9 things to consider before building a swimming pool

Is a swimming pool on the top of your wish list? Here are 9 things to consider before taking the plunge and building your own


9 things to consider before building a swimming pool

If you have a swimming pool in the backyard, chances are your kids (and the neighbours’) will be spending hours in and around it this summer. Maybe installing a pool is still on your wishlist, like many other Kiwi homeowners.

Whatever stage you are at, there’s no doubt a swimming pool is a major investment and the range of options – in-ground or above, concrete or fibreglass composite, painted or tiled, infinity edge or lap pool – is increasing all the time. As we know, the key to making good investment decisions is doing your homework, so if you’re keen to have a pool in your garden, here are some questions you need to answer.

1 Why have a pool?

Start as you would with any big project by establishing your reasons for wanting a pool. These will have a big influence on its shape, depth, size and possibly even the type of construction. Will you use it for laps, recreation or relaxing? Is it for your children and their friends, to enhance a view, or to act as a focal point for the garden?

If you have a clear idea of its purpose, the rest of the decisions (and there will be many) won’t be so hard to sort out. But before you progress your pool any further, make sure you ask the hardest question – will you use it enough to justify the expense?


2 Is my site up to it?

Swimming pools are easier to build on a level site so if your section slopes steeply, construction costs will be higher. Ground conditions such as a high water table or very sandy, rocky or unstable soil will also make building trickier. Do you live in an area prone to earthquakes, slips, stormwater run-off or flooding? You may need to commission a geo-technical engineering report or, at the very least, have soil tests done to assess the site’s suitability.

The size and location of your property will naturally determine the size and shape of your pool. Tiny urban sites have strict requirements regarding any type of construction close to boundaries, for instance, and shading from other buildings or neighbouring trees will also limit where you can position a pool. However, a clever designer can often help find solutions to such issues.


3 Where do I put it?

Once you’ve decided on the type of pool, it’s time to work out where to position it. First, check council and building regulations regarding site coverage allowance, pool fencing requirements, proximity to wastewater fields and so forth, as well as the location of utilities such as gas, electrical, telephone, cable and water lines. Other factors to consider include:

  • View of the pool from inside the house and the rest of garden. Adding lighting or water features will make it more attractive when not in use. Being able to see the pool from the house is essential if you have children.
  • Does the location maximise sun exposure to help keep the water temperature warm? Large trees around the pool will block sun and their leaves will drop into the water.
  • Wind exposure will cool the water and also increase evaporation. Plant or build screens to shelter the pool.
  • Circulation routes. How will people enter and exit the pool?
  • Poolside relaxing and entertaining. Where will you and your guests hang out around the pool?
  • Where will you keep the filtration equipment, pool cleaner, toys and sun umbrellas? Is there room for seating, a shade structure, or even a changing area?


4 Alternatives to chemical cleaning

The natural pool is a new trend finding favour with those who dislike pool chemicals and prefer a more naturalistic look in their gardens. These in-ground pools are lined but rely on natural processes and filtering, including plants, to keep the pool clean.

5 What will it cost?

The cost of a basic concrete pool is similar to one made of fibreglass composite (from around $35,000), but as many concrete pools have a customised shape and size, their price is often higher.

You will have to spend closer to $55,000 for a concrete pool, and many additional costs need to be factored in, including heating, covers, decking and landscaping. Then there are the ongoing costs of filtration (running and servicing pumps and filters) and keeping the water clean (chemicals, saltwater chlorinators, self-cleaning units and suction cleaners).


The largest maintenance cost for swimming pools is the lining. Some concrete pools may need to be acid-washed every three to five years and re-plastered or re-surfaced every 10-15 years. Vinyl-lined pools can puncture so you should allow for repairs every five to 10 years. Fibreglass composite pools are low maintenance and often come with a lifetime warranty.

Swimming pools and spa pools are required by law to be fenced, except where an exemption applies. A building consent is required to build or install a pool. Local council by-laws may also apply.

6 Build it above or below the ground?

The first question to consider when determining your pool’s construction is whether the pool should be in the ground or above it. Soil excavation and removal is costly but in-ground pools generally have a more permanent feel than most above-ground types.

However, if you have a steep site it may be cheaper, faster and easier to install an above-ground fibreglass pool with a surrounding deck, especially if access is tricky. If you’re not sure which type of pool is best for you, talk to local pool contractors, ideally those recommended by people you trust.


The cheapest swimming pool option is a prefabricated, above-ground type, usually made from fibreglass or steel with a vinyl liner. DIY models that can easily be disassembled are great if you are renting and want to take the pool with you when you move.

Options range from basic models with no filtration to larger types suitable for swimming laps that include extras such as decking, steps and filtration equipment. Most have a limited lifespan.

7 What materials should I use?

The two most popular materials used for pool construction in New Zealand are concrete and fibreglass composite. Vinyl pools, used more overseas than here, are another option. They have a pre-formed flexible liner, which fits into the hole and is attached to a reinforced wall frame made of steel, aluminium or a non-corrosive polymer.

A steel-reinforced in-ground concrete pool has traditionally been viewed as the strongest and most durable pool option but advances in fibreglass composite technology have increased this material’s longevity and strength vastly.

Although the use of sprayed concrete techniques (rather than boxed poured concrete) has speeded up the process, the installation of a concrete pool is still lengthier than if you are using fibreglass because the pool is built entirely on site. Concrete construction is also very weather dependent and the porous nature of concrete can lead to algae and mould issues if the interior surface is not properly finished.


Concrete still offers the best flexibility in terms of shape, size and depth if you want a customised design. You can also personalise other features, such as an infinity edge or a ‘beach’ (gently shelving) entry to the pool. There are lots of options for finishing a concrete pool’s interior, too, including marble plaster, tiles, pebbles, coloured quartz, swimming pool paint or vinyl. You can also re-plaster or repaint existing concrete pools more easily than most other in-ground types.

Fibreglass composite pools are pre-moulded into various shapes and either positioned into an excavated hole or set above ground (built with extra-strength stiffening supports). Although you generally can’t personalise fibreglass pools as they’re pre-made, the range of styles, shapes, sizes, colours and finishes keeps increasing.

One of their biggest attractions is the ease and speed of installation. They are also finished with a smooth gel coat that is very durable and resistant to stains and mould (meaning fewer chemicals to treat the water). Fibreglass composite pools are more flexible than concrete, making them a good option for earthquake-prone areas.


8 Who will build it?

Ask for referrals from friends and colleagues who own pools you like or go for a certificated member of the Master Pool Builders industry group (NZMPB), which offers a disputes process.

9 Mistakes to avoid

  • Choosing the wrong location for the pool so you can’t move around it easily, it’s too shaded or there’s no space for sunbathing and relaxing.
  • Getting a diving board that you hardly ever use. You need a deep end for diving boards, which adds to the cost of your pool and young kids need to be closely supervised when using it.
  • Skimping on decking or paved areas around the pool to save money. Remember that people spend more time beside the water than in it and trying to add more space after the construction process is finished can be expensive.
  • Buying on price alone. Cutting corners is not worth it with swimming pools.
  • Underestimating the size of the project and the resultant upheaval. Expect dirt and chaos and you’ll handle them better when they happen.

Words by: Carol Bucknell. Photography by: Tony Scott, Angelita Bonetti, Armelle Habib/

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