HI again! I've spent the past few days visiting far flung industrial estates to look at where the CarbonLite product is manufactured and my friend's double/triple glazing factory. (I, too, am more comfortable with the panelised wall/floor/roof systems than modular, after visiting the Modscape factory...which was very impressive but ...not for me). On my travels I was a bit disappointed to find that the CarbonLite walls in the factory, ready to go out for construction, were not made with the 'recycled PET bottle' insulative layer but with glass wool batts. Also, some of my queries couldn't be addressed due to a lack of technical knowledge on behalf of the person I made a time to speak to at the factory. The fellow I spoke to the day before, who has a potentially rival business, was extremely knowledgeable and I'm hoping to work with him towards costing our house, which is still in the design phase. Our site has excellent views to the south east which is what got me thinking about triple glazed windows and now I have fallen down this rabbit hole of new ways of thinking... Nevertheless, I have become much more interested in the Passive House concept and intend exploring further to see if 1. we will be able to afford it 2. if we can find a skilled, Passive House certified builder for South Gippsland and, 3. if we can work out whether it is just a bit of a fad that may be overkill in Australia! Do you think Passive House is here to stay? I'm trying to reconcile the passive solar/passive house principles- I've been so bound to the idea of thermal mass it's a hard one to let go of! However, i do prefer not to live on a concrete floor! Having just read 'dreamer's' link I think I may have been bedazzled by the triple glazing fairy dust rather than our reality of not being millionaires! Habitech looks interesting but I think it comes with the external cladding and i don't love the versions I've seen so far... I am completely in agreement with you regarding designing a house with the space you need rather than building some voluminous thing with space to burn, just for the sake of it! Ridiculous and irresponsible on a planet that is already using up far more resources than is sustainable over the not-much-longer term.

I am undertaking a Reno in Baulkham Hills. will require structural timber and cladding (JH Scyon or equivalent) i am guessing Bunnings is not cheapest! thoughts on auctions? other options?

check with local council if there's some underground sewerage pipes or similar (take your photos and /or ask for their building inspector to check it out...and/or ask a plumber if it may be something related to old sewerage or drainage on the block of land.. we discovered an old well on one property and the solution was to fill the hole with rubble and then we were able to cover it over but dont mess with something until you identify exactly what it is

For the small amount of range hood that would be in contact with the undulating subway tiles, I do not see a problem.