# Tub and shower caulk calculator

> Tub, 22 ft of caulk: 1 tube of silicone for a 1/4″ bead, and 24 h before water touches it. Old caulk out, mildew killed, backer rod where the gap is wide, and the right silicone — with tubes counted from the joints you have.

## What to buy (Tub, 22 ft of caulk)

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.

| Buy | Material | How StudSheet counts it | What it is for |
|---|---|---|---|
| **1 tube** | 100% silicone, color-matched (100% silicone, kitchen and bath, mildew-resistant, 10.1 oz) | About 22 ft of joint at a 1/4″ bead: about 31 ft a tube, + 15% for tooling. | Flexible movement joint at walls and the tub. |
| **1 tube** | Caulk remover gel | Softens old silicone so it scrapes out clean; new silicone won’t stick to old. | Softens old silicone so it scrapes out; follow the label’s wait. |
| **1 bottle** | Isopropyl or denatured alcohol (isopropyl, 70% or stronger) | The last wipe: soap film and remover residue off so the new bead sticks. | The last wipe of the joint: takes off soap film and remover residue so the new caulk sticks. |
| **1 roll** | Painter’s tape 1.41″ × 60 yd (1 roll) | Two lines along every joint for a straight, clean bead. | Masks trim and ceilings. |

### 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.

## The steps, in order

> **DIY OK: you can do this yourself with standard tools.** About 2–3 hours of work for this example.

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.

## Tools (8)

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

| Tool | Need | Why |
|---|---|---|
| **Caulk gun** | **Must have** | A dripless gun |
| **Utility knife + blades** | **Must have** | Cuts the old caulk along both edges |
| **Caulk removal and smoothing tool set** | Good to have | Pulls the old bead and tools the new one |
| **Putty knife** | Good to have | Scrapes what’s left |
| **Heat gun** | Good to have | On low, softens stubborn old silicone |
| **Shop vac** | Good to have | Picks up the scraps |
| **Work gloves** | **Must have** | Tack strip, block and lumber shred hands. |
| **Safety glasses** | **Must have** | Every cut, every nail, every time. |

## Mistakes and how the math works

### 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.

## Code, permits and safety

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the [code reference](https://studsheet.com/codes) 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.

## Questions

### 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](https://app.studsheet.com/p/caulk) 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.

## Ask about it

Stuck while you re-caulk a tub or shower? Ask in the [Grout and caulk group](https://studsheet.com/forum/grout-and-caulk) 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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