Waterproofing a Concrete Block Pond for a Bronze Fountain

A 6-inch concrete foundation with block walls needs interior sealing to hold water. Concrete is porous; blocks have mortar joints that wick.

Sealing Steps

1. Clean walls and floor thoroughly; remove efflorescence.
2. Apply a cementitious waterproof coating (e.g., Thoroseal, Drylok) in 2–3 coats.
3. Or use a pond-grade epoxy or rubberized membrane (e.g., Pond Armor, Liquid Rubber).
4. Seal all joints, corners, and penetrations with hydraulic cement first.
5. Test fill for 48 hours before adding fountain.

Pro Tip

Visit a pool supply store—they carry professional-grade sealers for concrete pools that work perfectly for ponds.