Fibreglass (GRP — glass reinforced plastic) baths and shower trays are among the most repairable bathroom products. Despite having a reputation for being fragile, GRP surfaces respond extremely well to professional repair — chips, cracks, crazing and delamination can all be addressed, often achieving results that are virtually invisible to the eye.
What Is a Fibreglass Bath or Shower Tray?
Fibreglass (GRP) baths and shower trays are manufactured by layering glass fibre matting saturated with polyester or vinyl ester resin, then applying a gelcoat finish layer. The result is a lightweight, mouldable product that can take almost any shape — which is why GRP is used for complex shapes, walk-in baths, low-profile trays, quadrant enclosures and bespoke sizes. GRP should not be confused with acrylic (which is vacuum-formed sheet plastic with no glass fibre layer) though the two are sometimes confused by homeowners.
Common Fibreglass Bath and Shower Tray Problems
Gelcoat Chips and Impact Damage
The gelcoat surface layer of a GRP bath or shower tray chips when hit by a hard object. A chip exposes the underlying glass fibre laminate and typically appears as a bright white or pale mark. Professional repair fills the chip with colour-matched gelcoat materials, texture-blending to match the surrounding surface.
Cracks Through the GRP Laminate
True structural cracks through the GRP laminate — caused by inadequate support, point loading, or impact — require more involved repair. The crack is widened, cleaned, filled with compatible GRP repair material, and refinished. For cracks resulting from inadequate support under the tray, addressing the support issue is essential alongside the surface repair, or the crack will recur.
Crazing and Surface Cracks
Fine networks of surface cracks (crazing) in aged GRP are a common sign of gelcoat degradation over time, UV exposure (on exterior GRP) or surface movement. These can be consolidated, filled and refinished to restore the surface appearance.
Delamination and Flex
Where the GRP laminate has delaminated — allowing visible flex when weight is applied — the repair involves consolidating the delaminated area and where necessary adding reinforcement from beneath. This restores structural rigidity.
Star Cracks at Waste Outlets
Star-pattern cracking around the waste outlet of a shower tray is extremely common — usually caused by insufficient support directly under the waste point. Repair addresses the star crack and we’ll advise on additional support if it’s the underlying cause.
GRP Repair vs Replacement
A GRP shower tray replacement requires removing the enclosure, sourcing a matching or compatible tray, plumbing disconnection and reconnection, and retiling if the surround is tiled. Professional repair typically costs £150–£350 and is completed in a single visit. Replacement typically costs £400–£1500+ including installation. For isolated damage, repair is almost always the better choice.
Get a GRP Repair Assessment
Send clear photos of the damage — close-ups and a wider shot showing the surrounding area — for a free assessment and quote.
