BUILD Plaster System over Exterior Stucco
Earthaus BUILD is an innovative pozzolanic hydraulic lime (PHL) plaster system specialized for exterior and interior application over straw bale wall systems. Earthaus BUILD Plasters are made with US-sourced natural materials and designed to be exceptionally lightweight, providing an all-in-one, high-performance, eco-friendly solution for breathable lime plaster.
Earthaus BUILD Plasters are formulated to support the unique requirements of straw bale construction. The BUILD plaster system protects straw bale walls with exceptional durability while maintaining the ability to breathe, releasing moisture and reducing the risk of mold and structural issues. In addition, the slow, steady strength gain of pozzolanic hydraulic lime can accommodate for early structural movement and has the potential to reduce cracking.
The Earthaus BUILD Plaster System over Straw Bale construction is standardized; however, the materials are versatile and the system may be modified based on the needs of a unique project.
PHL Binder (Pozzolanic Hydraulic Lime) is the base coat foundation for both exterior and interior applications. Sand aggregate sourced locally must be added to the PHL Binder.
PHL Binder (Pozzolanic Hydraulic Lime)
Scratch + Brown Base Coats
Size : 50 lbs
Coverage: 75 ft² / bag: can vary based on condition of substrate
Cost: $45, does not include shipping
SCRATCH COAT | PHL Binder
The PHL Binder scratch coat functions to create a mechanical bond to the substrate and give texture (tooth) for the brown coat. The plaster is horizontally scratched ¼” deep with a scarifier tool.
Scratch Coat Thickness: 3/8"
Cure Time: 10 days
Cost + Coverage: $40/bag, 75* ft²
BROWN COAT | PHL Binder
The PHL Binder brown coat functions to build the thickness of the plaster to a uniform level and create the final shape of the walls.
Brown Coat Thickness: 1/2"
Cure Time: 10 days
Cost + Coverage: $40/bag, 75* ft²
SOURCING LOCAL SAND AGGREGATE
PHL Binder requires the addition of sand which must be sourced locally. Sand aggregate can be sourced at sand and gravel yards, landscape materials suppliers, and stucco and masonry supply yards. A thorough guide to sourcing local sand is provided in the PHL Binder Installation Guide.
Scratch Coat: Three 5-gallon buckets of sand aggregate to one bag of PHL Binder
Brown Coat: Five 5-gallon buckets of sand aggregate to one bag of PHL Binder
*The coverage is the same for the scratch coat and brown coats despite their different thicknesses due to the difference in volume of added sand. In general, coverage can vary depending on the quality of substrate preparation and application of thicker or thinner base coats.
LIME STUCCO
Coarse or Fine Finishes
COARSE FINISH
Aesthetic: Sandy texture, suede from a distance
Application: Coarse Finish is applied in a single coat and is floated with a sponge float to achieve the coarse sandy texture. Lime Stucco Coarse Finish can be pigmented in any Earthaus Palette or Custom color.
Finish Thickness: ¼”
Size: 32 lbs
Cost & Coverage: $45/bag, 50 ft²
Calculate & Purchase Lime Stucco | Coarse Finish
FINE FINISH
Aesthetic: Smooth and refined texture, smooth from a distance
Application: Fine Finish is applied as a wet-on-wet, “double backed” coat and is troweled smooth to achieve a fine smooth texture. Lime Stucco Fine Finish can be pigmented in any Earthaus Palette or Custom color.
Finish Thickness: ⅛”
Size: 32 lbs
Cost & Coverage: $60, 100 ft²
FINISH CONSIDERATIONS
Lime Stucco Coarse Finish can be applied over a rougher finished PHL Binder brown coat. Lime stucco. Fine Finish requires application over a smooth PHL Binder brown coat.
COLOR OPTIONS
Bulk Mineral Pigment or Mineral Pigment Packs
Bulk Mineral Pigment
Sold by the pound ($15), bulk mineral pigment is the economical choice with the trade off being the requirement of using a gram scale to measure bulk pigment per bag or batch.
The number of pounds of Bulk Mineral Pigment for a project is determined based on the number of bags of Lime Stucco in the Lime Stucco Calculator.
Mineral Pigment Pack
Add one per bag of Stucco. Ranging from $15 (lighter colors) to $50 (saturated colors), for some the trade off of the convenience of pre-measured Mineral Pigment Packs outweighs the trade off of cost.
The number of Mineral Pigment Packs for a project is based on the number of bags of Lime Stucco in the Lime Stucco Calculator.
COLOR NAMES vs PIGMENT NAMES
Earthaus Color Palette names are different than Bulk Pigment names. View this link to see a visual representation of our 12 Mineral Pigments and the 54 colors they make.