With the massive number of houses existing with this type of construction, I am astounded that no one is offering a retrofit of insulation to the outer walls. Must be a good reason, and I suspect it is cost (because of limited access), and/or condensation issues for the easier access "blow in" style treatments.
Investigation based on my own 1990 BV home, shows it had ZERO insulation, and NO sarking in roof or walls. Standard build then I believe, and I hope it has VASTLY improved since.
Roof - A previous owner had fitted some glass wool style insulation in the ceiling but it had deteriorated, as well as the ceiling was 10mm thick with dust and leaf litter blown in through the concrete tile roof (no sarking). No problem with ventilation of the roof space with a concrete tile roof, every tile has a gaps all round and it is incredible that they don't leak (mostly).
We had the ceiling vacuum cleaned and insulation replaced. Of course the dust is building up again (and I have a dust allergy!). I considered having all the tiles removed and sarking installed, tiles reinstalled or a metal roof replacement but the cost is prohibitive. $50k. Even doing it myself (slowly but surely) was just beyond my capability. And solar panels/solar hot water make the job even more difficult and expensive. So I just have to put up with the dusty space.
Walls - seems the options are few, short of demolishing the outer brick skin.
First option I am considering - selective striping of the Gyproc P/B off the inside walls, and installing some sort of rigid blocks of insulation (suggestions please?) within the studwork. Not a massive job as it can be done room by room, but very messy. I would cut the PB sheets a little way from the corners/ceiling to avoid disturbing cornice and corners and keep the plaster board repairs to straight forward PB jointing, using the original sheets if possible. I have replaced a few windows during kitchen/bathroom rennos, so I am aware of the battlefield. If I was going this way, I would probably replace the super thin glass sliding windows which are old/crappy/rattle and are of almost zero insulation value for heat and noise.
Option two - some sort of insulating sheeting on the outside over the brick, with render or facing like faux weatherboard. I have not looked at this option in depth. I think any potential condensation problem would be lessened with the insulation on the outside. What about the gaps top of wall into the eaves and so the ceiling space? Maybe the proposed wall insulation needs to be pushed up to meet the ceiling insulation.
Option three - the blow in style - filling the complete cavity. Cheapest, easiest if it is not subject to condensation issues, like mildew, mould and damp in the wall. I see some advertising hydrophobic glass wool style but I don't want to be the guinea pig.
Althom
