How To Paint Over Fibreglass

Fibreglass looks sharp when new, but gelcoat fades and cracks over time. Standard paint won't stick to bare fibreglass without the right prep. So, can you paint fibreglass? Yes. With the correct primer, fibreglass takes paint well and holds for years. Discover how to paint fibreglass properly, from surface prep through to topcoat.

Can You Paint Fibreglass?

Yes, fibreglass and GRP can absolutely be painted. Gelcoat is naturally smooth and non-porous. That means standard paint has nothing to grip onto. A dedicated fibreglass primer creates the key your topcoat needs. Skip this step and paint will peel within weeks, no matter how good the topcoat is.

How To Paint Fibreglass In 4 Steps

Painting fibreglass is straightforward once you follow the right order:

• Clean the surface thoroughly, removing wax and salt residue

• Lightly key the gelcoat with a fine-grit abrasive

• Wipe away all dust, then apply a fibreglass primer

• Once cured, apply two coats of your chosen topcoat

Skipping the sanding or priming stage is the fastest way to shorten your finish's lifespan.

What Primer Should You Use On Fibreglass?

TA Paints manufactures two dedicated primers for fibreglass and GRP:

• Single Pack Fibreglass GRP Primer: ideal for GRP and fibreglass surfaces that are not permanently submerged, such as above-waterline boat structures, fibreglass roofs, canopies and GRP panels. 

• Two Pack Epoxy Fibreglass & GRP Primer: deal for areas requiring full or prolonged water immersion, such as fibreglass boat hulls below the waterline and fibreglass/GRP pond shells. 

Both apply by brush, roller or suitable spray equipment. Both also prime metal, which is handy for mixed-material jobs like boats with metal fittings.

Which Topcoat Works Best Over Fibreglass?

For boats and marine equipment, our marine paints range is formulated for GRP and fibreglass, alongside steel, aluminium and timber hulls. Epoxy topcoats suit saltwater exposure and chemical resistance. Polyurethane topcoats give better UV protection above the waterline.

Browse our hull paints category for the full range.

For non-marine fibreglass (panels or equipment housings) start with our Fibreglass & GRP collection. Then pair the primer with a topcoat suited to the surface's exposure. 

FAQs

Can You Spray Fibreglass Primer, Or Does It Have To Be Brushed On?

Both TA Paints fibreglass primers apply by brush, roller or suitable spray equipment. Spraying gives a smoother, more even finish across large panels or hulls, and speeds up bigger jobs.

Do You Need To Sand Old Gelcoat Before Priming?

Yes, even a light key with fine-grit abrasive significantly improves adhesion to an old gelcoat. Skipping this step is one of the most common causes of paint failure on fibreglass surfaces.

Is Two Pack Epoxy Primer Necessary, Or Will Single Pack Do?

It depends on the level of exposure. Single pack primer is suitable for general fibreglass projects that are not permanently submerged and is easier to apply as no catalyst is required. Two pack epoxy primer is better suited to marine, heavy-duty and chemically exposed environments, including applications involving full or prolonged water submersion. 

Which Primer Should I Use for a Fibreglass Swimming Pool or Pond? 

For fibreglass swimming pools and ponds, use a two-pack epoxy fibreglass primer. These areas are subject to full or prolonged water immersion, so a two-pack epoxy system is the more suitable choice. 

Get In Touch

Not sure which primer or topcoat suits your project? Contact our team for expert advice tailored to your fibreglass surface. While you're here, explore our full paint range to find the right products for the job.