I can feel the hate mail coming my way already but I am reliably informed that waterproofing roofs is the new embedded networks when it comes to scams, rip-offs and egregious over-servicing.
The myth propogated by some firms is that it is illegal to do a partial repair on a roof’s waterproofing and you have to do the whole area in one hit (very convenient for the contractor!).
However, I have spoken to some very senior people at the Building Commission who have told me this is BS and have heard from other buildings that as long as partial repairs don’t overlap then it is perfectly legal to patch waterproofing, as long as the patches are guranteed.
My own strata committee has been sucked in by this nonsense and, of course, since they are never wrong about anything, we are headed for a bill almost double yours and rising with every estimate.
My advice would be to contact the Owners Corporation Network (OCN.org.au) to see where they sit on this. And contact some other contractors and ask them a simple question first – “do you patch waterproofing on apartment block roofs” and if they say no, move on to the next one on the list.
By the way, there may be circumstances where a whole-roof re-waterproofing is the only solution. But it doesn’t apply to every situation and the excuse that they can’t get insurance has alarm bells ringing for me.