29/10/2026
🚨 POOL OWNERS: IS YOUR FIBREGLASS POOL SHOWING SIGNS OF OSMOSIS?
💧 Blistering, powdery gelcoat or an itchy pool surface? Don't ignore the warning signs!
Over time, fibreglass pool surfaces can deteriorate. One issue pool owners should be aware of is osmosis, which can lead to blistering beneath the gelcoat.
🔬 WHAT CAUSES OSMOSIS?
Water can gradually pass through the gelcoat and into the underlying laminate. When water interacts with soluble materials trapped within the laminate (This is called hydrolysis), it can create an osmotic pressure that draws in more moisture. Over time, this can cause blisters to form beneath the surface.
⚠️ WHAT SHOULD YOU LOOK OUT FOR?
🔹 Small bubbles or raised blisters in the pool surface.
🔹 Gelcoat becoming chalky, powdery or losing its original shine.
🔹 A rough surface that can sometimes feel irritating or itchy against your skin.
🔹 Cracking, peeling or localised areas of deterioration.
These symptoms don't automatically mean osmosis is present, but they should be investigated before the damage progresses.
🧪 WHY WATER CHEMISTRY MATTERS
Incorrect pH, excessive sanitiser levels and prolonged chemical imbalance can accelerate gelcoat deterioration. Maintaining balanced pool water is essential to protecting your pool's surface and equipment.
If gelcoat begins breaking down, loose material and debris can also place additional strain on your filtration system by collecting in skimmer baskets and filters.
✅ HOW CAN YOU HELP PROTECT YOUR POOL?
✔️ Regularly test and maintain your pH, sanitiser and overall water balance according to your pool and chemical manufacturer's recommendations.
✔️ Avoid overdosing chemicals or allowing concentrated chemicals to sit against the pool surface.
✔️ Use a suitable pool cover to help reduce UV exposure, debris and evaporation.
✔️ Inspect your pool regularly for changes in texture, colour, roughness or blistering.
✔️ Have suspicious blisters or deteriorating gelcoat assessed by an experienced fibreglass pool restoration specialist.
🏊 REMEMBER: Osmosis develops over time, and once blistering or significant gelcoat deterioration occurs, correcting the water chemistry alone won't repair the underlying damage.
Prevention is always better than restoration!
At All Class Fibreglass Manufacture, we specialise in fibreglass pool resurfacing, gelcoat restoration, structural repairs and osmosis-related damage.
📣 Take five minutes this week to inspect your pool. Have you noticed any blisters, rough patches or powdery residue? Share your experience below. You might help another pool owner catch a problem early!
