Dark Lines in the Shower Caulk

The line where the tub meets the tile goes dark, or the vertical corners do, and it looks worse after a steamy week. Caulk is a soft joint doing a hard job. It gets splashed every day. If the room never dries, the joint stays damp and it stains. Sometimes the stain is on the surface. Sometimes the caulk has cracked and water is getting past it. Those are different levels of effort, and paint-on "caulk renew" products skip the difference.

Start with the room, not the knife. Fan that passes a tissue test, duct to the outdoors, 20 to 30 minutes after showers, curtain spread to dry. A joint you recaulk in a room that stays foggy will look tired again. Wipe standing water off the ledge. A squeegee is more relevant than a new color of caulk.

Look at the joint in dry light, after the shower has been off for a while. Is the darkness a film you can clean from hard caulk that is still stuck and continuous? Or is the caulk cracked, pulling away, gummy, or missing in stretches? Film on sound caulk can be cleaned with one bathroom product, fan on, no mixing of cleaners, then dried. Failed caulk needs to come out before new caulk goes down. New caulk over loose old caulk peels, and it can trap water you just tried to exclude.

If the wall above the joint is soft, the tile sounds hollow in a way that is new, or the ceiling below a tub has a stain, stop. Water is not a surface film anymore. That is a licensed pro, because the repair may be behind the tile, not in the bead.

Removing a small run of failed caulk is ordinary for some people and a mess for others. If you do it, let the joint dry before you apply anything new. Follow the new product's own time for water. Do not fill a wet crack because you have company tomorrow. If you do not want to cut near a tub, hire the bead. It is a short job when the wall is sound.

Skip the spray that claims to bleach a joint you have not dried. You may lighten a stain for a week and leave the crack. Skip painting the caulk. It will flake in the splash.

Write sound or failed, and whether the room clears. Then clean, or replace the bead, or call someone for the wall. One of those three. Not all of them in one afternoon.

After the joint is dry and the room can clear steam, look at the corners once a week while you are already in there. A new gap at the tub edge is easier to fix when it is a gap, not when it is a soft wall. Run a dry finger along the bead. If it catches on a split, that is the week to recaulk or to call, not next season.

Keep the fan in the habit even after the line looks better. People recaulk, admire the clean joint, and go back to shutting the fan off with the water. The new bead then lives the same wet life as the old one. The picture you want in a month is a dull, intact line in a room that is not foggy at bedtime.

If you rent, cleaning sound caulk and reporting failed caulk with a photo is a fair split. You can dry the room every day without owning the tile. The photo of a pulling joint is a clearer request than a complaint that the shower looks old.

This is a house check, not a diagnosis. Symptoms go to a doctor, and big wet repairs go to a licensed pro.

Caulk and the steam that ruins it are pictured in When Your House Doesn't Feel Right. $2.99 at https://clearnestair.com/book.