Go back to article: A sustainable storage solution for the Science Museum Group

The advantages of using hemp-lime concrete

The sustainable credentials of hemp-lime are substantial: renewable, recyclable, potentially sealing up enough carbon dioxide to produce a negative carbon footprint in construction (Lawrence et al, 2012), but the crucial benefit of using hempcrete for museum storage is its hygrothermal – heat and moisture – buffering behaviour. Its low thermal conductivity and good heat capacity provides excellent insulation. Its water vapour permeability, high moisture transfer and storage capacity moderate the humidity of the ambient environment and provide the crucial consistency of environment that objects need.

Hempcrete has a range of building uses from roof insulation (low density) to walls (medium density) and ground slabs (high density), produced by varying the proportions of binder, hemp and water. Different densities have a significant effect on the movement of heat and moisture through the material, with lower densities being more porous, which results in lower thermal conductivity and therefore better insulating performance (Barclay et al, 2014). There are good connections between the pores, which make it highly permeable and able to absorb moisture and sound. Hempcrete’s overall buffering effect on indoor RH has been shown to improve respiratory comfort, skin humidity and perceived indoor air quality (Collet et al, 2013). Moisture buffering also reduces condensation and mould growth, decreasing the need for ventilation and cutting energy costs (Colinart et al, 2013; Latif, 2014). Despite low density hempcrete requiring a load bearing structure, its benefits make it a very attractive material for constructing museum storage.

Figure 13

Black and white photomicrograph of the interlinked pore structure of hemp shiv

Interlinked pore structure of hemp shiv (Photomicrograph x500)

Component DOI: http://dx.doi.org/10.15180/150405/009