Construction methods for private pools
There are several distinct construction methods for private (home) swimming pools, which are typically called "concrete", "vinyl liner", and "fiberglass". The term "vinyl liner" pool describes the method of lining the interior, not the construction materials, which may be concrete (of various types), pressure-treated wood, galvanized steel wall system, structural foam (polymer) wall system, and recently introduced, fiber reinforced composite wall system.
Concrete pools may be constructed using many differing methods. Concrete pools are not dissimilar to concrete ships: i.e. they are a contiguous shell that will float under certain circumstances. It is therefore essential that an unrestricted hydrostatic valve is incorporated in the pool design. It is not advisable to empty these pools unnecessarily – especially during rainy months – as the operation of the hydro valve is necessary to avoid flotation (and possible destruction) of the swimming pool. The emptying of all pools must be conducted strictly under the supervision of the pool builder or an authorized consultant.
Concrete pools offer greater design flexibility than fiberglass pools and can be constructed in any size, style or shape. This makes them ideal for more challenging sites such as those with limited space, narrow blocks and hillside locations. The ability to individually design a concrete pool means the consumer is not limited to pre-moulded designs. Concrete pools can take on any form, including L-shaped, geometric, free-form, lap pools and out-of-ground pools.
Concrete pools are constructed completely on-site to custom specifications. As such, they take approximately two months to build. The concrete pool construction process includes:
- Set out and pre-start meeting
- Delivery of materials for form work
- Earthworks and hole digging
- Formwork and steel placement
- Concrete shell pour
- Backfill and plumbing
- Waterline tiling
- Step treads
- Bull-nose header on pool edge
- Water features and paving
- Filtration equipment delivery
- Shell clean out and plaster delivery
- Internal finish application
- Fill with water
- Chemical treatment
- Client instruction and handover
In-ground concrete swimming pools mostly consist of a steel-reinforced gunite or a shotcrete shell, capped horizontally with coping. The pool surface is typically marbelite plaster, a cement-based coating sometimes called as a whitecoat or marcite. The waterline is finished with a perimeter band of tiles, normally six inches tall.
The bond beam refers to the top section of the pool wall beneath the coping. This bond beam has an additional steel for the reinforcement bars, often larger in diameter. The bond beam also increases in width (typically 10 to 12 inches) for additional strength and surface area to attach coping. There is a caulked expansion joint between the coping and the pool deck.
One should not attempt draining a concrete swimming pool unless it is absolutely necessary and one is thoroughly familiar with the steps necessary to do this safely. Draining a pool can cause serious damage to its structure.
Re-plastering concrete swimming pools
For re-plastering a concrete swimming pool, a saw cut with a diamond masonry blade is used to cut under the tile line preserving the pool tile, and depending on the contractor, the plaster chipped with electric chisels. Where new tile is being installed, a saw cut is not needed. Workers will simply set the tile out by 0.5 inch, after that, the pool is checked for loose plaster by tapping on various areas of the pool with a tool, which determines where it is needed to remove the delaminated plaster down to the structural shell. Then workers should apply a bond coat to the structural shell. While bond coat is the preferable way to prep the swimming pool for plaster, sometimes the old surface are in poor conditions that all the old plaster has to be chipped off them and this cannot be determined until the pool is empty and inspected. All plaster chips and waste material should be cleaned up and hauled away before any re-plastering operations occur.
After that air is hand driven via hand held chipping tools to remove the existing plaster down in a narrow band or "keyway" under the tile and around all penetrations of the plaster shell. The purpose of this wide groove is to give a nice smooth even transition where the new plaster end at the tile and other in pool fittings. Any other work or improvements to be done on the pool, including transition tile, drains or fitting replacements, should be done prior to the pool being plastered.
Vinyl liner pools
As mentioned above, vinyl liner refers only to the interior surface of the pool, as colorized chlorinated PVC thermoplastic vinyl may be used as the waterproofing membrane in a number of diverse pool construction methods. Vinyl Liner pools are typically more numerous than other in-ground pool types, especially so in European Union countries (including the UK), Canada and New Zealand.
They are very popular in the Eastern and Southern United States, where this pool type is considered to be a less expensive option to gunite concrete and can be quickly installed during a single week. These pools still provide a durable, quality product that can last for several decades. Designed by Cascade Industries engineer Bob West and introduced to the New Jersey public in 1948, the package pools were introduced to the wider American public by Cascade's (c. 1948–1980) VP of sales Ed Gorman by inclusion the 1951 Sears Roebuck catalog as a do-it-yourself project for US$500.00 + delivery and installation.
In the following years many manufacturers worldwide have produced vinyl pool kits of varying styles and quality that can be transported to sites and installed in only a few days. Designs range from simple (and inexpensive) prefabricated wooden, galvanized steel walls, structural foam (polymer) walls, to fiber reinforced composite wall systems. Vinyl liner pools are popular with many pool buyers due to lower initial cost, better insulation, the many liner patterns and colors available, a child friendly embossed non-slip finish, and the fact that the liners are treated to discourage algae growth. Most chlorinated PVC thermoplastic vinyl pool liners are .020" and .030" gauge (0.50 mm & 0.75 mm) and are recyclable when they reach their design life (usually 20 to 25 years in moderate climates). Replacement liners can be installed in one to two days, and providing the basic pool shell is of substantial construction, a pool may have several new liners over its expected life, which could be as much as fifty years in the case of a concrete construction.
Vinyl liners in sunny climates like California, only last about 7–12 years. They then begin to crack and must be patched. This is due to the heat and strong sun.
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