BUILD Exterior Products Overview

Three Coat Plaster System

BUILD Products | Exterior

Earthaus BUILD products are formulated to support the unique requirements of earthen and bio-based architecture. Designed to function seamlessly with natural building substrates, they provide exceptional compatibility and lasting performance while safeguarding the structural integrity of your project.

For detailed information about the BUILD Plaster System for your specific substrate, refer to:

Exterior Wall Systems

PHL Binder (Pozzolanic Hydraulic Lime)

Use for the Scratch + Brown Base Coats

Made with hydrated lime and pumice pozzolan, Earthaus PHL Binder requires the addition of locally sourced sand aggregate and water.

PHL BINDER CALCULATOR
Size : 50 lbs / bag
Cost: $45 / bag

Coat Thicknesses & Coverage
The standard scratch + brown coat thicknesses are unique to each natural building substrate. Actual coverage may vary based on the condition of your substrate. Please Refer to your Wall System Guide.

Scratch Coat Application: The scratch coat functions to create a mechanical bond to the substrate and give texture (tooth) for the brown coat. The scratch coat is horizontally scratched with a scarifier tool.

Brown Coat Application: The brown coat functions to build the plaster to a uniform level and create the final shape of the walls.

Added Sand Aggregate:
Locally sourced sand aggregate is a critical component: it provides structural integrity, increases the volume of the plaster, and helps to reduce shrinkage during drying. The quantity of sand that is added the scratch + brown coat mixes differs. A thorough guide to sourcing sand is provided in the PHL Binder Installation Guide.

To Order: Use the PHL Binder Calculator to select your substrate + enter your project square footage to calculate the quantity of PHL Binder needed for a project. The calculator will show separate calculations for both scratch and brown coat quantities.

Lime Stucco FINISHES- Fine & Coarse

Two Finish Coat Options

Made with hydrated lime, pumice pozzolan, and carefully selected aggregates, Lime Stucco Finishes require the addition of water and can be pigmented in any standard Palette color or a Custom Color.

Compare BUILD Lime Stucco Finishes

FINE FINISH

Size: 32 lb / bag

Cost: $55 / bag

Coat Thickness & Coverage: 1/8", 100 ft²
Actual thickness and coverage may vary based on the condition of the brown coat.

Aesthetic: Smooth and refined texture.

Application: Lime Stucco Fine Finish is applied as a wet-on-wet, “double backed” coat and is troweled smooth to achieve a fine smooth texture.

Optional Sealer: Earthaus Breathable Sealer

Product Page & Materials Calculator

COARSE FINISH

Size: 32 lb / bag

Cost: $45 / bag

Coat Thickness & Coverage: 1/4", 50 ft²
Actual thickness and coverage will vary based on the condition of the brown coat.

Aesthetic: Sandy texture, versatile finish options.

Application: Lime Stucco Coarse Finish is applied in a single coat and typically finished with a sponge float or skip trowel technique.

Optional Sealer: Earthaus Breathable Sealer

Product Page & Materials Calculator

Color Options

Two Pigment Options: BULK or PIGMENT PACKS

Lime Stucco Finishes can be tinted in any of our 54 standard Palette Colors or a Custom Color. BUILD Projects have the option of selecting bulk pigment or Mineral Pigment Packs in the LIme Stucco Calculators.

MINERAL PIGMENT PACKS

Undoubtedly, the ease of pre-measured Mineral Pigment Packs, one per bag of Stucco, can make a project easier instead of measuring per bag. The downside? Individually packaged Packs are more expensive.

Size: 16g -1000g
Cost: $15 - $35/ pack

BULK MINERAL PIGMENT

Bulk pigment is the more economical option. Measured using a gram scale per bag of Lime Stucco. The standard Earthaus 54-color Palette is made using 15 unique pigments with their own names. If you select a color on the Lime Stucco Calculator, eg Cove, you will see the Bulk Pigment name "Almond" because that is the name of the mineral pigment that is used to make Cove.

Size: sold by the lb (1 lb = 454g)
Cost: $16/ lb

FAQ

Yes — Earthaus offers consultation to help you adapt the BUILD Plaster System for a range of natural building techniques, climates, and project goals. Our plaster formulations are designed to be versatile and modifiable, and we’re happy to suggest adjustments based on your construction method, substrate, or design intent.

However, Earthaus is a materials manufacturer — not a licensed design, engineering, or contracting firm. Any guidance we provide is for general informational purposes and should not be interpreted as engineered system design. It is the responsibility of your architect, builder, or project engineer to evaluate any suggested modifications and ensure they meet the structural and code requirements for your specific location and project conditions.

Any diagrams, product data, or application notes provided by Earthaus are illustrative only. Final design decisions, detailing, and code compliance remain the responsibility of the project team. Earthaus warranties extend solely to the quality and performance of our materials when used as intended and properly applied.

We stand behind our plasters as high-performance, breathable systems for natural buildings—but successful implementation depends on collaboration with experienced professionals who understand your full project context.

Earthaus PHL is a pozzolanic hydraulic lime made with all U.S.-sourced materials, including pumice and hydrated lime. Unlike imported NHL (typically from Europe), PHL is more economical, more workable, and easier to apply — especially for natural building wall systems. NHL can be stronger in some contexts, but it's often less breathable and less forgiving in dynamic wall systems.

To ensure proper curing, allow 10 days between the scratch coat and brown coat, and another 10 days between the brown coat and finish coat. Applying the next layer too soon can compromise strength and lead to a weakened plaster system.
Detailed information about the curing process can be found in the BUILD Installation Guides.

Yes. With proper design details, the BUILD system will perform well in wet or cold climates. Key Design Considerations include adequate roof overhangs, proper site drainage, and the use of our Breathable Sealer to add moisture resilience without sacrificing breathability (the Design Considerations are explained in more detail in the Lime Stucco Finishes Installation Guide).