We recently renovated our basement apartment and it all turned out beautifully... except for the shower. The floor is polished concrete and we had the concrete contractor slope the shower floor towards the drain so that we could keep the smooth concrete finish throughout the bathroom and avoid tiling.
Problem is the membrane wasn't installed under the concrete and tied to the drain as it should have been - a Schluter membrane was installed after the concrete was poured and framed, on top of the drywall just down to the floor. Now water is leaking through the grout, down the membrane, and pooling at the bottom and coming out the other side of the wall (the outside wall of the bathroom).
We thought the water might also be coming through the concrete floor so we taped up vapour barrier on the walls and now zero water is coming through, so it's obviously just the grout. The walls have been opened up and there is no plumbing leak.
We're not sure what to do at this point. We applied grout seal but it seems to be ineffective. We don't want to remove all of the tile and we certainly don't want to chip out our floor and reinstall the membrane.
Any suggestions? Perhaps we should use a better grout seal? Or replace all of the tile with something non-porous?
Any help would be greatly appreciated!