The majority of formal ‘in-ground’ swimming pools in the UK have areas of hard standing surrounding them for reasons of safety and cleanliness/ease of maintenance. These are mainly comprised of timber decking or paving of one type or another.
There are several different types of pool construction, including pre-formed liners, bespoke designs with curved edges in free-formed concrete, poured under pressure on to steel fabrications in situ depicting shapes from guitars to galleons, affording many possibilities for a keen garden design and build company to create something imaginative in paving (or timber).
In practical terms, the surround is there for reasons of personal comfort, allowing loungers and deck chairs facilities, with space to move around without impeding pool users, who are likely to have wet feet and dripping swimwear, requiring a non-slip surface as far as possible.
Having full knowledge of the method of construction of the in-ground pool is essential. Establishing the type of soil the pool in which the pool has been installed is also important, as is the likely ground water table. Heavy clay ground will require some external dewatering pumping system installed to prevent ground water from potentially lifting/raising the pool shell when empty or semi-drained during winter months. If fitted, check that this feature is operating correctly before starting any planning works.
Some pools are built using a semi-rigid liner, then clad internally with mosaic style tesserae or small element ceramic tiles. Others are constructed using concrete blocks filled with concrete to create formal rectangular or square pools. Knowing the style and type of construction is the most immediate criterion for deciding or nominating a paving solution to provide a pool surround proposal.
Whilst the majority of existing pools will have been fitted with coping stone edgings, others may require the proposed paving project to extend to include the edges. Most types of paving slab will have an edge of 20mm, which may be considered too thin for comfort, even when bull-nosed, to prevent sharp or uncomfortable units.
We see too many complaints regarding swimming pool paving surrounds, where the contractor has not taken into a number of factors into consideration. These include;
- Coping stones too thin/sharp/uncomfortable when climbing out of the water.
- Paving laid over a permeable bed of MOT Type 1 and sharp sand/cement laying bed, with permeable grout, allowing water to percolate through the layers then retained by the concrete areas of the pool construction causing frost damage during the winter.
- Permeable grout and laying bed allowing water to enter behind the pool liner and pushing the tiles/tesserae from the walls, especially at or near the top of the pool, just under the edge coping stones.
- Laying unsealed sandstone paving with insufficient falls, whereby moisture is absorbed into the paving, creating problems with algae and discoloration, requiring regular cleaning and washing with chlorine to maintain a clean appearance and safe walking areas.
- Porcelain paving slabs when laid with 10mm joints in a chequer-board design, where four corners meet. Unless the slabs are fully slurried underneath, and a full grout is maintained, these relatively wide joints can allow the grout to ‘slump’ within the corners, creating sharp gaps likely to cut small toes when walked on with wet, bare feet.
Essentially, all paving projects surrounding a swimming pool involve a wider range of possible problems that go beyond simply specifying a paving job.
If the pool has been constructed with a solid concrete foundation surrounding the in-ground feature, any paving scheme must also be impermeable, including laying bed, product and grout.
This may be sealed sawn natural stone – sealed all six sides – or porcelain, to ensure no moisture can penetrate the sub-base, or importantly – between the liner and the ground which may cause issues with hydrostatic pressure pushing the internal tiles away from the liner.
Salt Water Swimming Pools
There is currently an increase in popularity in salt water pools, where the standard chlorinated cleaning system is replaced with a different type of filtration plant that uses salt to both soften and clean the water. Within the pool pumping system, the use of chlorine is removed from internal workings, although it may still be used around the pool surround for cleaning purposes.
The use of salt may corrode natural stone paving, and cause rust problems with ferrous metal fittings including steps, chutes and other metallic items in use around the pool area.
Always ask for construction details from the installer or owner before making and decisions or estimating the likely costs involved in the works required for the project.