Flexitec Primer 5kg

Flexitec Primer isn’t a general purpose primer and it isn’t used everywhere — it’s applied only where the system requires it.

On porous mineral surfaces, the primer regulates absorption and prepares the substrate so the Flexitec resin can cure and bond correctly.

On timber decks (OSB3 TG4), the primer is not applied across the full surface. Instead, it is used specifically for reinforcing board joints, where movement and joint definition need to be controlled before the main system is installed.

Used correctly, it forms an essential part of a compliant Flexitec installation. Used incorrectly or skipped where required, it can compromise performance.

Primer Essential

• Concrete and screed
• Brickwork
• Porous cementitious substrates

Primer Recommended

• Bituminous felt
• Asphalt

Timber Decks

• OSB3 TG4: primer used for priming board joints only

Primer Not Required

• GRP substrates

Special Substrates

• PVC single-ply membranes and existing liquid coatings: adhesion tests required to confirm suitability and primer selection

• Applied by roller or brush
• Used with Flexitec powder hardener
• Hardener percentage varies with temperature
• Typical cure time: 30–60 minutes
• Primer should be over-coated within 7 days

On OSB3 TG4 decks, the primer is brushed firmly into the board joints, ensuring full penetration before reinforcement or coating takes place.

Coverage varies depending on surface texture and porosity:

• 4–6 m² per litre
• 3.5–5.3 m² per kg

Rough or highly absorbent surfaces will reduce coverage, so allowances should always be made when ordering.

Flexitec Primer isn’t something you throw at every surface, but where the system calls for it, it’s essential.

Used on mineral substrates, it prepares the surface properly. Used on timber decks, it does one job: reinforcing board joints where movement matters.

Apply it where required, skip it where it isn’t — that’s how the Flexitec system delivers consistent, long-term results.