This Help Center article is a summary of the official Earthaus Adobe Wall System Guide. Download the full Adobe Wall System Guide (PDF).
Overview
The Earthaus BUILD Pozzolanic Hydraulic Lime (PHL) Plaster System is standardized for adobe construction, but versatile enough for project-specific modifications.
Key Properties:
Specialized formulas made with high-plasticity lime and pumice pozzolan.
Excellent workability, adhesion, and durability.
Highly breathable, allowing adobe to release moisture.
Slow and steady curing supports flexibility during early structural movement.
Exterior System (Adobe Walls):
Layer | Product | Thickness | Coverage |
Scratch Coat | 3/8" (1 coat) | 65 ft² | |
Brown Coat | PHL Binder | 3/8" (1 coat) | 75 ft² |
Finish option 1 | 1/4" (1 coat) | 50 ft² | |
Finish option 2 | 1/8" (1 coat) | 100 ft² | |
Sealer (optional) | – | TBD |
Interior System (Adobe Walls):
Layer | Product | Thickness | Coverage |
Scratch Coat | PHL Binder | 1/4" (1 coat) | 100 ft² |
Brown Coat | PHL Binder | 3/8" (1 coat) | 75 ft² |
Finish option 1 | 1/8" (1 coat) | 100 ft² | |
Finish option 2 | 1/16" (1 coat) | 250 ft² | |
Sealer (optional) | – | 700 ft² |
Adobe Substrate Preparation
Inspect the Walls — Ensure structural integrity; surfaces must be stable and free from dust, salts, and efflorescence. New adobe must be cured and settled.
Dampen Before Plastering — Adobe is porous. Pre-dampen with several light mist coats; the goal is damp but not saturated.
Plaster Stops & Lath — Use plaster stops where plaster terminates. Protect wood with felt paper and cover with expanded metal lath. Recommended: embed fiberglass reinforcing mesh in the brown coat to reduce cracking.
Protect Surrounding Areas — Mask windows, doors, and other non-plaster elements.
PHL Binder Installation Over Adobe
Scratch Coat:
Thickness: 3/8".
While wet, scarify horizontally 1/4" deep for bonding.
Cure 10 days before applying the brown coat.
Brown Coat:
Standard thickness: 3/8".
Cure 10 days before finish plaster.
Sand Aggregate (Mandatory):
PHL Binder requires local sand aggregate:
Scratch coat: 1 bag PHL Binder + 3 × 5-gal buckets sand.
Brown coat: 1 bag PHL Binder + 5 × 5-gal buckets sand.
Applying the Finish Coat
After the brown coat has cured (10 days), apply your selected finish from the system table above:
Exterior finishes (Lime Stucco Coarse or Fine): see the Lime Stucco — Application Guide.
Interior finishes (Sand or Stone): see the Interior Sand & Stone Finishes application guide.
Pigment color and optional sealer are listed in the system table above.
Calculate How Much You Need
Estimate the materials for your project with the Earthaus calculators:
PHL Binder (scratch & brown coats): PHL Binder Calculator — select your wall system in the calculator.
Exterior finish: Lime Stucco Fine Calculator or Lime Stucco Coarse Calculator.
Interior finish: BUILD Sand Finish Calculator or BUILD Stone Calculator.
Technical Support
Product questions: email [email protected]
Technical consultation: Earthaus technical consultation
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