Ainsworth. Thermastrand radiant barrier roof sheathing features an aluminum foil overlaid on micro-perforated OSB panels. The foil blocks up to 97% of the sun’s radiant energy, and the perforations control humidity buildup in the attic, the company says. According to the firm, the panels are twice as permeable as commodity OSB. The panels are Energy Star–certified and also carry certifications from SFI and/or the Canadian Standards Association. 604.661.3200.