How I built my Square /diamond shaped Pond.
The Foundations: To cater for the pond weight my foundations were built using square paving slabs layed on top of a layer of sharp sand which itself was layed on top of a layer of hard core. I chose four square concrete slabs layed together to guide me in keeping the pond square and also rotated the slabs 45 degrees to give diamond effect . Aside from using a prefabricated plastic shell and placing it into the ground a good way to make your pond is to use a flexible pond liner placed in a created pond cavity.
The Walls: If you are going to do the project yourself you need to make sure you do a good job creating the boundary walls of the pond cavity. The level of knowledge and skill needed to build a wall is important to build a clean smart looking walls that are going to immediately grab the attention of any viewer looking at the pond. So if you are not confident at building the wall get a builder in to do it for you. My pond walls consisted of 5 course brickwork layed on top of concrete foundation slabs. For the walls I used the same style bricks as my house which made the feature blend in with both the house and the adjoining conservatory. The walls for the pond were kept single rather then double because it would facilitate a bigger pond cavity. The 4 walls of the diamond shape also reinforced each other for strength through interlocking of the brickwork and having the standard 3 holes in the brick for mortar strength. One neat trick I used is to layout the four concrete slabs of the foundation with sufficient separation, and with the shape a perfect square each wall length was an exact multiple of bricks to complete each course- perfect ! This way no one has to cut any bricks to fit the course provided the brick separations and mortar thickness were kept constant throughout the brickwork.