Hi Chris. I like the colour scheme and materials for your house, although a few things come to mind. Why have two different timber finishes, Merbau and Western Red Cedar? Is Merbau not available as a garage panel? Or is Western Red Cedar not available as post cladding? If they are both available for both applications, I would choose one for both applications. You mention black Sikaflex as joint filler for the cladding, and off-White mortar for bricks. Would you consider black mortar for brickwork for consistency, or do you not like the look of it? I bring these questions up because there are a lot of materials, which is great, but maybe minimising the number of colours and using them more consistently would produce a more cohesive visual outcome. I googled images for brickwork and black Sikaflex and this is the only decent one I could find quickly - just to give you an idea of how it might look.

i'd want to know what's caused the damage, lack of maintenance, poor choice of original material or a more serious issue? A roof leak is such an important problem that i'd invest in advice from a professional (roofer, builder, carpenter and/or plumber) and ask them to check the whole roof inside and out including sarking and insulation, cladding, eaves, fascias, flashing and all the gutters and downpipes...unfortunately ignored problems will only become worse and create bigger issues..good luck with it

I just googled & found this site, which quotes cost of R2.5 75mm. there are other suppliers as well. What was quoted to you for cost of roof installation, and was it itemised so you can see exactly what thickness the foil-backed insulation builder will use? I'm guessing the thinner (lower R factor). So, the new quote should reflect a credit for the cost of previous insulation, since it won't be used, then cost of thicker insulation added. Does that make sense? If you are unsure, best to speak with the builder. https://www.pricewiseinsulation.com.au/product/heavy-duty-fletcher-permastop/

Hi Dr Retro, Thank you. I really appreciate the input and the time you've taken to explanation your point of view. I really do want to get an understanding of where the issues lie in this design. So I hope you'll forgive me digging a little deeper. I don't quite follow why you think the design would require a 6m lintel. Yes, it does require a 6m track, but the track can simply be attached to the wall. The weight of the door need not be supported by the top track. It could be supported from below. The whole point of putting the configuration on the outside of the wall is to minimize the need to make structural changes to the building. There currently is no capacity to install a 6m wide external sliding door/window unit. Likewise I don't follow why the door should be any draftier than any other external sliding doors. The cavity is on the outside of the wall, so draft is not going to get in via the cavity. Other sliding doors of the unit type have the same draft problems this configuration would and solve it by using an overlapping flange at the front end of the fixed door and the back end of the slider. The same could be applied here, where we treat the wall as the fixed door.The point at which the doors engage each other has also be solved for other door configurations. It is just a matter of having a loose tongue and groove configuration. Again this is exactly the same as a unit providing center opening sliding doors. Finally the same sliding mechanisms are used in other sliding door configurations, so I don't see why that should be any draftier here either.