Torn roof insulation - cause?

I was in the attic of my house today to install a satellite dish and was shocked when I saw the condition of the roof insulation. In several insulation mats, there were holes with pieces of mineral wool hanging out. It looked as if an animal had wreaked havoc up there. What could this be and how can I stop it?

Questionable whether there was an animal; mineral fibers are not suitable food for any animal. But it is possible that an animal overwintered in the fibers. However, I then wonder if nothing is noticed of this in the attic. Look for traces; droppings, tracks, food storage... if you have found something, you can search the internet for the appropriate animal - including deterrent methods.

Hello Olli, I know what you’re describing from my own experience. You most likely have a marten on the roof. Those beasts just bite into the insulation for fun and eventually ruin everything. You absolutely have to close all roof hatches and make sure your roof fits well with the house wall. The martens use the smallest gaps to get into the attic. If you seal everything up, the problem will resolve itself.

If martens have nested in a roof, the holes or tubes apparently serve as access routes. But holes in the insulation are only a sign that martens might be in the roof; since martens eat their prey in the den, one would have to discover feeding residues, smell, feces, urine stains. I think that would have been the first thing Olli would have noticed – especially the smell. As already said, just look for traces.