If you are building a deep pond, it is assumed that there will be reinforcing rods in the foundation to prevent the base of the wall from “kicking” out from the water pressure.
You will notice that the double wall and reinforcing is supplemented by a third row of bricks that serves a double purpose. The first is to strengthen the bond between the foundation and the wall. The second reason for the third row of bricks is to eliminate sharp corners and to ensure a rounded smooth finish during the benching process.
The walls can be build with bricks, concrete bricks or concrete blocks. All of them are effective but one must consider the various options carefully.
Clay bricks have been designed with either holes in them or they are concave shaped to provide excellent adhesion to the mortar. Clay bricks are easy to handle because of the relative small size and weight. It also accommodates sharp turns in the shape of the pond more readily. Normally, when constructing large ponds, the walls are build with a double row of bricks and then the cavity between the bricks are filled with concrete. In smaller shallow ponds, this precaution will not be necessary. A disadvantage of clay bricks are the tendency of some individual bricks in a batch to erode under wet conditions.
Concrete bricks are solid and strong with the same dimensions without the potential weakness that they will erode over time. One can also build two or three rows of bricks, depending on the desired thickness of the wall. Concrete bricks offer the same advantage as clay bricks, but there is no danger of eroding/crumbling over time.
Concrete blocks can also be used successfully and they form a very solid wall. Unfortunately they are extremely heavy and difficult to lay as they are not easy to put into place when laid on the mortar. Insert vertical bars into the hollow areas. These areas are then filled with concrete so that the blocks are bonded together. Sometimes these blocks are laid on their side to give a wider, stronger wall.
When the walls are complete, the space behind the walls should be back-filled. Ordinary soil, especially if it is heavy clay should not be used. The best material for back-filling is chippings, stone dust or concrete.
Updated 12 April 2009
Last Updated on Sunday, 12 April 2009 18:54