How should I insulate my walls in a brick veneer house that is 30 years old?

[CliveV]

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

[JacobZ]

Hi @CliveV,

Thank you for your question about insulating your home.

To start with, I would rule out options 2 and 3. Expanding foam does not provide a good level of R-value and is designed to be a filler more than an insulator. Polystyrene beads should be ruled out as they are not safe for use around electrical cables as they pose a significant fire risk.

Option 4 is likely less intrusive, but I expect it is not something that can be done easily and would require the assistance of a professional. There are also no guarantees that the insulation will penetrate all the areas it needs to.

The best option I see is to remove the plasterboard, fill the cavities with high R-value insulation batts, then attach new plasterboard and finish.

Allow me to tag @Nailbag, @Dave-1 and @Noyade for their thoughts.

Let me know what you think.

Jacob

[Dave-1]

Afternoon @CliveV 

I have a brick verneer home as well, shocking insulation that is half missing in the ceiling space also. 

Out of the options you have suggested the only one that really would raise the R rating would be to remove the plaster and insulate then redo the plaster.  That is a large amount of effort. 

Maybe see how the house handles the heat/cool cycle once you have the ceiling insulation replaced. Then work through installing insulation within the walls that face the sun in summer first?

I have shade covering parts of my walls during summer and it does make a difference. Winter the trees are deciduios. Maybe investigate diffusing the heat hitting the side of the house with timber slats or shade of some kind?

Dave

[Nailbag]

Hi @CliveV 

I would agree with @JacobZ feedback on all points. The only other alternative if possible would be to plant established trees in front of the outside wall. This would have a significant impact on insulation properties. 

Nailbag