There are a number of ways in which a swimming pool may be constructed and here we describe the methods we use when constructing a new liner pool.
1.0 Liner pool construction
1.1 Solid block pool wall construction
After the hole is excavated, a concrete foundation beam is formed around the perimeter to provide support for the pool wall, which is constructed at a constant height. The concrete blocks may be solid dense concrete blocks each measuring 215mm x 440mm x 100mm and will have a minimum crush strength of 7 Newtons / per square metre. The blocks are laid face down for additional strength.
1.2 Hollow block pool wall construction
In certain situations hollow blocks of the same strength will be used. The swimming pool wall is further strengthened by reinforcement using high tensile steel both horizontally and vertically and then filling the hollow concrete blocks with concrete.
This method is usually employed where one part of the surrounding ground is lower than the pool wall or the soil conditions are unstable and a strong self - supporting wall is required.
1.3 Panel pool wall construction
If the pool walls are entirely below ground then a manufactured pool wall panel can be used, the concrete ring beam is used as in the other methods described above to support the panels.
The polymer panels are manufactured in factory conditions and are delivered to site and tied into the concrete foundation beam with 6mm reinforcing bars.
The modular panels which are in set lengths of 2’, 4’ and 6’ are then held together by means of prefabricated wall braces which are also manufactured from polymer material.
The wall braces not only splice the wall panels together but prevent deflection of the wall. The corner panels are produced with a preformed radius.
The apertures for the pool fittings are already cut in the panels and are easily installed by fitting them with self - tapping screws into the pre-drilled holes in the panels
This method of pool wall construction is faster than using conventional blocks and in most cases the pool wall can be erected by 2 people in 1 day.
Because the interior face is smooth it does not require a render to the pool wall panels, thereby saving more time.
1.4 Entry steps
If internal entry steps are required then these are built after the pool perimeter wall is completed and these are constructed form solid concrete blocks
If external steps are to be fitted then a preformed GRP step is fitted in the required position in the pool and tied into the block wall construction
If the steps are to be fitted into a panel pool then the preformed step unit is bolted onto the specially formed polymer panel and these can be internal or external steps.
1.5 Pool fittings
The pool fittings such as skimmers, inlets, vacuum point and underwater lights for the pool are generally installed as the walls are erected. These are manufactured items usually made form Cycolac or other pre formed plastic material.
1.6 Pool pipework
The pool pipe work which connects the pool fittings to the filtration plant is usually made up from 2” and 1.5 “ Class C ABS pipe and solvent welded to ABS fittings. In some cases PVC pipework and fittings are used.
1.7 Internal render and screed to the pool
A sand cement render nominally 20 - 25 mm thick is applied to the block walls and a proprietary waterproofing agent is added to the mix before application.
A screed is then applied to the pool floor and the thickness (between 60 – 70 mm) will depend upon the prevailing soil conditions. If the soil conditions are very poor and unstable then a lean mix of concrete will be applied to the soil before receiving the screed.
After the pool shell is rendered an underlay is laid on the floor and walls to minimize abrasion between the render and the underside of the liner.
In addition to prolonging the life of the liner it also makes the pool floor more comfortable to walk on.
This is especially important in pools of a constant depth where pool users spend an amount of time standing on the floor when playing games.