A guide to designing and building an Infinity Pool and how it works

Infinity pools are a design trend in the 21st century for their beauty and pure elegance. The infinity pool however is often confused with the overflow pool or deck level pool so we are here to explain the differences in their design and construction and what makes one infinity pool stand out from the rest.

Natural, outdoor garden pool

How Do Infinity Pools Work?

A true infinity pool design or negative edge pool has to be built on sloped ground, this is because the water level along one or two sides of the pool will flow over these edges into a weir or secondary pool. Most commonly installed overlooking another body of water such as the sea or a lake, making the pool appear to extend to “infinity,” a term described in the Oxford English Dictionary as forever, or the Greek symbol ‘∞’.

An infinity pool edge should not be confused with a deck level pool or overflow pool where the waters edge is the same level as the deck or patio and flows into a grate around the perimeter.

How Does an Infinity Pool Not Overflow

As described above the location of the infinity pool is the first design consideration. Surrounding levels and sight lines have to be carefully considered to achieve the infinity edge look, merging with the secondary body of water. Once the sight lines and position has been determined the materials are the next consideration. A colour closely matching the surrounding body of water has to be chosen or similar in colour to the landscape, where a negative edge pool (infinity pool without the sea or lake to blend) is to be installed.

Infinity Pool Installation Challenges

Infinity pools are technically more complex for 2 reasons:

  1. You are installing a pool on a hillside or slope, this does not only make it logistically more complex but from a engineering aspect this poses different strains and pressures on the pool, which need to be designed into the final output. The overflow edges that would normally have the surrounding ground supporting them need to have a wall structure similar to that of a dam.


  1. The overflow effect of the pool along the 1 or 2 edges needs to be designed to the tolerances involved in a overflow or deck level pool. That is a 1-2mm vertical tolerance along the length of the pool. Otherwise the water will not flow evenly. There also needs to be a complex system of balance tanks and pumps to ensure even with ten or more people in the pool the water, the level will remain constantly overflowing, offsetting the volume of the bathers or ‘displacement’.

How a Compass Pool Is Installed

A compass pool is a unibody lightweight structure made of carbon ceramic and installed in one piece by crane or lifting equipment. Because of this lightweight material it overcomes a lot of the structural issues involved with building a concrete infinity pool. It is also a flexible structure; taking into account any possible ground movement. The close tolerances in the pool level are achieved with an adjustable stainless steel edge making it extremely accurate and quick to install. Water level is maintained using VSD (variable speed pumps) and a computer-controlled water level system, to not only achieve the correct water level but to save on running costs.

How Much Does an Infinity Pool Cost To Run?

Infinity pool designs will naturally cost more to run than a conventional freeboard pool as there is a cooling effect on water flowing over the pool edge, this is greatest when the outside ambient temperature is low, as with the beginning and end of the swimming season in the UK. This can be eliminated using Compass Pools variable water level system (vwls) that is linked to the automatic safety cover so that, when the cover is open and the pool is in use, the water level raises up to overflow the infinity edge into the weir. When the pool is not in use, the water is pulled from a twin safety main drain, as per a conventional pool, giving you the best of both worlds.

Without this system you will be looking at additional running costs in both the heating of the water and the running of the overflow system. The exact number is calculated by a multitude of factors, including, but not limited to: air temperature, wind speed, site exposure, soil type and water content, pool temperature and hours of use; making for a difficult calculation.

picture of infinity pool

How Much Does an Infinity Pool Cost To Install?

Naturally, beautiful things are never cheap and unfortunately the same applies for an infinity pool; for the engineered solutions described above, implemented by a qualified professional installer. An infinity pool is not something that should be attempted by a self builder or first time contractor due to its complexity. In terms of price an infinity pool will typically add a minimum of £30000 over a similar sized conventional free board or skimmer pool. This price is however variable based on the site conditions and access. Compass Pools have been involved worldwide in some of the most technically challenging infinity pool installs from helicopter lifts to pools installed complete suspended in mid air using steel work, with integrated infinity pool covers.

If you are interested in finding out more about the range of pools we offer, why not call us today on 0333 4567 111?

Our team would be delighted to help you with any questions or queries you might have, and we will endeavour to get back to you as soon as we can.

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