We had small shower room refurbished 6 months ago, with old electric shower cubicle ripped out and new shower (running off combi boiler) with new sink basin and toilet. New backerboard and shower area was installed and tiled and grouted.
Tiles on lower half of wall then runs round entire room. Floor outside of shower was also re-tiled.
Had bigger fan installed but, due to small room, condensation/moisture in room still builds up a lot, a lot more so in colder weather.
As colder weather started, found water seeping (a slow drip) through ceiling below (through plasterboard join). It stopped after a few hours. I put a small hole at point of leak to stop water building up/ceiling sagging. Then tried shower and sink and toilet repeatedly and aiming at parts of shower wall but no further water leaked through.
4 days later, the same type of leak then occurred through the ceiling but at the other side of the room, along the same plasterboard join. Again, I pierced a small hole in the ceiling but that leak stopped within an hour or two and no further water has since come through.
I checked grouting and there were a few gaps (as dark grout, the builder said he had trouble seeing where he hadn't covered) but I saw a few gaps around the top which I have since filled in.
3 weeks later, we've had no further water come through the ceiling but now the grouting, where the wall (outside of shower) meets the floor, is permanently wet and the wet area is spreading along the bottom of the wall.
That wall is where the piping (for sink and shower) run through. The photo shows the damp grout along about one tiles width but this is now more like 2 tiles width a week or so later.
I think water or condensation may have got in behind the wall but, once the grouting is sorted, shouldn't the grouting have dried out?
I have noticed that, where the basin pipe goes into the wall, the opening in the wall is quite large and not blocked in/sealed off. Could condensation be running down that pipe into the wall? The sink pipe has that metal ring on it that I presume is meant to fix on to the wall where the pipe meets the opening but it's just hanging loosely on the pipe and wouldn't fill the gap between the edge of the hole/wall and the pipe anyway.
The shower tray, 10 cms away, seems to be siliconed well along the bottom and is over a ling of grout (which runs along where the wall tiles meet the tray). There is no caulk or silicone running along the corners of the wall and I wonder if this would help. There is just grouting along the corners.
Any input or suggestions would be greatly appreciated.
Stevo