Specifically designed to help quickly and easily build beautiful water features, this polyurethane foam expands to fill gaps and cracks to help direct water to flow over the rocks in a waterfall, rather than under and in between.
 
HERE'S WHAT MAKES GREAT STUFF™ POND & STONE GREAT:
Is black in color to blend in with stones and shadows
Bonds without mortar
Helps direct water over, not under, rocks
Creates a water-shedding bond for stone, rock, masonry, concrete and other building materials
Safe for ornamental fish and plants
Lasts for years in wet conditions
 
It's easy to work with because it:
All-direction dispensing
Can be applied to damp and dry surfaces
Cures in 8 hours1
Is UL Classified