Garden Ponds – Pool Edgings

The edges of a pool are among the most difficult aspects of the construction to finish off effectively. The treatment applied can either make or mar the whole feature aesthetically, and the manner in which it is achieved can have a considerable effect on the longevity of the pool structure. An ill-conceived edge, especially around a lined pool, can create all manner of problems.

There are almost as many forms of edging as there are types of water garden. A variety of traditional edgings is available, but there are other innovative kinds, too, which provide further opportunities for developing interesting waterside features.

COMPATIBLE EDGING

Visually, the edging must fit in with the overall style of the feature. A formal pool is normally easier to cope with, as it can be surrounded by paving or coping stones.

Provided that the edge of the pool is level, there should be no serious impediment to achieving a neat formal finish.

However, paving stones often look out of place if used around an informal pool. You may be able get away with this if they are used at the front of the pool, while the remainder is surrounded by vegetation. Indeed, there is a practical purpose in using paving, provided that it is tastefully laid, as it will reduce wear on the lawn at the most natural point for anyone to stand and observe the pool or feed any fish. A couple of well placed paving slabs will be much more satisfactory than soggy worn turf.

Wildlife pools look ill at ease when any hard landscape materials are used around them. Instead, a planted or grassed edge should be employed, although this will be very difficult to make convincing and, in the ease of grass, the most difficult to maintain.

PAVING

Irrespective of the pool construction method used, paving can be successfully installed as an edging. It is essential that the pool is level from side to side and end to end, and that sufficient surrounding ground has also been levelled to accommodate the paving.

The slabs should be laid on a mortar bed, about 2.5cm (1in) thick, using a mixture comprising five parts by volume of builders’ sand and one part of cement. Combine these thoroughly in their dry state, then gradually mix in water until you achieve a stiff, but wet, consistency. Spread enough mortar along the edge of the pool to bed two or three slabs at a time, taking it out to the width of the slabs. Trowel it off roughly level. Do not lay all the mortar in one go, as it is likely to dry out before you finish bedding the slabs.

Each paving slab should be firmly bedded on the mortar and overhang the pool edge by about 5cm (2in). This will help disguise the construction material and, in the case of a pool liner, provide some protection from the possibility of bleaching by the sun.

Make sure that each slab is level in both plains with a spirit level. Once all the slabs have been laid, the gaps between them can be pointed with mortar, but take care not to let any fall into the water and seal them to prevent lime from leaching into the pool.

A GRASS EDGE

Some pool designs only work well where there is a natural turf edge. For the most part, these are constructed for the beauty that still water can offer, rather than for myriad colourful aquatic plants. They act as focal points in a landscape and are natural forms of art. In practical terms, however, a pool with turf running right to the water’s edge can produce maintenance difficulties. Not only is there the constant problem of grass mowings falling into the water, but also the possibility that applications of lawn feed and weed-killing preparations will seep into the pool.

The important consideration with a turf edge is the depth of soil required over the edge of the pool construction. To ensure that this does not dry out, a minimum depth of 5cm (2in) is required, although 10cm (4in) would be much better. There is nothing worse than a verdant summer lawn spreading towards a pool surrounded by a yellowish border, indicating a lack of moisture.

Of course, if the edge is carefully contrived and the grass laid as turf, which is in contact with the water, provided the pool is kept topped up, water will seep up through the turf by capillary action and the grass will remain healthy. It will soak up quite a lot of water during hot summer weather, and as the pool will also lose some of its contents through evaporation at this time of year, diligence will be required to ensure a consistent water level.

A PLANTED EDGE

A planted edge is by far the best solution for an informal pool. This can be achieved with the aid of strategically placed rocks and soil pockets, but great care must be taken. Use the rocks to form a barrier around the edge of the pool and, where a liner has been used, to secure this, too. Placing the rocks so that they overhang the water will also help to conceal the pool construction.

Unless the edging is to be a link between a rock garden and the pool, use rocks of modest size. Narrow flat rocks are ideal. These will form a retaining edge for the soil and should be largely disguised by the tumbling foliage of the plants established behind them.

Good soil preparation is vital to the success of such a venture, while sufficient depth must be available to establish the plants successfully. Often the depth of soil will be limited, and although the plants will be in close proximity to the water, they are unlikely to be aquatics, for in the summer the soil conditions could be quite dry. Consequently, some of the more boisterous rock garden plants would be appropriate.

Place the rocks in position and fill behind them with a good soil mixture incorporating a generous quantity of organic matter to help retain moisture. Plant behind the rocks and, where appropriate, add a second layer, either immediately behind or above. If you feel that rocks would be too large or intrusive, a similar edging can be contrived by laying paving slabs with pockets of soil between them. Once the plants are established, they will tumble over the slabs, softening their harsh angular lines. If the slabs are likely to be walked upon, they will need bedding on pads of mortar to ensure that they are stable and will not tilt.

USING TIMBER

Although not as permanent as traditional rock or paved edges, timber can prove extremely useful and versatile. If the pond is being constructed in conjunction with wooden decking or a causeway, timber edging will be a natural extension of this garden feature. There are several ways of fixing it, depending upon the effect you want to achieve. If the surface of the water in the pond is to be level with the surrounding ground, a fairly elaborate system must be employed. This involves constructing a concrete surround, into which a solid timber edge is bolted and which lies flush with the surrounding soil. The liner is trapped between this section of timber and the wooden edging that will sit in the water. Timber plating joints are used to hold the two wooden sections tightly together. Their screws do not penetrate the liner and, therefore, permit the water level to come right to the top without any fear of seepage.

If most of the timber edging is to be exposed, a similar system can be used, but instead of plating joints, screws are driven through the face of one section into the other. Since these will be above the final water level, it does not matter if they pass through the liner. Indeed, with this arrangement, the water should barely reach the bottom of the timber.

BRICKS

While paving slabs are the traditional edging for a formal pool, a properly executed brick edging can look superb. It is vital to use only engineering bricks or decorative bricks that are intended for outdoor use. These will not flake or shatter if exposed to frost when soaked with water.

The decision to employ a brick edging must be made early in the planning stage so that a rim to accommodate them can be formed when the pool is excavated. They should be bedded on mortar in the same manner as paving slabs, the face of each brick being ‘buttered’ with more mortar before placing it alongside its neighbour. Keep the joints between the bricks uniform, about 1cm (3/8in) wide, and carefully remove any mortar that squeezes from between them. Make sure none falls into the water. When all the bricks are in place, point the joints with more mortar.

THE BEACH

Beaches have become very fashionable features, especially for water gardens where wildlife is the major interest. Attractive, as well as simple to make, a beach will provide birds with an opportunity to bathe and give errant hedgehogs an escape route from the pool if they tumble in.

The simplest method of making a beach is to trap the edge of the liner between two rows of bricks or stones. This arrangement will allow it to he pulled tight and kept at a consistent level. The area in front, behind and over the bricks should be covered with cobbles and pebbles. This type of edging is very economical to install and looks good, but it will not produce a beach that will withstand constant wear.

If you intend regularly walking or standing on the beach, a more robust foundation will be necessary. Lay a shallow concrete footing on top of the liner, having allowed in the excavation for the depth of two bricks before reaching the surface of the beach. Lay the bricks as a low wall, pull the liner up behind them, then bank concrete up against it. Finally, add the cobbles or pebbles, covering the entire area.

Pebble Beaches

For a simple pebble beach in an inexposed area, the edge of the linger can be trapped beneath and between two rows of bricks or stones. These are then covered with cobbles or pebbles. This is an economical and simple edging for an informal pool, but it will not withstand constant wear. When heavy foot traffic is likely to be experienced a the pool side, a more substantial foundation will be necessary. Lay a shallow concrete footing on top of the liner and build a small wall, trapping the liner in place behind it. Bank concrete up against this, then cover the whole area with cobbles or pebbles.