Hey everyone, I've got what I think might be mold behind my shower tiles, and I'd love to get some advice. I've been dealing with humidity issues in my bathroom, which doesn't have a window and has a poorly installed vent. I've been scraping down the shower after every use and running a dehumidifier, but I'm worried about what I see. Recently, I've noticed my tile grout is cracking and making strange noises, and it looks like some tiles are poorly affixed, possibly just stuck to plywood without proper waterproofing. I thought it might just be colored mastic at first, but the dark patches seem to follow the grout lines and spread underneath the adhesive.
Do I need to remove all the tiles to clean the wall properly? Is the entire stud wall going to need replacing with waterproofing? Could the mold be a cause or consequence of my tile problems? I do have some mold killer to try out before the tiler finishes, and I'll be talking to my landlord about this, especially since they have new responsibilities to deal with mold.
3 Answers
It looks like the shower should definitely have some type of waterproof backing, like backer board with a sealant. From the picture, it seems like the tiles might just be glued directly to plywood, which can lead to moisture issues and mold. That's likely the source of your problems! Make sure to address this with your landlord right away so they can get it fixed properly.
Wait, are these tiles really glued to plywood? That sounds like a disaster waiting to happen! At least, from what you've said, your current tiler is doing it right by using proper waterproof adhesive and treating the mold. Just make sure to follow up and get everything up to code, especially if your landlord is cutting corners.
In the US, you can buy a mold test kit for around $20 that you can send off for testing to check if it's serious mold or not. It takes about two days for results and might give you some peace of mind.