Tips for tub overflows that nobody talks about

I actualy did this exact thing when I swapped out my old chrome trim for a brushed nickel Moen kit last summer. I followed the advice of leaving the bottom open, and it actually saved me about three weeks ago. My kid splashed a ton of water over the side, and I noticed a steady trickle coming from the bottom of the plate instead of it just disappearing into the wall cavity. When I pulled the plate off to check, the black rubber gasket had shifted slightly during installation. If I had sealed the whole thing with that GE Silicone II like I originally planned, that moisture whould have just sat against the back of the fiberglass. I ended up using a thin bead of clear Lexel around the top arch and stopped right at the 4 o'clock and 8 o'clock positions. One thing I found is that if your tub has a slight curve, getting that plate to sit flush is a total pain. I had to back off the mounting screws about a quarter turn beacuse the overflow pipe was starting to pull too hard against the back of the tub. It doesn't look perfectly seamless, but it's watertight where it needs to be and I can sleep better knowing there's a clear exit for any future leaks.

This is so cool to learn! I’m just starting to fix up my guest bath and I never would’ve thougt about leaving a gap for leaks to escape. It makes so much sense though. Since we’re talking about these overflow plates, has anyone ever tried those 'deep soak' covers that snap over the top to let the water level get higher? I’m worried they might mess with the gasket pressure or cause a flood if I forget the water is running!

If you're worried about those deep soak covers messing with the seal, just swap the whole assembly for a Watco Innovator overflow kit. It’s way better becuase it doesn't use that annoying brass linkage that always gets gunked up. It uses a snap-on faceplate that applies even pressure to the gasket without needing those two side screws that always strip or pull the pipe crooked.

I ussually run a bead of DAP Kwik Seal Ultra around the top half. It stays flexible and won't yellow like the cheap stuff. The Watco kit makes keeping that bottom 'weep hole' open much easier because the plate sits perfectly flush against the tub surface every time.

While the strategic application of sealant at the apex of the overflow plate is indeed a sound preventative measure against incidental splashing, one must ensure the substrate—wheather it be vitreous china or acrylic—is meticulously decontaminated with a high-purity solvent like denatured alcohol to facilitate a robust chemical bond. If you neglect to remove the microscopic layers of stearate-based soap residue that invariably accumulate around that flange, even the most expensive acetoxy-cure silicone will eventually delaminate, rendering your carefully placed 4-to-8 o'clock bead entirely ornamental. I also tend to scrutinize the durometer of the sponge rubber gasket, as a harder, aged seal frequently fails to compress uniformly against the irregular contours found in older cast iron castings.