Loose fill insulation in loft

[jono_h]

We’ve just moved into a new house and a quick an easy job to get started is to insulate the loft.

iIt currently has loose fill between the 8” joists - does this degrade making it worthwhile sticking new 200mm mineral wool between the joists and 100mm over. Or is it good forever and a bit of 100mm over the top would suffice?

Thanks,

 

[Alastairreid]

Unless it is paper mulch it doesn't even degrade in landfill. I would leave existing and upgrade to modern standards.