joynz

From https://www.consumer.vic.gov.au/housing/building-and-renovating/checklists/implied-warranties-and-domestic-building-insurance ’Your builder or tradesperson must provide you with a copy of the policy and a certificate of insurance covering your property before you pay a deposit or any other money.’

Filling the gap keeps wind out and heat / cold in. You only get one chance so make the most of it! On one window I used a ‘low expansion’ expansion foam - but it was quite expensive. So on some other windows I used insulation scraps. On some other gaps I used foam (either the extruded foam that comes in a long tube shape - or grey foam expansion joint, cut slightly oversize and squeezed in the gap.

Use no more gaps.

Woolcell isn’t pure wool - it is a mix of wool, paper and borax. How will the paper cope with the dampness? The moisture also might have been wind-driven rain coming through the tiles rather than condensation. What R value of insulation are you planning to have pumped in? An online search shows that fiberglass can retain its R value after being wet as long as it hasn’t lost volume (thickness). A bit of damp might be OK - as long as it dries out and the R value isn’t lost.

But what happens when the new insulation gets wet? You are just moving the deck chairs … and wasting the value of the existing insulation (if letting it dry out might restore its effectiveness). If the insulation really is getting damp, then find out how deep the moisture is going before setting off on the same pathway with different batts…

Usually condensation inside roofs (that aren’t leaking) is due to warm inside air hitting the cooler underside of a roof (it happens on metal roofs too). This is common in the evening as the outside air cools and the warmer air in the roof hits a cooler roof surface. The good news is that tiled roof spaces without sarking are more breezy than sarked metal or tiled roofs so condensation should dry out more quickly. But don’t add insulation on top of damp insulation!

Is the person you spoke t a roof plumber? If not, get some advice from someone qualified. I think the comment you got about concrete tiles is pretty suspect. Sounds like a leak. Or maybe steam condensation. Is the roof lined with sarking? Is all the insulation damp - over the whole roof space or just in a few spots? How deep is the dampness? It’s a good idea to layer the insulation. But don’t cover the framing completely - so people can still see where to put their feet! But...