Hi my loft was converted between 1980-1990, it is cold and noisy as we are adjacent to a busy road. I'm hoping to upgrade the insulation and plaster board to improve thermal and sound qualities room by room. The first room has 100mm rafters with 50mm glass wool to the vertical stud walls and sloping ceiling.
I understand that Celotex type insulation gives better thermal performance than wool but wool gives better sound insulation. I'm also limited to thickness between rafters to leave 50mm air gap.
I have also been looking at acoustic wool slab but I'm unsure if this is suitable for use between the rafters in the ceiling.
Also if i decide to overlay the rafters with Celotex and seal the joints for vapour barrier. What method is there for wall fixings?
Most importantly do I need building control for this?
Thank you.