EDGE SYSTEM DESIGNS
When designing your swimming pool, one important aesthetic and practical decision that needs to be made is what edge design do you want. There are two standard systems, freeboard and deck level. Freeboard is fairly straightforward, however deck level has a number of different designs within the overall system description. Here we’ll look into several of the systems, which may give you some ideas when thinking of your swimming pool finishes.
Freeboard (Skimmer Pools)
The freeboard design is fairly straightforward. It generally consists of skimmer units distributed around the perimeter of the pool to allow for the suction of surface water, keeping it clear of debris. The number of units is dependant on the surface area of the water body (and the size of the skimmer units utilised).
Generally, the ‘freeboard’ or distance between the water level and the perimeter surround level is approximately 150mm, with the centre of the skimmer mouth being positioned at the finished water level. There are some alternatives available both commercially (or bespoke) that allow for a reduced freeboard, however care should be taken when considering a reduced freeboard distance with the structure termination to minimise potential leakage between the perimeter edge finishes and the water body structure.
Please see below some examples of freeboard pools where you can see clearly the distance between the water level and the perimeter surround.
Deck Level (Overflow Pools)
The deck level design provides a complete surface skimming of water via the overflow channel(s) and balance tank to the filtration system. The balance tank volume is calculated and designed based on the surface area of the swimming pool in order to allow any displacement of water by the bathers to be contained within the balance tank, and returned to the swimming pool after the bathers have exited.
Within the ‘deck level’ group there are a number of different design options including:
Overflow Channel Grating Systems
This is probably the deck level system you are most used to seeing on swimming pools. The channel grating can be manufactured from a number of different materials including ABS/PVC, stainless steel and cut stone, with various colours and designs available to suit your aesthetic or practical requirements.
Slot Drain Systems
An adaptation of the grating system, where the channel is finished by using stones installed in a manner that allows the surface water to pass through a narrow slot into the channel. Careful consideration should be taken in the slot design to ensure that the width of the slot doesn’t pose a health and safety concern, and that surge water splashing over the slot is kept to a minimum. In many cases we design the dry side stone very slightly higher that the wet side stone to minimise this issue.
The hydraulic design procedure for infinity edges is very similar to that of any standard overflow pool, in that the surface water will pass over the infinity edge, into a channel and to the circulation equipment via a balancing tank. The key difference is that in order to achieve an infinity effect, the level of the channel is installed lower. The original infinity effect was to give the appearance that the water is disappearing into the horizon, especially in swimming pool installed adjacent to the ocean. This design however has also been incorporated on projects whereby the client may wish to have varying levels for their pool surrounds, providing an additional feature or effect.
As you can see from this sketch, when designing a true infinity effect, careful consideration should be taken to ensure the levels of the external channel do not obstruct the line of sight.
Whilst we have touched upon a few different examples above, there is no limit to the variation and options available. If you have any ideas that you wish to discuss, or would like to find out what design best suits your project then please don’t hesitate to get in touch.