You may prefer not to “take things legally” but if the strata committee won’t play ball that is your next best option.
By asking them to fix what is to all intents and purposes a common property defect, and them refusing to do so without a by-law (which is NOT required, by the way) they trigger the provisions of section 232 (e) of the Act, namely “failure to exercise, a function conferred or imposed by or under this Act or the by-laws of a strata scheme.” The “function” in this case is the Owners Corps’s legal obligation to maintain and repair common property.
In 232(2) the Act defines failure to exercise as “an owners corporation [or] strata committee …. is taken not to have exercised a function if: (a) it decides not to exercise the function, or (b) application is made to it to exercise the function and it fails for 2 months after the making of the application to exercise the function in accordance with the application or to inform the applicant that it has decided not to exercise the function in accordance with the application.
So you have asked them to fix common property and they have effectively refused or failed to do so. Your next step MUST be to seek mediation at Fair Trading with a view to pursuing orders at NCAT. Perhaps that might sharpen their thinking.
If you are worried about putting noses out of joint, just tell the other committee members that you have had advice contrary to theirs and all you want is an independent referee.
Then sell them the insulation …