Shower base/wall caulking

[Glwalters82]

I have a solid shower base and tiled walls. I have had the installer recaulk the gap between the shower base and tiled wall. It lasts about 6 months and then the caulk begins to crack and the water begins to get wicked up thru the crack. There is a rubber membrane between the cement board and the framing so the water is contained and does not leak onto the ceiling below. What does happen is the water will eventually migrate to the shower door side and leak out a gap there onto the floor. As I said, the new caulk remedies the leak but eventually the caulk begins to crack in that gap and the process starts all over again. What is he doing wrong?

 

[Jeff H Young]

cheap caulk? try another brand

 

[Sponsor]

 

[Jadnashua]

A square glob of caulk is not very strong...ideally, the shape of the caulk will end up more of an hourglass shape so it stretches easier without pulling the two outside edges off. To achieve that, try using some foam backer rod stuffed into the hole/crack first, then caulk over it. That stuff comes in various diameters to accommodate various sized gaps.

Basically, when you have a square chunk of somewhat flexible material like caulk, when it tries to stretch as things expand and contract, it's only relying on the bond strength to hold together and it tends to tear off one or the other edge. If you use backer rod, you create a thinner, much more flexible section in the middle, so when things expand, the stress on the bond is much smaller, and the thinner section can stretch rather than trying to stretch the whole block, leaving the outer edges intact, and bonded to the two surfaces...it also uses less caulk. Backer rod is cheap, a good caulk tends to be a lot more, too, and it will make it all last longer.