The caulk around my bathtub was a science experiment. Black mold spots. Peeling edges. Gaps where water had clearly been getting through to whatever was underneath. My landlord’s semi-annual inspection was in a week and I knew this was going to cost me part of my security deposit.

I had never caulked anything. I watched two YouTube videos, spent fourteen dollars at the hardware store, and did it on a Saturday afternoon. The bathtub looked brand new. The inspection passed without a single comment about the bathroom. Here is exactly how.

Removing Old Caulk Is the Hardest Part

Buy a caulk removal tool — three dollars, looks like a plastic hook. Drag it along the old caulk bead to break the seal, then pull. For stubborn sections, a utility knife at a shallow angle. Do not dig into the tub surface.

There will be residue. Caulk remover gel — another five dollars — softens what the tool left behind. Squeeze it on, wait the time on the bottle, scrape with the plastic tool. Wipe with rubbing alcohol when done. The surface needs to be bone dry and completely clean before new caulk goes on. Any moisture, any residue, and the new caulk will not bond.

Applying New Caulk Without Making a Mess

Buy 100% silicone bathroom caulk — not acrylic, not painters caulk. Silicone handles water exposure. Cut the nozzle at a forty five degree angle, small hole. Load it in the caulk gun.

Here is the trick that changed everything: painter’s tape. Run a strip of tape along the tub, half an inch from the gap. Run another strip along the wall, same distance. Now squeeze a steady bead of caulk into the gap. Smooth it with a wet finger — one continuous motion, not back and forth. Peel the tape off immediately, before the caulk skins over. The result is a perfect, straight caulk line with zero mess on the tub or wall.

Do not use the bathtub for 24 hours. Silicone needs that full day to cure. Showering too soon ruins the seal and you start over.

The whole thing took two hours, most of which was waiting for the remover gel to work. The actual caulking was maybe ten minutes. A professional charges eighty to a hundred and fifty dollars for this. Your cost: fourteen dollars and a Saturday afternoon.