OP
rocker
Just feel through the insulation for the first joist, and crawl it. Cut through the insulation where you need, bish bash bosh. I'd wear a mask, and be prepared for an itchy evening - it's not the end of the world. Don't know how long you've been doing this, mate, but you're going to have to get used to putting faith in the idea that the joist should be there.....