This article walks through how to apply Earthaus Lime Slurry, from substrate preparation through mixing, brushing on both coats, and optional sealing. It is a summary of the official Earthaus Lime Slurry Installation Guide, adapted for clarity and ease of reference. To view the full document, see the Earthaus Lime Slurry Finish Guide (PDF).
What Is Lime Slurry?
Earthaus Lime Slurry is a breathable, hand-brushed plaster coating that provides an opaque, matte finish with gentle color variation and a soft, sandy texture.
Two-coat system that enhances the natural contours of the substrate and softens edges.
Formulation: hydrated lime, pumice pozzolan, fine aggregates, and <5% acrylic additive for durability.
Color range: 54 mineral pigment colors.
Materials Summary
Form: Dry powder, bagged.
Coats: 2 coats.
Sizes & coverage (actual coverage varies by substrate porosity/texture):
One Gallon: 5 lb, ≈35 ft².
Five Gallons: 25 lb, ≈175 ft².
Color options: 54 colors.
One Gallon: pre-tinted.
Five Gallons: untinted + Mineral Pigment Pack (add during mixing).
Custom colors: Not available.
Pot life (mixed): 14 days covered at room temperature.
Shelf life (dry, unmixed): Up to 1 year stored dry.
Properties
No VOCs, microplastics, phthalates, or toxic additives
Durable and breathable
Excellent adherence and workability
UV resistant and colorfast
Where Lime Slurry Can Be Used
Interior (primed): Drywall, existing painted walls, painted/sealed interior masonry (brick, concrete block, stone).
Interior & Exterior (porous, unsealed, unpainted): Masonry (brick, concrete block, stone) and stucco (lime or cement).
Interior (porous natural): Plaster (lime, clay, gypsum) and earthen substrates (adobe, cob, compressed earth block).
Exterior conditions: Keep off direct ground contact; do not apply on flat surfaces or where water will pool. Protect from freezing until cured.
Weather: Do not apply in extreme temperatures or if rain is expected within 48 hours.
Safety & PPE
Wear dust mask, safety goggles, and nitrile gloves when mixing/applying.
Do not eat, drink, or smoke while using. Avoid skin/eye contact and dust inhalation. Wash hands after use.
Substrate Preparation
Primed Interior Substrates:
Drywall: Level-4 finish, then prime (any latex or PVA primer with 1 cup Earthaus Primer Grit per gallon mixed in).
Existing painted walls: Prime (latex or PVA primer with 1 cup Earthaus Primer Grit per gallon mixed in) before slurry.
Painted/sealed interior masonry: Prime (latex or PVA primer with 1 cup Earthaus Primer Grit per gallon mixed in) before slurry.
Porous Interior & Exterior Substrates (unsealed + unpainted):
Masonry (brick, concrete block, stone): Thoroughly clean (pressure wash or stiff brush + water). Surface must be clean and dry.
Stucco (lime or cement): Remove loose/flaking areas; clean; ensure smooth, dry surface.
Porous Interior Natural Substrates:
Plaster (lime, clay, gypsum); Earthen (adobe, cob, CEB): Stiff-brush to remove loose particles; surface clean and dry before application.
Not recommended: Applying with paint rollers or paint sprayers — rollers leave lap lines/marks; slurry will clog sprayers.
Tools & Equipment
Category | Tools |
Mixing – 1 gal | Cordless drill; Mixing paddle; 2-gal bucket |
Mixing – 5 gal | High-RPM variable-speed drill; Mixing paddle; Two 5-gal buckets; 5-gal paint strainer |
Application | Block brush (mixed natural + synthetic bristles) |
Mixing Instructions
One Gallon:
Add 2 quarts water to a 2-gal bucket.
Add Lime Slurry incrementally while gently stirring with cordless drill + short paddle.
After all powder is added, mix 2 minutes; scrape sides/bottom to ensure full incorporation.
Mixture must be lump-free. Add a small amount of water only if needed.
Five Gallons (with pigment):
Add 3 gallons water to a 5-gal bucket.
Add entire Mineral Pigment Pack; mix 1 minute with high-RPM drill.
Strain pigmented water through a 5-gal paint strainer into a clean 5-gal bucket.
Add 1/3 of the Lime Slurry to the strained water; mix; scrape sides.
Add next 1/3; mix/scrape; repeat until all powder is incorporated.
Mix 3 minutes minimum; mixture must be lump-free.
Add a small amount of water if needed for ease of application.
Application Sequence
Interior — Primed Substrates:
First coat: Apply a single thin layer with a block brush; work slurry into substrate texture. Dry 12 hours. Clean brush.
Second coat: Re-mix and apply same as first. Dry 12 hours. Optional additional coats for specific effects (wait 12 hours between coats).
Interior & Exterior — Porous Substrates:
First coat: Lightly dampen surface; apply single thin layer with block brush; work into surface texture. Dry 12 hours. Clean brush.
Second coat: Re-mix; apply as first. Dry 12 hours. Optional additional coats (12 hours between coats).
Sealing Process (Optional)
Interior — Olive Oil Soap Sealer:
Apply when Lime Slurry is completely dry (minimum 12 hours).
Dilution: 1 part Olive Oil Soap : 8 parts warm water.
Apply liberally from the bottom up; wipe excess and allow to dry.
Exterior — Breathable Sealer:
Apply when Lime Slurry is completely dry (minimum 12 hours).
Brush liberally from the bottom up; wipe excess and allow to dry.
Tips & Common Issues
Maintain a wet edge on primed interior substrates to avoid lap lines.
Fast drying = risk of dusting/poor bond on porous/hot/dry surfaces. Dampen first.
Pigment bursts: Prevent by straining pigmented water before mixing in powder.
Re-mix during application if slurry thickens.
Weather: Avoid extreme temps, rain within 48 hours, and freezing during cure.
Do not use rollers/sprayers (aesthetic defects; sprayers clog).
Storage, Clean-Up & Disposal
Storage (mixed): Usable for 14 days if covered; re-mix before reuse.
Storage (dry): Up to 1 year if kept dry.
Clean-up: Clean tools with water.
Disposal: Do not wash unused slurry down drains. Let fully dry in the container; dispose in trash.
Project Consultation
Earthaus offers technical consultation with experts for project-specific questions.
Still Have Questions?
Email [email protected] or text 1-800-917-2414.