You can apply Earthaus plasters over old lath and plaster walls once the existing surface is sound, clean, and properly primed. Keep in mind that because Earthaus finishes are applied in thin layers, they will not conceal structural or cosmetic flaws in the underlying plaster.
Step 1: Assess the Existing Plaster Surface
Before application, inspect the existing lath and plaster wall for stability and integrity. The substrate must be structurally sound with no loose, delaminating, or crumbling areas.
Key checks:
Repair all cracks, holes, or missing sections using a compatible patching material.
Remove dust, dirt, and any loose or flaking paint.
Confirm that the surface is dry and free of contamination before priming.
Why it matters: Earthaus finishes are thin, decorative coats. They follow the contour of the existing surface, so any imperfections or soft areas in the underlying plaster will remain visible and can lead to uneven results.
Step 2: Prime the Surface
Once the substrate is sound, apply a high-quality primer combined with Earthaus Primer Grit to create a uniform, textured bonding layer suitable for lime plaster finishes.
Recommendations:
Allow all repairs to fully cure before priming.
Apply primer evenly and let it dry completely before plastering.
Use Primer Grit to equalize suction and enhance mechanical adhesion.
A stable, consistent substrate allows the thin Earthaus finish coats to perform properly, maintaining their visual clarity and durability.
Important Limitations
Earthaus plasters are not intended to serve as a patching or structural repair material.
For uneven or damaged walls, full restoration of the original plaster should be completed prior to applying Earthaus finishes.
Primer and Primer Grit preparation are essential for reliable adhesion on older plaster surfaces.
Questions?
Email [email protected] or text 1-800-917-2414 — our team is happy to help.