Preformed roof ventilation system

23) A roof ventilation system for mounting between roof framing members and roof sheathing, comprising:

• a panel including:
• a) a roof side, an attic side, a first end and a second end;
• b) a vent trough formed from a first flanged lateral edge, a middle section and a second flanged lateral edge, wherein each said flanged lateral edge has a canted section, wherein each said flanged lateral edge has a flat edge section extending outward parallel to said middle section;
• and
• c) an array of vent channel supports dimensioned to extend from said middle section to a plane defined by said flat edge sections of said first and second flanged lateral edges, each said vent channel support intersecting the plane at a single apex.

26) An insulation dam for creating a barrier between attic space and eave space, the attic and eave space bounded by roof framing members and roof sheathing, said insulation dam comprising:

• a) a flat and rectangular top panel having a top edge, a bottom edge, a first top panel edge and second top panel edge, said top panel having a width that spans greater than the width between the roof framing members;
• b) a baffle flap having a top blocking edge and opposite frame edges, said blocking panel attached at said top blocking edge by a hinge to said bottom edge of said top panel;
• said blocking panel spanning the width between the roof framing members;
• c) a baffle flap tab extending from each of said opposite frame edges of said baffle flap, each said baffle flap tab having a fold line where it meets each said opposite frame edge, whereby when said insulation dame is installed each said baffle flap tab bends toward the eave space and orients to attach substantially parallel to the inside of the roof framing members;
• and
• d) a baffle flap gap between said top panel and each said baffle flap tab, said baffle flap gap dimensioned so that said baffle flap tabs do not stick into the plane of the roof sheathing when secured to the roof framing members.