Thoughts on sealing a bathtub's drains

[Andyroo]

I've got a couple of 1950s-60s bathtubs down in the lower garden, from when we refit this ol' farmhouse. Thanks again to Fishdance for walking me through the 230gal in-wall-install.

The tubs hold water nicely for a time, then they leak-out, dry, then hold water again to start over. It seems tree roots are getting up & into the main/bottom drain; they're only plugged with a & needing to replace (mozzie control) but the other stuff mostly just comes back up. I'm not in any rush to kill/damage my avocado tree

SO, what thoughts on permanently sealing? I'm thinking polyurathane (5200'ish) around/under the bath-stopper, or a hard plastic or concrete disk, or maybe dome the cement in & over the hole & then seal with epoxy/polyurethane. All will be ugly if/when visible - with mud & plants I'm not terribly worried about that so long as I can get some lotus properly established, maybe some flowers, maybe some nuts, maybe some prettier guppies.

We don't suffer winter 'round here, no.

 

[wednesday13]

3m 5200 is good stuff… not sure anything will stick that well to the tub material tho. Id go with a butterfly type plug. You can take it out to drain and clean the tubs if needed also. They come in an erray of sizes and styles.

 

[zainwahid]

Hey, really appreciate the creative brainstorming here! Sealing those vintage tubs for a garden pond is such a cool idea, especially since the tree roots are playing plumber.


A couple of thoughts you might find helpful:

• Modular approach: wednesday 13’s butterfly plug idea is smart—it keeps things serviceable if you ever need to drain or clean the tubs without disturbing the seal.
• Long-term seal options: Polyurethane or epoxy over a concrete or plastic disk could be solid, but compatibility with the tub material is key. Sealants like 3M 5200 are super durable just make sure they’ll stick, as noted.
• Maintenance & ecosystem balance: Since you're planting lotus and maybe even introducing pretty guppies, keeping the system accessible matters—a good seal is only part of the equation.
• Enter the “weed rake”: As your pond beds in and begins to grow, roots or surface debris could accumulate. A weed rake could be a subtle yet useful tool here—especially when you want to delicately tidy up without disturbing the plants or seal. It lets you gently remove stringy algae, fallen leaves, or tangled roots around the drain area, which gives the seal a longer life and keeps your lotus and guppies thriving.