Most everyone understands the need to caulk the long seams between the wall and the edges of a bathtub or shower pan, or along the rails of a shower door. But often overlooked are the smaller seams around escutcheon plates and the various rings or caps concealing the holes where plumbing pipes or faucet valves come through the wall. If these joints aren't caulked, water can easily get behind them and into the wall. And water in the wall can mean mold growth, rot, and even leaking into the ceiling or floor cavity below the shower or tub.
The best caulk to use in a shower is 100-percent silicone caulk designed for plumbing applications, often sold as tub-and-tile or kitchen-and-bath caulk. Silicone caulk has good adhesive properties and will not only seal cracks but also hold trim pieces to the wall. It's not a bad idea to get a caulk that includes a mildewcide to help prevent discoloration from mold, which is almost always present in bathrooms. You'll also want to give some thought to whether you'll want colored or clear caulk, a decision that usually depends on the caulk used in the rest of the shower area.
Although the caulk for this project is sold in full-size tubes for use with a caulk gun, for working with the relatively small spaces involved with tub trim, you might want to use caulk that comes in a squeeze tube instead.
Equipment / Tools
- Clean rags
- Putty knife (optional)
- Utility knife
- Bathroom cleaner
- 100 percent silicone caulk
Clean the Surfaces
Thoroughly clean the area you will caulk, using your preferred bathroom cleaner. Rinse the area and dry it with a clean rag. Caulk adheres best to a clean surface, so make sure the walls and trim are completely clean and dry. If you are replacing old caulking, remove all of the old caulk using your putty knife and clean the surface thoroughly.
Prepare the Caulk Tube
The secret to a neat application is cutting the right size opening on the applicator tip of the caulk tube. The lower down on the tube you cut, the larger the opening and resulting caulk bead.
For trim, a 1/4- to 3/8-inch bead is good. To cut the applicator tip, remove the cap (as applicable) and use a sharp utility knife to cut off the tip at a 45-degree angle. Some caulk tubes have markings on the tip indicating where to cut for various bead sizes.
The caulk will be easier to apply if it is slightly warm. You can warm the tube by holding it between your hands for a few minutes, or by soaking it in warm water before you cut the tip of the tube.
Place the applicator tip against the shower surface at a 45-degree angle. Apply a small, uniform bead of caulk all the way around each part of the shower trim. It is important to cover the whole seam because water can leak through even the smallest gap.
Shower and tub trim parts you should caulk include:
- Tub spout
- Faucet handle escutcheons
- Shower valve escutcheons
- Bathtub drain overflow plate
Caulking around the showerhead trim is optional, as this area usually isn't prone to much water intrusion. You can judge for yourself.
What is an Escutcheon?
An escutcheon is the (usually) round plate that fits around your shower fixtures such as the faucet or showerhead. Its purpose is both aesthetic and functional, as it covers up the holes through which your plumbing pipes run.
Smooth the Caulk Bead
Immediately after applying, use a wet finger (some people like to use a damp rag or a sponge) to smooth out each bead of caulk. Using warm water works best. The goal is to leave a small, neat bead that still fully covers the gaps around the trim. It is important to do this immediately; silicone caulk takes a long time to fully dry but can become less spreadable pretty quickly.
How much caulk is wiped away is up to personal preference. Some people like to leave fairly large caulk lines, but small, thin beads usually look better. A thin line of caulk is just as effective as a large one as long as there are no gaps. Keep in mind that a thicker caulk joint draws the eye, while a thin line will be less conspicuous.
Let the caulk cure as directed by the manufacturer. Silicone caulk usually must dry for 24 hours before it's ready for heavy water contact.
If you’ve used squeeze-tube caulk for this project, simply replace the cap to store it. If you used a caulk tube in a caulking gun, you’ll want to ensure the tip is sealed before storing. You can do this by wrapping plastic wrap around the tip and securing it with a rubber band, or squeezing a little caulk out and inserting a large nail or golf tee into the tip to form a plug. All caulk should be stored in an upright position.