Roof insulation systems

An insulation system comprising:

• spaced apart wooden structural members;
• sheathing panels disposed on top of top surfaces of the wooden structural members;
• insulation support material comprising a first interconnecting portion and a second interconnecting portion, the first interconnecting portion and the second interconnecting portion are attached to the wooden structural members or sheathing panels from below the wooden structural members and sheathing panels, the first interconnecting portion and the second interconnecting portion each comprising a span segment, and each side panel segment that is connected to only one side panel segment;
• insulation disposed on the insulation support material, such that insulation is disposed directly under bottommost surfaces of the wooden structural members.

An insulation system comprising:

• spaced apart wooden structural members;
• sheathing panels disposed on top of top surfaces of the wooden structural members;
• insulation support material pieces attached to the wooden structural members or sheathing panels to define insulation cavities, the insulation support material pieces each comprising a first side panel segment, a second side panel segment, and a single span segment extending from the first side panel segment to the second side panel segment, wherein each of the insulation support material pieces further comprise a first tab at a junction between the span segment and the first side panel segment and a second tab at a junction between the span segment and the second side panel segment;
• and
• insulation disposed in the insulation cavities directly under bottommost surfaces of the wooden structural members;
• wherein at least one of the first tab and the second tab of a first insulation support material piece of the insulation support material pieces is connected to at least one of the first tab and the second tab of an adjacent insulation support material piece of the insulation support material pieces.