A single tile or a small cluster of mosaic popping out of your pool is more common than you'd think in an older Sanur villa. The good news: it is usually a straightforward fix if you catch it early. Here is what causes the problem, whether you can simply glue it back under water, and what a proper repair actually looks like from start to finish.
Why Tiles and Mosaic Come Loose
Bali's climate is hard on pool finishes. Every day the sun bakes the water and the tiles, then the temperature drops overnight. That thermal cycling slowly weakens the adhesive bond behind each piece. In villas built ten or fifteen years ago with standard cement-based adhesive, the bond simply runs out of life.
Sanur sits right on the coast, so salt-laden air settles on everything outdoors. Over time that salt corrodes any thin metal mesh backing behind mosaic sheets and eats into grout lines. Add the rainy season, when water levels shift and the constant humidity keeps the substrate damp for weeks, and you have a recipe for tiles starting to lift at the edges.
Finally, PDAM water and well water both carry minerals that deposit inside the grout over the years. The grout crumbles, loses its grip, and the tile above it becomes unsupported.
- Thermal expansion and contraction (daily heat cycle)
- Salt-air corrosion on mesh-backed mosaic
- Rainy-season moisture weakening old adhesive bonds
- Mineral buildup in grout from PDAM or well water
Can You Fix It Underwater?
Short answer: not properly. You can apply a small amount of two-part marine epoxy around the loose edge as a temporary hold so more pieces do not pop out while you wait for a repair. But a real fix requires the area to be dry, clean, and free of chlorine residue.
If the affected zone is near the pool's electrical fittings—pumps, lights, heaters—do not attempt to drain or work in that area yourself. Switch off the power at the breaker box first, and if you are unsure which circuit feeds the equipment, call a professional before touching anything wet.
A full drain is rarely necessary. In most cases lowering the water level 30–50 cm below the damaged spot is enough to give you working access without draining the entire basin.
Send a clear photo of the loose tile or mosaic (and the surrounding area) on WhatsApp and we will tell you what the job involves and quote it from there.
The Repair Process, Step by Step
Once the water is low enough, scrape away all crumbling grout and any soft adhesive around the gap until you reach solid substrate. A plastic scraper and a wire brush are usually sufficient; avoid angle grinders on mosaic because they chip neighbouring pieces.
Mix a small batch of pool-grade adhesive (more on materials below) and press it firmly into the cavity. Set the replacement tile or mosaic sheet with even pressure, checking that it sits flush with its neighbours. Wipe excess adhesive from the surface immediately with a damp sponge before it skins over.
Let the adhesive cure fully—typically 24 to 48 hours depending on humidity and product instructions—before refilling. When you do refill, run the pump slowly for the first hour so the new bond is not hit by a sudden pressure change.
After the pool is back to normal level, apply fresh grout to the repaired area and allow it to cure undisturbed for at least 48 hours before re-chlorinating the water.
- Lower water 30-50 cm below the damage
- Remove loose material down to solid base
- Apply pool-grade adhesive, set new piece, wipe clean
- Cure 24-48 h, then refill slowly
- Grout the repair, wait 48 h before adding chlorine
Getting the Grout Right
Regular construction-site grout is not designed for constant submersion or salt exposure. For a Sanur pool you want a polymer-modified or epoxy-based grout rated for aquatic use. It resists chloride attack and stays flexible enough to handle daily temperature swings.
Do not add chlorine or any pool chemical into freshly applied grout. The reaction can discolor the joint and weaken the binder. Keep the pool off its dosing system until the grout has fully cured.
In the humid rainy season curing times stretch out. If the forecast shows three days of rain, plan your refilling accordingly rather than rushing the schedule.
Materials Worth Using (and Ones to Skip)
For adhesive: a two-part epoxy or a cementitious tile adhesive specifically labelled for pools and spas. Avoid generic wall-tile glue from the hardware store; it was never meant for continuous water contact.
For replacement mosaic or tile: match the size, thickness, and finish as closely as possible. Sourcing an exact colour match in Bali can take a few days because many older villas used imported Italian or Spanish mosaic that is no longer stocked locally. A technician can usually source close-enough stock from suppliers in Denpasar or Kuta within a day or two.
For grout: a white or light-coloured pool-grade grout will hide minor shade differences better than a dark one. Epoxy grout is the most durable option but requires careful mixing; polymer-modified cement grout is easier to work with and still lasts well in a residential pool.
What to skip: silicone sealant as a 'fix' (it moulds and peels within months), regular construction adhesive, and any product that asks you to mix in chlorine or acid activators on site.
- Two-part epoxy or aquatic-rated cementitious adhesive
- Pool-grade polymer-modified or epoxy grout
- Matched mosaic/tile sourced locally in Bali
- Avoid: silicone, generic wall-tile glue, DIY chemical mixes
Quick FAQ
Questions
Do I need to drain the whole pool for a small tile repair?
No. In most cases lowering the water level 30-50 cm below the damaged area gives enough dry working space. A full drain adds cost and time without improving the result for a spot repair of a few tiles.
How long before I can swim again after the repair?
Plan on at least 48 hours for the adhesive to cure plus another 48 hours for the grout, so roughly four days from start to finish. If the rainy season humidity is high, add an extra day. The technician will confirm timing based on the products used and the weather.
Will the new tile match the old ones exactly?
Often very close, but not always identical, especially with older imported mosaic. A slight shade difference in one or two pieces is normal and usually invisible once the pool is filled and lit. If you want a perfect match, bring a sample piece to the supplier; otherwise the technician will source the nearest available stock locally.
I'll reply with what's needed, a price and when I can come.
