Remove old insulation or lay new on top?

After a second opinion.....

Recently I accessed the Solar hot water fed rebate so now no longer eligible for the $1600 insulation rebate. So instead I am planning on getting the NSW $300 rebate before it runs out at the end of the month.

I've bought my new R3 insulation (South Sydney) and I'm wondering whether I should remove the old insulation first. It doesn't say that I have to, also the rebate is based on adding at least R3 and it doesn't have to be installed by a professional though it does ask you to state that you have installed it as per the relevant standard.

Anyway, here are my options;

1. Leave old insulation in place - it is that awful blown in stuff that started white, now looks an awful dark grey from years of dust and is flat as a pancake. I would lay the new stuff on top as is.

2. Suck out old insulation with a garden vac - it would kill a domestic vac but I reasoned that given long enough I could suck it all up into bags - trouble is I could be stirring up all kind of nasties and it will be a @@@@@ job. Where do I get rid of it all?

3. Pay someone $500odd (maybe more now if people are madly getting rid of old stuff for the $1600 rebate) and sit back in the garden with a cool ale.

I'm thinking 1?


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