Unfortunately, the builder could not use the roof insulation he wanted to as it would have taken time for building regs to approve. He wanted to use a new material that acts like a blanket. It’s supposed to cover more areas as it can be tucked into small gaps. We opted to use what was originally planned. It’s like polyester. A bit more trickier to cut up and place in all the gaps. Still works well though and gaps can be a good thing for ventilation. Shouldn’t be an issue. I hope.