Base for turf system with vertical support extensions at panel edges

Abstract

An underlayment layer is configured to support an artificial turf assembly. The underlayment layer comprises plurality of panels, each panel comprising a core with a top side and a bottom side. The top side has a plurality of top projections. The top projections form top side water drainage channels. The panels have edges, with the edges of one panel abutting the edges of adjacent panels, thereby forming a drainage path between adjacent panels. The panel edges have vertical support extensions that extend into the drainage paths between adjacent panels. The vertical support extensions have an upper surface for supporting an artificial turf assembly overlying the turf underlayment layer, and the panel edges having one or more complementary indentations corresponding to vertical support extensions of adjacent panels. When the panels move toward each other, thereby closing drainage paths between adjacent panels, the vertical support extensions are received in the corresponding indentations.

1 - 7 . (canceled) 
     
     
         8 . A turf underlayment layer, comprising:
 at least two panels, each panel including:   a top side having a plurality of projections, a bottom side having a plurality of projections, and panel edges,   wherein the plurality of projections on the top side are configured to support an overlying turf and define top drainage channels, and the plurality of projections on the bottom side are configured to rest on a foundation layer;   wherein the panel edges include a vertical extension and a vertical indention, wherein the vertical extension of one panel is configured to be received in the vertical indention of another panel;   wherein the panel edges of the at least two panels are configured to be mated together to define a drainage path, wherein the drainage path has first and second portions that are generally perpendicular to each other; and   wherein the panels further include a plurality of drain holes dispersed over the panel surfaces for fluid communication between the top side and the bottom side of the panel.   
     
     
         9 . The underlayment layer of  claim 8  wherein the vertical support extension defines an angled edge profile between the top side and the bottom side. 
     
     
         10 . The underlayment layer of  claim 9  wherein the angled edge profile defines a 90 degree angle intersecting the one of the panel edges and wherein a thickness dimension of the vertical support extension is less than a thickness dimension of the turf underlayment layer between the top side and the bottom side. 
     
     
         11 . The underlayment layer of  claim 10  wherein the vertical support extension has a surface that is coplanar with the top surface. 
     
     
         12 . The underlayment layer of  claim 9  wherein the indentation defines a complementary profile to the angled edge profile and has a surface that is coplanar with the bottom side. 
     
     
         13 . The underlayment layer of  claim 9  wherein the angled edge profile defines a tapered profile extending from the top side to the bottom side and has a top surface that is coplanar with the top side. 
     
     
         14 . The underlayment layer of  claim 13  wherein the indentation of the second panel defines a complementary profile to the angled edge profile and has a surface that is coplanar with the bottom side. 
     
     
         15 . The underlayment layer of  claim 8  wherein the panels are made from expanded polypropylene.