Fanfold Underlayment - GreenGuard P Series

When you need fundamental performance in an extruded polystyrene (XPS) siding underlayment, choose the P Series. Flexible plastic facers on both sides enhance durability, while an optional reflective facer enhances thermal performance. Both types of facers are perforated to allow moisture vapor to escape. A cut-and-fold hinge design ensures the underlayment lays flat.