Old post but thought I'd update. We have finally moved into our forever home and on occasions, obviously in winter, we still have crying window (sob). We have the wet windows on the south side of the home which is the shady side so not unexpected but also on the north side where we still get lovely warm winter sunlight streaming in and I still do have all my windows slightly cracked open and it does help. Incidentally I have glass bricks in our bathroom on the south side and there is no condensation on this window at all. Our home has insulation in both the exterior and interior walls and we have double insulation in our roof, so factor 7 unlike the usual factor 3.5 not that it probably has any bearing on the moisture issue. We have a 1.8mtr wide veranda surrounding the entire home so the windows are some what protected from the elements but when the temperature gets fairly low and can be almost zero in winter, it seems impossible to prevent this crying window sindrome but I can live with the fact it is fairly easy and quick to remove with a Karcher window vac now, brilliant little machine at $99 and it only takes a few minutes. We have an exhaust fan in both bathrooms that is vented outside so the moist air does not go into the roof space and in fact even my rangehood ducting is vented outside too!! We even had condensation in the roof cavity as well to the point of having a rainforest up there but since fitting another whirlie into the roof making it three in total now, it appears to have almost entirely eradicated that problem. I can say catagorically now that crying windows are a very difficult problem to eradicate in very cold climates where obviously the inside of the home being heated at night is going to create the perfect conditions for the condensation to settle with the inside being far wamer than the outside and there in lies the problem which canot be changed. I have blinds and curtains that I close ever day before dark but it makes no difference. As I have aluminium windows and doors throughout, so no timber anywhere, it isn't such an issue for damage but annoying none the less but life goes on and I do so love my beautiful new home!!

You know, Alipetecampbell, I think a lot of good could be done by simply not allowing houses to be built unless they're designed by a qualified architect and signed off by a qualified engineer, and built to minimum standards that ensure proper passive climate control (insulation, glazing, orientation etc.) and social linkage issues - let's ban the food desert and the nappy valley. Developers have a vested interest in building cheap, and those rubbish houses sell because (a) there's not much else on the market and (b) superficially they look okay. You'd argue that what I'm proposing would raise housing costs, but let's stop making billionaires of developers, let's stop councils from charging silly money for planning fees (eminently doable if housing is professionally designed) and, as I have said above, use less land for more housing AND more greenspace too, and the cuts in cost these measures would create could go towards making all houses better.

Have you had the gyprock wall tested with a moisture meter, because this really looks like a recurring moisture problem where it wicks from one location to another, and that can never be repaired really successfully. Was the wall material replaced with a proper cement backer board used for tiling purposes. It this room colder than surrounding rooms and is condensation occurring within the wall cavity? Could there be pipe work within this wall cavity that is leaking slowly. A builder with an ophthalmoscope could perform a cavity inspection, alternately a builder with a heat sensitive camera could identify possible cold areas within the wall where condensation could occur.

You need to do as Wuff advises - also check that there's no water coming in from above (if it's failed, it's time to think about a bathroom reno or partial reno) - if this is Ok then definately get your exhaust fan serviced or replaced (get the most efficient you can and one that can be programmed for a delayed turn-off) and then hit the entire bathroom in a bit of a cleaning frenzy. I can see that you've got sections of grout coming out - it's also worth re-grouting (horrible job) - just make sure that you remove all the grout before applying fresh grout. I find that hot water, white vinegar (equal parts) and a half a cup of rubbing alcohol with a few drops of dishwashing detergent work a treat in any space but particularly where there's any porous surfaces (make sure you use rubber gloves - it's pretty harsh on your hands) - just replenish your solution when it starts getting grubby and cold - the alcohol and vinegar kill the mould spores, and the water and dishwashing provides general washing assistance. (Bleach will take the black colouring from mould but wont kill it completely in porous surfaces such as grout so use bleach afterward if the vinegar and alcohol don't work). Make sure that you dry out the area fully - if you've got a dehumidifier now's the time to use it. Going forward, get a glass squeegee and use it to get rid of excess water after you've used your shower - also cut down on the amount of steam generated if you can. You can also make a homemade bathroom cleaner (3 parts water, 1 part rubbing alcohol, 1 part vinegar a small dash of dishwashing detergent and 15-20 drops of teatree oil) spray it down and use bicarb of soda sprinkled on a cloth to clean down your tiles, tub and grout.