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	PHL Binder	3/8" (1 coat)	65 ft²
Brown Coat	PHL Binder	3/8" (1 coat)	75 ft²
Finish option 1	Lime Stucco Coarse	1/4" (1 coat)	50 ft²
Finish option 2	Lime Stucco Fine	1/8" (1 coat)	100 ft²
Sealer (optional)	Breathable Sealer	–	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	Sand Finish	1/8" (1 coat)	100 ft²
Finish option 2	Stone Finish	1/16" (1 coat)	250 ft²
Sealer (optional)	Olive Oil Soap Sealer	–	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 support@earthausplaster.com
Technical consultation: Earthaus technical consultation