Cracking at interface between tile wall and bathtub

[Sukhoi]

I understand how tile walls naturally crack at changes in plane in our shitty American wood framed buildings due to soil movement and framing expansion/contraction due to seasonal/temperature changes. For a full tile shower one can caulk the corners between the walls and floor, as any moisture which gets through the wall grout can travel down and below the floor to the secondary drain inlet.

How does one deal with this with tile walls above a bathtub? Grout between the walls and tub cracks, but caulk will not allow trapped moisture to escape. Is there a flexible material to use for this purpose that won't crack but is permeable to allow moisture to escape the wall?

 

[Greenman]

I understand how tile walls naturally crack at changes in plane in our shitty American wood framed buildings due to soil movement and framing expansion/contraction due to seasonal/temperature changes. For a full tile shower one can caulk the corners between the walls and floor, as any moisture which gets through the wall grout can travel down and below the floor to the secondary drain inlet.

How does one deal with this with tile walls above a bathtub? Grout between the walls and tub cracks, but caulk will not allow trapped moisture to escape. Is there a flexible material to use for this purpose that won't crack but is permeable to allow moisture to escape the wall?

Use caulking. There isn't supposed to be enough moisture in there for it to be a concern. If there is, you have a second problem that needs to be addressed.

 

[highland145]

And mask it off for a nicer job.

 

[Sukhoi]

I see. Caulk it is.

 

[Scarpozzi]

Caulk....

Eventually, plan a remodel and address damage then if you notice any. If the tile's installed already, it'd be a tear out to fix it anyhow....look at everything surrounding the tub as cosmetic. I like fiberglass tubs myself with 1 piece alcove surrounds because water can't get trapped behind the walls as easily....just my preference.

 

[Sukhoi]

Oh this is for a pending remodel of our hall bath, which probably won't happen for another year unless I get stupidly motivated. Going to leave the existing tub in place.

 

[skyking]

I used sanded caulk that very closely matches the grout. Get the caulk from your grout manufacturer. That joint will always fail if you try and just grout it in.

 

[Humpy]

Caulk is best but most contractors don't use it correctly, it's just splooged in and smoothed off with a "caulk fixes everything" mentality. It still fails if there is significant movement.

First step is to control movement structurally. Then figure out what to do about the gaps.

 

[Greenman]

The crack between the tub and tile walls is pretty much a given. The tub and floor it's sitting on is going to flex as the tub is filled with water and a person. Since the walls aren't connected to the tub, there is always going to be some differential movement. The other issue is that grout doesn't stick to the tub surface very well.
Most tubs have a lip that is tiled over, so you could leave the grout out entirely and not have a leak. Mold would be the problem at that point.
Generally caulk has enough flex to span the gap and keep the interface sealed.