Tub and shower caulk calculator

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

In Canada (Tub, 6.71 m of caulk)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

• 1 tube, 100% silicone, color-matched: About 6.71 m of joint at a 6 mm bead: about 9.42 m a tube, + 15% for tooling.
• 1 tube, Caulk remover gel: Softens old silicone so it scrapes out clean; new silicone won’t stick to old.
• 1 bottle, Isopropyl or denatured alcohol: The last wipe: soap film and remover residue off so the new bead sticks.
• 1 roll, Painter’s tape 36 mm × 55 m: Two lines along every joint for a straight, clean bead.

1. Cut the old caulk along both edges with a utility knife; pull and scrape it out (remover gel on stubborn silicone, as its label says).
2. Clean the joint: remover residue off, then rinse.
3. Dry: let the joint dry completely — overnight at least; a fan helps.
4. Fill the tub with water so the joint opens to its loaded width, then wipe the joint with alcohol.
5. Tape both sides of the joint, about 1/8″ from the gap.
6. Caulk: cut the nozzle to the bead size, run one steady bead, tool it with a wet finger or the tool, and pull the tape right away.
7. After the wait on the tube (at least 12 h; 24 h for a full set), drain the tub and use it again.

Must-have tools first, then the ones that help and the ones to rent for the day.

Mistakes that cost a callback or a second trip

• New silicone over old: It won’t stick. Every bit of the old bead comes out.
• Caulking a wet joint: Water trapped under the bead grows mildew. Dry overnight.
• Acrylic in a wet joint: It shrinks and lets go. 100% silicone where water sits.
• Skipping the tape: A wavy bead and silicone smeared on the tile.
• Too big a nozzle cut: Start small; you can always cut more.
• Showering the same day: Wait for the tube’s time: water too soon washes the bead out.

What the calculator assumes

• Tub corners: 6′ up the tile from the rim.
• Bead: the gap’s width, at least 3/16″; half as deep over backer rod.

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the code reference has more. Always confirm with your building department.

• Mildew-resistant at the tub: The building code asks for a mildew-resistant sealant at the joint between a tub and its wall finish (NBC 9.29.10.5). Confirm with your building department.

What materials do I need to re-caulk a tub or shower?

For the worked example, a tub, 22 ft of caulk, the Sheet counts 4 lines with waste included, starting with 100% silicone, color-matched (1 tube), caulk remover gel (1 tube), isopropyl or denatured alcohol (1 bottle), painter’s tape 1.41″ × 60 yd (1 roll). Each line's math is in the table above. Put in your own sizes in the re-caulk calculator and every line is counted again.

How long does it take to re-caulk a tub or shower, and can I do it myself?

About 2 to 3 hours for the worked example, in 7 steps. StudSheet stamps it DIY OK: you can do this.

What tools do I need to re-caulk a tub or shower?

8 in all. The must-haves start with caulk gun, utility knife + blades, work gloves, safety glasses. On the Sheet you mark each one as owned, to buy or to rent.

Stuck while you re-caulk a tub or shower? Ask in the Grout and caulk group of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

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