Concrete Garden Waterfalls

While their successful construction demands considerable skill, concrete waterfalls make permanent features that have much to commend them. When used in conjunction with rocks and stones, they can be the most effective and natural looking of all moving water features.

Building a Garden Waterfall

When a traditional garden waterfall is constructed from concrete, its excavation must be 10cm (4in) larger all round than the finished feature. If the waterfall will be built on a mound of soil, it is essential that this be allowed to settle or be compacted before work begins. Shrinkage or slippage of the soil beneath the concrete can cause serious fractures. If you have doubts about the soil base, it may be wiser to use a liner or preformed unit instead. Of course, a concrete garden waterfall may be constructed as an integral part of a rock garden which, if soundly built, will provide a suitably solid foundation.

As with concrete pool construction, it is preferable to line the excavation with builders’ polythene, not only to act as a waterproof membrane, but also to prevent rapid dying out of the concrete, which can lead to cracking. If the weather is very warm, protect the surface with damp sacking or a similar material. When the surface has tightened up, sprinkle it regularly using a watering can fitted with a fine rose.

The concrete mixture and construction method are the same as described for a concrete pool, but any rocks or stones must he added while the concrete is still wet so that they become an integral part of the structure. Adding them once the concrete has set will be very difficult, and they will look unconvincing. Therefore, before you begin concreting, you must know exactly what you are going to do and how you are going to place the rocks so that the basins of the waterfall appear like natural stone structures, rather than concrete. Pebbles can be set into each basin, and rocks arranged at the lip to provide suitable water flow.

Concrete waterfalls do not have to take a traditional form, however; the construction method lends itself to a number of variations. One of the most interesting is the grotto, where a pool is constructed with a background that is similar in appearance to a rock garden. At the summit of this, a small cavern is constructed to house a pump outlet set in a sunken container filled with well washed pebbles or stones. The stones extend down a concrete watercourse, into which they are embedded. Water is pumped into the grotto where it emerges from among the stones and wends its way down the pebble-strewn watercourse, which should be planted with ferns and moisture loving plants, to the pool below.

Making a Garden Waterfall from Concrete

1. Excavate the cascade feature,  removing sufficient soil to comfortably accommodate the edging stones. If the excavation is being made on disturbed soil, this should be well compacted.
2. Install the polythene liner, ensuring sufficient overlap along the sides. This will not only act as a waterproof membrane, but will also prevent rapid drying out and cracking of the concrete.
3. Put a layer of concrete down to about two thirds of the required finished depth and place the wire mesh reinforcement over the top. Push this firmly and evenly into the concrete.
4. Add a further layer of concrete over the mesh and tamp down firmly to provide an even finish. Position the edging stones carefully while the concrete is still wet.
5. Dress the floor of the cascade with decorative pebbles set into the final concrete layer. To obtain the best effect, carefully place each one, taking care not to splash them with wet concrete.
6. Cover with damp sacks and keep watered to prevent the concrete drying out too quickly, which often leads to hair cracks appearing, later resulting in larger cracks or flaking of the surface.

Water Staircase

The water staircase makes a complete contrast to the normal waterfall. Widely constructed by the French and Italians throughout the last two centuries, this fascinating water feature can be easily incorporated into the modern suburban garden. As the name implies, the feature comprises a number of steps, which are transformed by sparkling silvery water that tumbles down them. The water staircases of European gardens were very grand affairs, and part of their appeal was their scale. However, an impression of this romantic era can be created in the small garden using concrete drainage pipes. These should be set horizontally, one behind the other, into a bed of concrete laid over a waterproof membrane, each pipe being slightly higher than the one before. This produces a staircase with rounded steps.

The end of each pipe should be filled with concrete or soil, and a suitable arrangement of rocks and planting put into place to disguise the ends. It is advisable to treat the pipes with a sealant to prevent the escape of free-lime into the pool below. The feature will look a little stark to begin with, but once the pipes begin to be tarnished by algae, they will soon look well established. Make sure that the pump is powerful enough to produce a vigorous splashing cover.

Making a Simple Water Staircase

1. Prepare a slope to accommodate the pipes. If it is artificially created permit it to settle. Spread over a layer of builder’s polythene to act as a waterproof membrane before laying concrete.
2. A stiff mix of concrete should be made and placed over the polythene. Starting from the bottom, set each pipe firmly in the concrete, placing the next evenly behind it.
3. When all the pipes are in position, the ends can be disguised with concrete, soil or stones. A slight upstand of stones at the cemented in edges will ensure that water does not seep from the edges.