. This is most evident where gang nail trusses and ceiling battens are used.

Because fibreglass segments, polystyrene boards and other types of roll out blanket insulations sit on top of the ceiling battens, air ducting occurs allowing the heat to travel under the insulation to weak points or a gap next to the bottom cord of the truss where it escapes into the roof cavity to be lost forever.

The Building Research Association of New Zealand in their report "A Construction Guide to Home Insulation" state that a 1% gap in the ceiling insulation can mean a reduction in the thermal resistance level (R value) of more than 50%. This means that often a new home, although insulated, can in fact have an R value lower than the compulsory government requirement.

Insulation with fibreglass segments

INSUL-FLUF seals under the bottom cord of the gang nail truss, and sits snugly beside the ceiling battens onto the ceiling lining. Preventing completely any heat loss through ducting or transfer through gaps, thereby maintaining the R value, and reducing energy costs.