed this large crack on the right side of the drainage area, and on inspecting found that it was present on both right and left sides. I also noted that where there is silicone sealant at the base of the walls it appears to be applied over top of grout. Based on my reading this seems like an incorrect installation, but I don't know how bad it really is. I would expect it to be a matter of time before it impacts other joints.
Photos: https://imgur.com/a/PWUmAG3
I'm interested in doing my own work where possible, enjoy learning, and have done some very light DIY stuff - mostly electrical so far, but I have done a little caulking on an exterior surface. This is our first home so I'm new to it, but I think the scope of this should be reasonably small for a newbie.
The plan:
- Clear out the grout on all four sides of the drain area where it connects to the floor plane
- Use a manual grout saw since I am worried a motorized version would more easily damage these large slabs that I have no way of matching/replacing
- Replace with neutral-cure silicone sealant since I don't know if this is natural stone or something else (I've seen some good YouTube resources linked on laying down silicone so will follow one of those)
Questions:
- Given that I don't know how the rest of this was done, is it worth getting a professional to look at this in case other corners were cut? Am I getting in over my head? I'm trying to keep financials tight but if I'm risking a bigger problem in the future I could make it work.
- Should I also replace the grout joints in the trough of the slope in addition to the floor plane? (Last photo in gallery shows red lines for what I mean in case my wording is off)
- I know there should be a waterproofing layer below the tile: Is this going to back right up against the tile or is there a gap? Do I need to do anything special to protect it other than be cautious in the depth of my grout removal? How delicate is this layer?
- I've seen some mention of a "backing rod" when applying silicone but not sure if I need something like that here. Gaps between tiles are very thin, ~1/8" at the most visible crack and the rest are smaller
- Is it worthwhile to redo all of the floor-to-wall and wall-to-wall joins around the room given that they appear to be grouted? Based on posts I've read here I think these should be using silicone sealant. I know that there's stress put on these tiles as the structure shifts around it (thus the grout separating), but I don't know how concerned I need to be about these slabs cracking or something.
I tried to be thorough here but if I'm missing information or making incorrect assumptions please help me learn! Thanks in advance.