My house is a single storey brick veneer, 3 bed, construction built about 30 years ago. I did not expect that it would be almost entirely uninsulated.
Through observation, when exterior walls were opened from the inside there was no discernible insulation at all. In the roof space the 1"/2.5 cm (approx) rockwool insulation has been scattered by an invasion of possums (Now humanely ejected, or allowed to escape, after their access point was secured against movement!).
So the house cools quickly and heats quickly leaving the air-con puffing and panting to keep up with maintaining the temperature at temperate level and my electricity bill expanding whenever the middle of summer or winter arrives.
So, The ceiling insulation should not be too much of a problem. I've had a quote for a firm of professionals of $1750 to do the ceilings/roof space. But the walls are a different matter. There are a number of choices of which I am aware:-
1. Remove interior drywall Gyproc board, stuff the stud spaces with rockwool. Replace Drywall and redecorate.
2. Spray polyurethane foam into the spaces, via drillings through the drywall or brick veneer.
3. Introduce polystyrene beads into the cavities. (Polystyrene and pvc cable sheathing don't go well together as there is an un wanted interaction.
4. Blow small fluffy bits of rockwool into the cavity.
There may be other methods of which I am unaware but I'm looking for well considered advice.
Thanks, Clivev