Walls can be constructed as purely functional structures, perhaps to retain an earth bank or to act as a boundary between two properties, or they can be constructed as a feature in their own right, perhaps to add height to a flat garden or to aid in the construction of another feature.

As can be seen in the picture of the water flowing from the dry stone wall, here Gardencraft constructed a stream within a garden and needed to create a suitable source for the water, thus a wall was built with a clay pipe set within, through which water could be pumped to give the illusion of an overflowing land drain.