I recently purchased a house that had some drywall damage next to the shower/tub. We could see there was a crack in the calking, figured we'd get that fixed and then fix the drywall, no issue. Well we did both, calking inside and outside of the shower area, but there is still water leaking into the drywall, I can't figure out where from. Drywall leak is about 2x4 inches. Any similar experiences out there?
This is a guess as the links to pics are still not working.
Most drywall moisture issues around tubs come from the seal between the tile wall and the tub edge. This is often a source of water that flows behind the tile and down over the outer edge of the tub. It is a minor amount and doesn't manifest itself until time has allowed enough water for the drywall damage to be evident.
Obviously the cure is to be sure there is a good seal at the tile/tub edge. Often the grout or old caulk needs to be scraped out and new caulk or color matching ceramic tile caulk used to seal the edge.
The other issue could be water just running over the edge of the tub and getting on the wall. However this is usually evident by a small pool of water on the floor at the corner of the wall and tub. The water could be very slight and not pool because it is absorbed by the drywall. ( Unusual, but encountered by myself in the past.) This issue can be cured by installing Corner splash guards.
Finally what you may be required to do is to observe what is actually happening while someone is in the shower using it. (Just running the shower will not create the exact conditions.) Have a good flashlight and a willing partner and be able to crouch down in that area of concern.
