I'm replacing the caulk around my freestanding acrylic bathtub since it's degrading, and I noticed there's no caulk at all on the back side. Is it normal for a tub like this to be held in place only by caulk?
While removing the old caulk, I leaned on the tub and felt it shift, revealing that it pivots around the drain. Should I be concerned about this? Is there a way to secure the tub better before I recaulk? Here's a photo of the tub for reference: [Here's a photo of the tub](https://i.imgur.com/QjkJhmR.jpeg).
5 Answers
That's pretty typical! Many freestanding tubs rely on proper silicone caulking to stay in place. In some cases, a construction adhesive may be used, but it really depends on the specific tub model. A good layer of caulk should keep it stable enough.
Honestly, I’ve never come across a freestanding tub that comes with anchors. Most of the time, they’re not anchored because you can’t get access underneath to fix them if needed.
What you're experiencing is pretty standard. The drain should keep the tub in place, while the caulk prevents it from shifting. As for the lack of caulk on the back, that might have been intentional to allow for any leaks around the drain to be visible, which is important for maintenance. If it’s not in a spot likely to get spills or mop water, it’s usually not a big deal.
When you're recaulked, it's a good idea to fill the tub partially with water. This way, if it shifts when filled, you can avoid separating the caulk if it doesn’t expand correctly during use. Just be careful, as this tip is more suitable for built-in tubs than freestanding ones.
Excellent tip, thank you!
Actually, this method is a mistake for freestanding tubs. Water pickup in a built-in tub works differently!
Ever thought that the back isn’t caulked to allow for drainage visibility? If the drain leaks, you’ll want to catch it early instead of missing it from underneath.

Oh thank goodness! I was worried we'd found a new issue while trying to fix the old one.