An insulation system includes roof sheathing panels, spaced apart structural members, a first insulation material, and a second insulation material. The first insulation material is disposed between pairs of the spaced apart structural members. The second insulation material is disposed across the spaced apart structural members and the first insulation material, such that both the spaced apart structural members and the first insulation material are covered by the second insulation material.

An insulation system includes roof sheathing panels, spaced apart structural members, a plurality of pins, insulation support material, and insulation. The plurality of pins are secured to the roof sheathing panels, the structural members, or both. The insulation support material is connected to the pins to form an insulation cavity below the roof sheathing panels and below the structural members. Insulation is disposed on the insulation support material, between the spaced apart structural members and directly under the bottommost surfaces of the structural members.

A thermal bridge-free insulation assembly may include hangers to support insulation in an attic. The hanger may include an axis, a proximal end coupled to a rafter, and a distal end coupled to a barrier. The hanger also may include at least two components that are axially movable relative to each other to selectively adjust a depth of an insulation space.

Building insulations, building insulations systems, and related methods are provided. A building insulation can include an insulation body having a bottom surface and a top surface. The insulation body can be configured to reduce conduction of heat through the insulation body. The building insulation can include a facing secured to the bottom surface of the insulation body. Further, the building insulation can include a plurality of reinforcing straps secured between the facing and the bottom surface of the insulation body. The reinforcing straps is spaced apart from one another and provide reinforcing strength for attachment of the building insulation to a building.

An insulation system includes insulation support wires connected to wooden structural members that support roof sheathing. Insulation batts are disposed between the wooden structural members and on the insulation support wire. Portions of the insulation batts are disposed directly under bottommost surfaces of the wooden structural members.