R Tech Insulation Foil In Or Out

My biased opinion is that xps is a better choice for exterior sheathing.
R tech insulation foil in or out. It is more water tolerant and more permeable although the r value is slightly less. An ideal radiant barrier has air space on both sides e g. Foil would go out but its insulation value is suspect.
What is the r value of insulfoam insulation. If there s no dead air space it doesn t matter which way the metallic side is facing. The metallic facer on insulfoam r tech may provide additional r value if it s facing a dead air space of 3 4 or more.
Insulating exterior walls with r tech insulation. To install foil insulation roll it out parallel to the ridge and cut it with a utility knife starting at the drip edge and working your way up. Overlap seams by about 3 inches.
The bottom line is that the styrofoam is going up with the foil facing the inside of the house and with the insulation slightly back so it creates a space between the foil covering and the inside of the sheetrock. Consider using insulating wall sheathing rather than wood sheathing products. Lay directly over trusses planks or subfloor and these large panels can fold out fanfold or be.
R tech has an average r value of about 3 9 per inch. Tacking it to the rafters under a hot roof.