Fibreglass Boat Repair & Osmosis Treatment

Whatever your fibreglass boat needs

Fibreglass boats are tough, but impact, ageing gelcoat and seawater eventually cause cracks, blistering and osmosis. At Tekne Usta we never settle for a cosmetic fix; we get to the root of the damage, restore structural integrity and then finish the surface so it's indistinguishable from original.

Whether it's a small scratch or advancing osmosis below the waterline, we start with a free survey, then explain in writing exactly what we'll do and why.

Fibreglass work we do

• Crack, break and hole repair — reinforcing impact and structural damage with laminate
• Osmosis treatment — opening blisters, drying, epoxy barrier coat and recoating
• Gelcoat renewal — repairing faded, cracked gelcoat, colour matching and polishing
• Below-waterline structural repair — keel, hull and topside damage

What is osmosis and why take it seriously?

Osmosis is water seeping under the gelcoat and forming acidic blisters in the laminate. Left untreated it weakens the structure. We never rush the cure: we open the blisters and let the laminate dry completely, applying the barrier coat and antifouling only when the moisture level is right. See our osmosis guide for detail.

Price and timing

Fibreglass repair cost depends on the extent of damage, boat length and the type of work. Small gelcoat repairs take 2–5 working days; full osmosis treatment, including drying, can take 2–4 weeks. After the survey we give an itemised written quote — no surprise invoices.

Which damage, which method?

Every kind of damage on a fibreglass boat needs a different approach. The table below sums up the situations we see most and their typical solutions — the exact method is confirmed by the survey.

*Drying time depends on climate and laminate moisture; a firm schedule follows a moisture reading.

Why we don't rush osmosis treatment

The secret to success in osmosis is patience. Applying a barrier coat before the laminate is fully dry traps moisture inside, and the problem returns within a season or two. We don't move to the next step until the moisture reading drops below an acceptable threshold. This avoids doing the job twice — the most expensive osmosis treatment is a half-done one.

Fibreglass, GRP, polyester — are they the same?

In the boating world, "fibreglass" and "GRP" (glass-reinforced plastic) usually mean the same material. In repair, what matters is resin compatibility: choosing a system compatible with the original laminate (see polyester vs epoxy). The wrong resin means a repair that soon blisters.