Gal will go grey (mid to dark grey) over 12 - 18 months. Initially VERY bright. The energy absorbed changes accordingly, from sub 5% absorbed to ~35%. Zinc maintains brightness for longer, though still suffers some dulling. Say 5% to 15% over time. This can be avoided by coating with a product called 'Sharkhide' metal protectant, used to stop aluminium boats oxidising. For there reasons many councils will not allow zinc or gal roofing (visual amenity, reflection issues), while making the houses more prone to requiring summer aircon at the same time. Surfmist Colorbond starts around 9% absorbed. If purely for energy reasons, a light colour might be the only option. If going dark, I would suggest at least doing the 'less aesthetically important' sides and rear in a light colour. Your call. If you go all dark, ensure you have good roof space ventilation for the summer that can be closed in the winter, and lots of well installed ceiling level insulation. Spray foam is more reliable over time than batts, see Spray It Solutions or similar (they have the Formaldahyde free Canadian Icenene foam).

We have a 1960 brick veneer, ours is a Colac brick with a fair amount of variation in the colour, more an overall light orange, with the brown terracotta roof tiles. Very funny as we have trades come to the door wanting to clean the tiles, I tell them I love the mossy look. We have the wooden windows painted with 'orange scent' (a creamy colour) and then added a heritage style pergola all along the front and side with grapevines and wisteria. posts and fretwork painted with 'Native grass' paint colour- softened it down and beautified the frontage wonderfully. When we did an extension we thought about rendering but decided to keep the brick look. We took 12 months to source new and old bricks to match the original- looks great.

Congratulations Mark! I really like the drawings that you did up with the new door and deck at the front. It makes a huge difference to the house. I think the all grass look at the front is a bit much. It would benefit from some sort of pathway to the deck, but I don't have the imagination of the other Houzzers, but I love what you have done so far.

HI All - for some reason my lengthy reply a few minutes ago was deleted :-(. I put so much thought into it! So here it goes again. Basically a big thank you to you Houzzers. MB your subfloor ventilation sounds great and Im glad it's fixing the problem so simply. The reason why Im trying for a whirligig solution is that I favour a passive system, however if it doesn't work I'll look into what you suggest Siriuskey - yes to some kind of kit. I've already contacted a guy on Gumtree selling grannykit frames - he says for something to my specifications would be about $4000 for the steel frame alone. Would need to check engineering details - and the liveable sheds you've linked me to seem to have that all checked. Although getting a local Chippie to frame it all up on site - as Twos Co suggests - is probably the most economical option Two's Co - thanks for the feedback and the excellent checklist of processes. I've covered most of the concerns though - I've got the DA based on my own flimsy plans. Because it's relatively small, I was going to work with the builder directly and over-engineer it. I've since engaged an architect to do some handsketches and draft specs, which will be signed off by a structural engineer. It's basically a portal frame independent structure, with a 3 degree pitch skillion roof. The house was rewired and the wires you can see are non-live looms waiting for the extension! The sewer is not connected and that part was never plumbed in. There's good rear lane access, but for the purposes of getting concrete in, I'll most likely get a concrete pump from the front of the house - for $180 per hour they will save time and make the concreting much easier. The existing trench I got dug in because I had an excavator on site installing those lovely large concrete blocks you can see, for the retaining wall (500kg each). But that was 7 weeks ago, and the excavation has got too large, and I worked out for a very similar cost I can make the extension 1m wider, so why not. The existing trench I can fill in with the demolition rubble, compact, and filled with any fill waste. Two's Company, I'm on the fence about removing the existing Bedroom 3. If I thought it wouldn't add to the costs too much, I'd do it. One advantage is that I could then make the whole 9m long extension (Option 2) around 150 - 300mm higher, (ie a step up from the existing house) and thus avoid too much excavation and a potential pond. To answer your question about damp and moisture, the whole house is facing a hill with 7 degree slope, and fixing this has been the main aim of the retaining wall, however the runoff is only likely to increase in coming years. anyway here are a few photos. The site is still so messy because the demolition only happened 2 days ago - Im still tidying up....