#1764: LoftLofting
Insulation material in a roofspace has a tendency to compress -especially if you want to use a double layer.
This greatly reduces the effectiveness of heat retention.
Today’s invention is a cheap plastic fork with needle-like tangs (red).
When the insulation is laid, and has had a chance to expand or ‘loft’, many of these forks would be pressed into the sides of each batte in order to maintain its thickness (and air retention) over time.
Comment by Patrick
A refinement of this I just thought up would be to make these items with a bimetallic element, so that, as as the temperature outside falls, so the vertical spacing between the tangs (and thus the air content within the insulation) increases.