Ultratherm from GUTEX
GUTEX Ultratherm is a roof insulation product with tongue and groove edges that creates a rain and wind-tight system. It is made from 95% softwood fibers, mixed with polyurethane binder and protected by paraffin wax. Unlike rigid foam insulation made from extruded polystyrene (XPS), low density fiberboard (LDF) is renewable, biodegradable, vapor diffusion permeable, and can be carbon negative.