You should use Primer Grit on all non-wet-area substrates before installing Earthaus plasters. Earthaus Primer Grit is a preparatory coating designed to enhance the bond between the substrate and the plaster finish — it creates a lightly textured surface that improves adhesion and workability for Earthaus lime plasters.
What Primer Grit Does
Primer Grit acts as a mechanical bonding layer between the substrate and the plaster. Its fine aggregate texture gives the plaster a consistent surface to grip onto, reducing the risk of delamination or uneven absorption.
Why it matters: Lime plasters require a controlled level of surface tension and suction to bond correctly. Smooth or sealed substrates — such as drywall, painted surfaces, or previously plastered walls — lack the surface roughness needed for reliable adhesion. Primer Grit bridges that gap by creating a uniform, plaster-friendly texture.
Benefits:
Promotes strong adhesion between plaster and substrate
Equalizes suction for more even drying
Reduces risk of surface failure or flaking
Simplifies application, especially for large wall areas
Where to Use Primer Grit
Apply Primer Grit on all non-wet-area substrates before installing Earthaus plasters.
It is ideal for drywall, painted surfaces, sealed masonry, or other smooth backgrounds.
Where Not to Use It
Do not use Primer Grit as a substitute for a waterproofing or vapor-control layer.
It is not required on rough, porous mineral substrates where a natural mechanical key already exists (e.g., fresh lime or cement base coats).
Do not apply in wet areas such as showers or steam rooms unless directed within a specific system guide.
Installer Responsibility
The installer must ensure that the surface is clean, stable, and free of contaminants before applying Primer Grit. All substrate preparation must comply with local building codes and best practices.
Good to Know
Earthaus Primer Grit is formulated for compatibility with all Earthaus lime plasters.
Always allow Primer Grit to dry completely before applying plaster.
Product use and coverage may vary based on substrate type and ambient conditions.
Questions?
Email [email protected] or text 1-800-917-2414 — our team is happy to help.