Attic: Replacing insulation to create a floor.

Picaresque

Hi,

I am looking at using my attic for storage.
I currently have a big layer of insulation roll sitting on the top of the joist and I would like to add insulation and floor to be able to store stuff. The joist are 120mm high.

• How tick can I go? 100mm?
• What would be the best equivalent? Hard Pir Insulation? Kingspan Thermapitch? Rockwool floor, which is a bit more flexible?
• Would I lose much compare to the insultation roll?
• Would I need a vapour membrane?

For the floor, I guess I would go for some loft boards?

Thanks

dathi

https://mybuildingsupplies.ie/shop/building-supplies/sheet-materials/osb-boards-sheeting/loft-legs-12-per-box-600mm-centres/?utm_source=googleads&utm_campaign=20374944233&utm_medium=cpc&utm_content=&utm_term=&gad_source=1&gclid=Cj0KCQjw7ZO0BhDYARIsAFttkCiOoiq8R8M3lY57OWEuH6Ilp_SrqUHKAS-J1G-hIt784GIB9N6B9skaAtPbEALw_wcB

loft legs like above