The One Place That Should Never Be Caulked, But Often Is

This one location is commonly caulked in tiled bathrooms- but it shouldn't be. Learn what you might be doing wrong here.

This week on ‘Mythbusters’…

Everyone knows that it is important to keep the connections between a tub and its shower surround well-caulked.

Take a look at this first picture.  This is brand new construction- doesn’t it look great?  Don’t you wish you could lay a bead of caulk like that?

Very neat caulking at tub and wall connection

Before you get too envious (you knew this was coming) I am here to tell you that the caulk should not be there.

As commonplace as it may be -and as logical as it may seem- it is still wrong in many cases.  Caulking this connection is fine if the wall is some sort of one piece sheet or enclosure, but with tile it should not be there.  The grout joints are designed to prevent water from penetrating the wall, but any small amount that does penetrate is able to evaporate out and/or weep out along the bottom.

If the tub/tile connection is caulked, the water cannot wick out through the bottom grout joint, moisture builds up and is then able to feed the mold that eventually develops.  I am sure you have all seen that grey discolored staining of the caulk that you would swear is “behind” the caulk—-where it cannot be cleaned off. And you would be right—it is behind the caulk.

Mold behind the caulk at the tub and shower wall connection

If there is enough water building up behind this area, the water will run around the edge of the tub and down the walls behind the tiles “outside” the tub. This commonly results in damage to walls and floors outside of the tub.  Sometimes this damage is just from water not being corralled into the tub by the shower curtain, but if the same thing happens with a shower door in place, these other factors may be at play. These conditions can also “complicate” the inspector’s moisture meter readings.

So if you have a tile tub enclosure, keep the grout well repaired- but don’t caulk the connection. The enclosure will behave itself much better.

About the author

Reuben Saltzman is the owner and president of Structure Tech Home Inspections.