A concrete pool shell is cast to your site rather than delivered to it. That one fact explains most of its benefits. You choose the shape, the reinforcement sits where the structure needs it, and you can renew the finish later without touching the structure beneath.
Every pool Trademen Pools builds starts as a concrete swimming pool. Marbelite and fibreglass are both finishes applied over that shell, so the shell is the part of the job you only get once. This article covers what goes into it, what it gives you and where it asks more of you.
What goes into pool shell construction
The shell is a reinforced concrete bowl, and every stage has a job. The crew marks out the site and squares it first, because a pool that starts out of square never finishes square. Excavation follows, by hand and/or TLB depending on access and space.
Reinforcement goes in next: Y8 steel bars, 100mm mesh wire and a ring beam. The ring beam ties the top edge together so the walls work as one concrete structure. The concrete itself is 30 MPa ready-mix from a reputable supplier, poured to a thickness of 150mm. Ready-mix arrives at a specified strength, so the shell does not depend on a batch mixed by hand on site.
Why a concrete pool shell suits South African gardens
Stands in South Africa vary enormously. One property has a wide side gate and a flat lawn. The next has a narrow passage, a retaining wall and a slope. A shell poured on site adapts to both. The crew digs to your levels, forms to your outline and reinforces to your depth. Your garden does not have to fit around a fixed mould.
Shape is where this matters most. A poured concrete pool can follow a garden boundary, wrap around an existing tree line or sit square to the architecture of the house. If you want a free-form outline, a deep end in an unusual position or a long, narrow lap pool, concrete lets you draw it and build it.
The shell outlasts the finish
A pool has two layers with different lifespans. The shell is structural and sits behind the water. The finish is the surface the water touches, and it takes the chemicals, the sun and the wear. Trademen Pools guarantees the shell for 10 years and the marbelite or fibreglass finish for 5, and that split reflects the difference.
The practical benefit is simple. When a finish tires, you renovate the surface and keep the structure. A concrete shell pool takes 2 to 3 weeks to build new. Remarbelite and refibreglass jobs each take 3 to 5 days. You do not dig the pool up and start again.
The cost gap is just as clear. On a 6×4 pool, remarbelite runs about R18,000 and refibreglass about R25,000. Each is quoted as one overall price, and minor changes such as a light or sand change sit inside it.
What the shell decides and what the finish decides
Buyers often mix up the two layers when they compare quotes. This table separates them.
| Decided by the shell | Decided by the finish |
|---|---|
| Shape, length, width and depth profile | Colour and surface texture |
| Wall thickness and reinforcement | How the pool feels underfoot |
| Where the weir, aim-flow and LED light sit | Matte marbelite or smooth, slightly sheened fibreglass |
| Where the suction and return pipework runs | Ceramic mosaic tile detail on marbelite pools |
| 10-year guarantee on the concrete shell | 5-year guarantee on the finish |
Read it as a decision order. Settle the shell first, because it is permanent. Choose the finish second, because you can change it later.
Marbelite or fibreglass over the same shell
The shell does not force your hand on finish, and each option has a real case. Marbelite gives you a classic, matte plaster look that suits natural stone and warmer, more traditional exteriors. It also takes ceramic mosaic tiles, which lets you add a tiled band or feature.
Fibreglass gives you a smoother, more consistent surface with a slight sheen. It suits cleaner, contemporary lines, such as those in newer apartment developments. Neither finish is the wrong answer. The right one depends on the house, the garden and how you want the water to look and feel. For a second view, Pool Guru’s comparison of fibreglass and marbelite finishes sets out the differences from a supplier’s side.
How concrete shell construction runs, step by step
- Mark out and square the site.
- Excavate by hand and/or TLB.
- Fix the Y8 bars, 100mm mesh wire and ring beam.
- Pour the 30 MPa shell at 150mm.
- Position the weir, aim-flow and LED light while the concrete sets.
- Cure the shell for three to five days.
- Apply the finish, then fit the copings and paving.
- Install the “Box”, connect the fittings, then fill and commission the pool.
The order matters more than it looks. The weir, aim-flow and light go in while the concrete is still setting, so they bed into the shell instead of being forced into it later. Curing then comes before any finish, and the shell needs those three to five days to settle.
The finish stage splits by material. A marbelite job gets ceramic mosaic tiles and 50mm PVC suction and return piping first. The crew then applies the marbelite and leaves it to cure overnight. A fibreglass job is plastered and left to dry completely before resin and gelcoat go on. That drying time is not negotiable, and the crew does not hurry it.
Copings and paving follow the finish. Bull-nose copings are normally 450x450mm flagstone, and paving at the same size creates a 900mm apron around the pool. The “Box” then goes in as one unit. It holds the pump, sand filter, electrical distribution board with a battery-backed timer, and the pump house. The crew wires the weir, aim-flow and light back to the board, then fills and commissions the pool.
Where a concrete pool shell asks more of you
Concrete is not the quick option, and it helps to know why. It involves more hand labour and more stages than a factory shell. A 6×4 marbelite pool costs about R78,000 and a fibreglass pool about R85,000, with 2 to 3 weeks on site. That cost and time buy you shape freedom and a structure built to your ground.
Access is the main variable. On a tight stand, a TLB may not reach the dig, so more of the excavation falls to hand labour. The crew then needs a plan for staging materials and removing spoil. Tell your builder early about narrow gates, shared driveways and retaining walls. A surprise on day two costs more than a plan on day zero.
Council paperwork also comes with any new pool. Council typically requires approved drawings and a signed indemnity form before work starts. Trademen Pools handles that as part of the build, so you do not chase it yourself.
Common questions about concrete pool construction
How thick is the concrete in a pool shell?
The shell is poured to 150mm. It uses 30 MPa ready-mix with Y8 steel bars, 100mm mesh wire and a ring beam.
Can I still choose fibreglass if the shell is concrete?
Yes. The crew plasters the shell, lets it dry completely, then applies resin and gelcoat. The concrete is the structure and the fibreglass is the surface.
How long does the shell take to cure?
Curing takes three to five days. A new pool then takes 2 to 3 weeks in total, depending on access and finish.
What happens when the finish wears out?
You renovate the surface and keep the shell. Remarbelite and refibreglass jobs each take 3 to 5 days.
If your site has a tight gate or an awkward slope, raise it while you are still deciding on the shape. A concrete pool shell can be designed around those limits, and the Trademen Pools team will plan access, staging and spoil removal with you before the first spade goes in.
Get your concrete pool shell priced
The shell is the part of the pool you only build once, so its shape, depth and reinforcement are worth settling before digging starts. Request a quote for your site, or email Trademen Pools for a non-binding quotation.