DuPont (Tyvek, Styrofoam and Thermax)3. DuPont: weather barriers and rigid insulationGuides featuring DuPont (Tyvek, Styrofoam and Thermax)Building-Envelope Products for Calgary: 7 Brands and the Details That MatterCompare Calgary building-envelope products by insulation, membranes, moisture control, fire details and the wall assembly—not brand name alone.