Cost of insulation?

Currently got a quote from a builder.
For a single storey 250 sqm living area they ask.
R2.5 to R4.0 upgrade price 2,900
R2.5 to R6.0 upgrade price 5,500

both are way too expensive imo, what's your thoughts?
Looking at other posts and costs I was more expecting something like this:
R2.5 to R4 upgrade: 600
R2.5 to R6 upgrade: 2,000

Anyone experience with similar upgrade?
Just wondering if it's worth the 5.5 K cost...

hello
I asked if the builder can put insulation in the alfresco area, they asked for $2,500


how much is it to do the house after handover?

Those prices seem high to me too. I have been referring to Bradford's online calculator which enables you to find out how many packs of batts of a particular size you need for a given ceiling area, then multiplying that by advertised prices. Since the labour cost would not change, I would think the price for the upgrade would be the cost of the R4 batts minus cost of R2.5, which should be nothing like $2900. Very hard to explain. I would be very tempted to just buy some more batts later and put them on top of the 2.5 ones. In my ceiling there were existing pink batts and I just put some concertina foil batts on top of them for extra insulation. Foil batts are light and easy to handle; apparently you get an extra R1 down (summer) but only R0.5 up (winter).

Thanks for that.
Though to do an extra layer afterwards, but read somewhere that that the effect of that is minimal vs doing it in 1 layer.
Not sure on the rationale behind though

went to bunnings to check price of material
R2.5 would come to 1200
R4 would come to 1800
R6 would come to 3800 so that would give a 2600 upgrade cost at bunnigs prices, but assume they can buy it cheaper.
Still 2.6K vs 5.5K, that's double.

So you could buy R6 batts and install yourself, for less than the price of the upgrade, and probably sell the R2.5 cheaply on gumtree. Just pop them in large garbage bags and someone would surely take them off your hands. I'd love to know how the builder justifies that price gouge.

for us (based on 46sqm dbl storey) it was:

R2.7 acoustic batts ILO of standard batts to all external frame - $3700
R2.7 acoustic batts to all internal frames - $5100
R2.7 acoustic batts between first/bottom floor - $3600
R2 standard batts to R6 upgrade to entire roof - $1000

not cheap...

btw, you will find from research papers that there is no significant difference from R2.5 -> R6. (e.g. waste of money) in terms of reducing house temps, the difference in energy savings is about $200ish/year.

If you really want sound reduction/temps the way forward is ACOUSTIC BATTS.

Many builders don't allow R6 batts between timber frames because it's too thick. I'm surprise your builder is accommodating it..

Thanks for your inputs.



may I ask you how many sqm your roof area is?

Hi Baksteen, just recently asked our builder for multiple prices for insulation to achieve 6 star energy rating for our new house yet to be build. Based on a single story approx 25 sqs
Currently I have upgraded to R2.5 for $1350 in lieu of Standard, which is "Cellulose or thermal wool insulation to ceiling cavity" (meaning it's the loose insulation fibres that's pumped into your ceiling cavity) other prices given are as follow:
Provide fibreglass batts R4.0 to ceiling in lieu of Std $1450
Provide fibreglass batts R5.0 to ceiling in lieu of Std $2290
Provide fibreglass batts R6.0 to ceiling in lieu of Std $2690
DH and I are looking to upgrading again to R4.0 rating, do you think it's a waste of money??

Thanks for all your replies.
Really helped me to get a clear idea.
The builder has agreed to reduce the price to reasonable level.

Why not investigate spray foam? I know they say the outlay is quite expensive but according to their sites once it's on, it lasts. I have it on my list to investigate when I'm ready to build but that's 2 years away.