water channel material the spacers 23 may advantageously be glued or otherwise adhered to one or both of the layers on either side thereof spacers 23 are made of a soft foam material which provides a self sealing barrier for water when nails screws or the like are driven through the spacers so as to mount the lath 20 to the wallboard 12 it will be understood that some of the foregoing elements need not be employed in the exact order shown in fig1 b and 2 the elements may be employed for example in the order shown in fig1 a note that one of the advantages of the present invention is that the construct of water channel material 14 spacers 23 and lath 20 with or without scrim 18 with or without vapor barrier can be provided as a unitary whole especially advantageous is to make the construct as a roll stock material so that a builder may simply unroll the amount desired and u201c cut to size u201d more or less fig3 shows a type of material 25 that could be used as a lath material in this application here it is a filamentous plastic having thin diameter elements 26 that run roughly parallel to one another which are joined by other elements 27 that cross therebetween the elements 26 27 having sufficient rigidity to be formed into a somewhat corrugated surface having peaks and valleys the material is open so as to receive plaster stucco or other cementitious or adhesive material therein and thereby serve the function.