What is this type of roof membrane and how do i insulate roof wit Information, help and tips on many areas of roofing including trusses, tiling, venting, insulation etc....

[grant452]

We want to insulate our lean to so as to make it a liveable room.
Can someone tell me what the roof waterproofing membrane is in the attached picture and is it ok to put sheet insulation under it? In addition, what should I do with regards to ventilation as I hear some people say I need to have a 25mm gap between the membrane and the sheet insulation but do I need to do anything else?
Thanks for any advice given.

[grant452]

9B98EF56-A12F-42C7-87BB-80B1894BBF4F.jpeg

Apologies, attached is the image

[greenshieldroofing]

Batt blanket insulation is perhaps the most common type of roof and attic insulation. Though mineral wool insulation batts make a comeback, these rolls are typically made of fibreglass and are among the most affordable insulation materials.