Owens Corning Extruded Polystyrene Fanfold Underlayment Foam Insulation 1/4" x 4' x 50' R-1

Owens Corning® fanfold underlayment board adds insulating power, eliminates gaps to reduce air infiltration, and provides a smooth nailing surface for re-siding exterior walls. This board is perforated to allow excess moisture to escape.