We have about 220m2 floor and ceiling space to insulate. House is 1960s, external walls are now all insulated.
There are existing ceiling batts, but these aren't very thick. I was planning to put a blanket over these. Knauf R3.6 "earthwool" blankets seem to be reasonable value, at a shade over $10/m2 incl GST. We have no downlights to bother about, access is good. Installing blanket form insulation over the lot should be easy.
There is existing foil under the floor joists. I'm ripping it down - while I think it might have had some effect (I wonder though if it's partly placebo effect) it's unsightly and dangerous (potential electrical hazard) and interferes with wifi and mobile phone signals. Joist spacing is about 360mm, access is good - sub-floor basement area is used for storage etc. Plenty of wiring (all PVC) clipped on the side of joists. Expol have a tape to put over wires to prevent plasticiser leaching in to the polystyrene, but there would be a hell of a lot of taping to do - unless when I get the foil down, I find that the wires are clipped toward the bottom of the joists, so will not be in contact with the polystyrene (60mm thick - and positioned up against flooring with no gap. I wionder though if some other form of insulation might be better - given that apart from the close joist spacing - installation should be very easy because of the good access. Retail price of Expol also seems high to me for what it is.
Any suggestions welcome. Online calculators suggest that this would cost about $8k to have installed rather than DIY. That seems to be a ludicrous sum given the ease of access.