In this article
A concrete pool is strong and built to carry the weight and pressure of water for many years. That strength depends on its protective layers staying intact, namely waterproofing, grout and tiles, and on the soil beneath staying stable and dry. Neglect does not break a pool directly. It starts a chain of small failures, each leading to the next, until cracks appear in the floor and walls.
This article follows that chain step by step, from a small leak or unbalanced water to soil, concrete and steel damage, then explains severity levels and the right repair for each. The aim is to show where you can stop the chain before it becomes a structural repair.
The damage chain from neglect to cracks
- Long periods of unbalanced water: low pH dissolves grout, high hardness leaves deposits that stress surfaces.
- Open grout joints: water gets behind tiles and sits against the membrane.
- Weakened waterproofing and a first leak: small enough to go unnoticed while the pool is topped up.
- Soil affected: leaking water wets dry soil, which swells, washes out or settles.
- Concrete stressed: the shell now rests on changing ground and cracks.
- Water reaches the steel: cracks let water reach the rebar and rust begins.
- Cracks widen: rusting steel expands, pushing the concrete apart from inside.
Every stage can be stopped if caught in time, and every stage passed increases the repair needed.
How leaking water affects surrounding soil
- Sandy soil can wash away, leaving voids under the floor.
- Clay swells when wet and shrinks when dry, repeatedly pressing on the concrete.
- Poorly compacted fill settles faster once wet.
External signs include sinking paving around the pool, a gap opening between coping and deck, cracks in nearby floors or walls, and persistent damp on one side.
Cracks from thermal movement
Pools in Riyadh and many Saudi cities face long periods of intense heat. A full, maintained pool handles this better because the water shields floor and walls from sharp changes. A neglected pool is often left empty or with a low level, so large areas bake in direct sun and then cool at night. These daily cycles stress tiles, grout and render and open surface cracks that later let water in. Worse still is draining a neglected pool and suddenly refilling it with cool water on a hot day, which can cause new cracks quickly.
Rebar corrosion beneath the surface
Steel inside concrete is protected by concrete cover and an alkaline environment. When water, especially chlorinated and salty water, reaches it through cracks, that protection breaks down. Rusting steel grows in volume and pushes on the surrounding concrete, widening cracks and sometimes spalling pieces off. Signs include:
- Brown or orange stains coming from cracks or appearing on tiles.
- Straight, repeated cracks following the line of the bars.
- Flaking or bulging render or concrete.
How small cracks become large ones
A small crack starts as a thin line in grout or render. Left alone, water enters it and each expansion cycle widens it a little. Water then weakens the membrane, then reaches concrete and steel. The crack turns from a cosmetic issue into a leak path and then a structural problem. How long this takes varies, but the direction is the same unless someone intervenes.
Repair according to severity
| Level | Description | Suitable repair |
|---|---|---|
| Minor | Hairline cracks in grout or render, no leak | Clean and fill with flexible material, regrout, balance water |
| Moderate | Deeper cracks, limited leak, hollow tiles in one area | Drain or lower level, open and repair crack, re-waterproof locally, new tiles |
| Severe | Widening cracks, visible rust, sinking surroundings | Engineering assessment, soil treatment if needed, steel and concrete repair, full re-waterproofing |
In severe cases fixing the crack is not enough. The cause must be fixed: stop the leak, treat the soil, protect the steel, then rebuild the protective layers. See structural cracks and when they require draining.
Stopping the chain early
- Balance water regularly, with pH roughly 7.2 to 7.6.
- Watch the level and bucket-test any unexplained loss.
- Regrout failed joints before water gets behind tiles.
- Never leave the pool empty in the sun.
- Check surroundings for sinking or damp and photograph existing cracks periodically.
YAM Pools provides an engineering inspection to identify the cause and severity of cracks, proposes the right repair in a written quotation and carries it out under engineering supervision with a written warranty on workmanship and waterproofing. We serve Riyadh and all Saudi cities.
Frequently asked questions
Can neglect alone crack a pool?
Neglect opens the way for water to reach waterproofing, soil and steel, which are the direct causes of cracking. It is an indirect but very common cause.
What do brown stains on tiles mean?
They can come from metals in the water or metal objects, but if they come out of a crack they may signal rusting rebar, which needs engineering assessment.
Do cracks in a neglected pool mean rebuilding it?
Rarely. Most cases are handled by renovation and re-waterproofing. Rebuilding is only for very extensive structural damage.
How do I protect a pool I will not use for a long time?
Keep it full with light, regular care of water chemistry and filtration, and watch the level. That is better than leaving it empty or neglected.
