Hemplime

Hemplime is a term used to describe a hemp-lime composite material employed in sustainable building. The name combines hemp fibers with a lime-based binder to produce a breathable, insulating substance used for walls, plasters, and blocks.

Composition and production: The material typically blends hemp shives and fibers with lime-based binders such as hydrated lime, hydraulic lime, or lime-putty. Water and pozzolanic additives may be included to improve setting and strength. The mixture can be formed into blocks, applied as a render, or used as infill within timber framing (hempcrete).

Properties: Hemplime is lightweight, thermally insulating, and vapor-permeable, allowing moisture to diffuse and helping regulate indoor humidity. It has a relatively low embodied energy and can sequester carbon during hemp cultivation. Fire resistance varies by formulation but is generally moderate. Durability depends on curing conditions and protection from excessive moisture.

Applications: Commonly used in hempcrete construction, hemp-lime blocks for walls, and lime renders for interior or exterior finishes. It is favored in eco-building projects for its moisture management properties and compatibility with natural materials.

Limitations: Requires proper detailing to manage moisture and prevent water ingress; curing can be slow and depends on climate; availability of skilled installers and suitable mixes may be limited in some regions.

History and terminology: The concept stems from the broader hemp-lime building movement that emerged in Europe in the late 20th century, with various suppliers marketing hemp-lime products under different names, including “hemplime” in some markets.