What does paving primer do?

Paving primer creates a strong bond between the bedding mortar and the underside of the slab, reducing the risk of movement, cracking or debonding over time.

Do I need primer for porcelain paving?

Yes. Porcelain is non-porous and requires a slurry primer applied to the back of each slab to ensure proper adhesion to the mortar bed.

Can I lay paving without slurry primer?

While some natural stone may bond reasonably well without primer, best practice is to prime all slabs before laying, as this significantly improves adhesion and long‑term performance. Porcelain in particular is highly dense and low‑absorption, meaning it will not bond effectively to bedding mortar on its own — without primer, slabs can be prone to movement and future failure. Using a quality paving primer, such as a polymer‑modified slurry like Pro‑Prime applied to the back of each slab, creates a strong bond between the paving and the bedding mortar, helps prevent staining and efflorescence, and supports a reliable installation that meets recognised standards.

What’s the difference between paving primer and adhesive?

Paving primer improves the bond between slab and mortar. Adhesive is used to fix paving or tiles to a solid base. Outdoor porcelain installations typically require correct priming alongside an appropriate bedding method.

How do I apply paving primer correctly?

Mix the primer to a smooth, slurry consistency and apply an even 3mm coat to the back of each slab and the bedding layer immediately before laying. Ensure complete coverage with no gaps or dry spots. Using a suction cup can help hold the slab in place, allowing you to reach all edges easily.

When should I use a paving adhesive instead of mortar?

Adhesive is typically used for bonding to concrete bases or overlay systems. For full patio installations, a full mortar bed with primer is generally recommended.