Hi Brett, first off - well done for reaching out (without ego) and asking those that know and those that have tried and found results. If you are going with the brick veneer, the cavity is key to your moisture and thermal capabilities, after years within the house. Gyproc is not designed for anything but a 'skin'. If you increase thermal layer on the walls by asking he outer layer of the stud work with good quality silver sarking or Tyvek. Tape joints to eliminate vapour transfer to internal gyproc. Use 12.5mm gyproc on all external walls. OR Use 12.5 silver backed gyproc board on walls instead of previous. If coast effective -I would use this on the ceilings also. Principle being - isolate the internal breathing environment both thermally and other from the externals. Then deal with any ventilation or thermal issue by themselves internally. Look at why a house is designed, then go 100% better. The problem with roof voids is cold at night and heat in day, focus on high air barrier and high 'R' values here. Internally, consider + and -, as in, where it is cold-draw heat to it (South+ low) where it is hot, draw coolth to it (North & high). The result will be both continuos balance or equilibrium in comfort, thermally, energy and ventilation wise... Hope this helps : )

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once our homes are allowed to heat up it's very difficult to cool them down because heat from warm air allowed in through open windows and doors is stored in the walls and floors and then released back inside the house as the outdoor temperature drops ..this heat sink effect is fabulous when you have a good sunny day in cold climates but challenging when we have extended periods of hot weather and especially challenging in your hot climates where homes need to be lightweight to minimise this passive heating effect and outlook and orientation need to be different than most advice available about these effects (which is usually aimed at retaining heat in cold climates). We have ceilings fans and cross ventilation in all major rooms, high windows with electric openers to increase the stack exhaust effect, maximum insulation in roofs and walls, double glazed windows, insulated internal window coverings and solid internal doors to restrict heat movement, wide eaves and/or verandahs and have substituted more lawns,trees and gardens for some paving but windows on the eastern side still allow sun to heat the house from early morning and windows on the west increase the effect till late evening and we now plan to install adjustable vertical screens on the outside of windows and verandahs to increase shading.. living in a cold climate we already have heating but we are now considering upgrading our heaing to include reverse cycle air conditioning but we're hoping the new screens will avoid the ac..good luck with your challenges

This Two Storey house was designed by StudioMarioRenzi using Insulated Foam blocks and panels. We worked closely with the owners to get the most effective design. The simplified form of the external walls enabled them to construct the IFB walls by themselves. With our assistance we help them to construct a home that is very unique. Hats off to the two of them, they did a fantastic job! Internal view External view