Is "Tyvek" or equivalent an acceptable WRB behind panels?

“Tyvek” and similar plastic housewraps are fine as a weather-resistive barrier, but they are not a good surface for adhesive. Keep your WRB for code compliance and create a bondable face or rely on mechanical fastening.

Options That Work Well

• Add a bondable backer: install cement board or exterior-grade sheathing over the WRB so adhesive bonds to the backer, not the housewrap.
• Use a rainscreen: add furring strips over the WRB, then fasten panels mechanically to the furring and supplement with adhesive on the wood backer.
• Liquid-applied membrane: over sheathing, use a roll-on or trowel-on WRB that cures to a bondable surface, then install cement board if additional rigidity is needed.
• Self-adhered membranes: peel-and-stick WRBs may still be low-adhesion; treat them like plastic housewrap and add furring or cement board before adhering panels.
• Masonry substrate: where you have block or concrete, prep and bond directly to the masonry with adhesive and masonry screws.
• Mechanical-first installs: if an adhesive bond to the WRB is unavoidable, prioritize screws into framing or furring, then seal all penetrations.