Shikkui is an eco-friendly nontoxic Japanese lime plaster[1]. Shikkui is either made by skilled plasterers or produced by companies as safe and sustainable Cradle to Cradle Certified™ products.[2] Traditionally, shikkui was comprised of hydrated lime, seaweed glue, egg-shells, hemp fibers or straw fibers, and water and has been in use for over 1,000 years.[3] It is mainly used as a protective surface coating or solidifying agent for walls and ceilings in building construction.
This material is reputed to achieve a notable range of traditional and modern finishes, including a full range of Venetian stucco and stone effects. Shikkui finishes allow a thin two-coat application and their elasticity provides good stress-crack resistance[4]. The color and texture of a finishing can be individually customized using a variety of diluted color pigments, but shikkui is typically known for its rustic, earthy aesthetic.
The coatings are highly porous and naturally antiseptic, so indoor air quality is actively improved for healthier spaces. Shikkui coatings are also said to be humidity-regulating, fire-resistant, antistatic (preventing dust accumulation), hypoallergenic, antifungal and mold resistant.[5]
Shikkui surface coatings become harder as time passes, as they are continuously absorbing CO2.
History
- Shikkui was most notably used on castles or storehouses.
- Anti-cracking properties were developed over centuries to withstand earthquakes.
Ecological characteristics
Coming from a rapidly renewable source, it has a low carbon footprint in production, and a low energy consumption in production (89% less compared to baked ceramic tiles); it is fully recyclable or decomposable and its hemp–lime makeup absorbs CO2 in the air.[6] It also captures VOC gasses and odors.
Technical specifications
ASTM Test Data
The Shikkui Surface Coatings have been tested in accordance with the ASTM International standards by accredited testing laboratories in the United States.
• Fire Resistance (ASTM E84)Class A (Type I in other codes)
• VOC Content (ASTM D3960)Zero-VOC material
• Shore D Hardness (ASTM D2240)61-85 (depending on product)
• Mold/Fungal Resistance (ASTM D3273/D3274)Rating 10 (no fungal growth)