Love the white windows. We've nearly finished a major renovation of a 1950s Queenslander-esque house, and we agonised over the colour scheme. We found ourselves driving around the suburbs snapping photos of colour schemes we liked, and then analysed what it was we liked about each. We especially liked the look of white windows with medium coloured walls, and then a darker trim. We're thrilled with our final choices, which were Zincalume roof (shiny silver in colour), chamferboards in Dune (Colorbond colour - mid beige with a hint of grey), which really made our white windows pop. Gutters, hand rails and timber battens around base of house in Deep Ocean (Colorbond colour), a dark blue. Garage door and front door are white. Greys would also look great, a mid colour for your chamferboards, and darker for the gutters, lower half of the house and trim. Whatever colour scheme you settle on, I would especially focus on replacing or disguising the white wall material around the lower half of the house. A darker colour is more traditional, as are battens. Even painting the existing white walls will make a big difference. In the photo I've added, rendered fence and garage door surround are still to be painted Dune, white picket fence panels to be added. Due to a sloping block, battens around stumps are only visible from the sides and back of house. Click on the photo to see more of the roof/ paint scheme. This pic was one hubby took to show me the driveway the day it was poured.

I think go for wood and keep it traditional. I think they use cedar for steam rooms normally. They may cost more initially but will function better for the purpose... with polycarbonate sheeting you will have the constant run off growing mould and mildew and the cleaning and maintenance will be difficult. Timber will expand and contract with the changes in humidity and temperature and then breathe and dry out well afterwards. It will also look way better. Just make sure the timber is not treated.

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.

When our building company architect had drawn up the plans and we'd gone on to the next stage of "add-ons", we requested a niche in the tiled shower area for shampoos etc, but were told it can't be done due to water-tight issues. Then, during the walk-through before signing off, we mentioned this to the building supervisor, and he was surprised about our request of a shelf being declined, and said that we should've asked them before they tiled. But, since we'd already made quite a few changes to the standard plan, we didn't want to cause any aggro. Now we have one of those metal extendable corner shelves. So, it pays to get a second opinion.