There are many choices for plastering, from earthen plaster to lime to cement-based materials. We could write an entire book about plaster choices, and indeed, people have done just that.

The simplest plaster to use on a straw bale structure is lime plaster. We most often work with Natural Hydraulic Lime (NHL) and Earthaus PHL Binder. Both are durable, easy to apply, vapor permeable, flexible, and well suited to straw bale walls. NHL also has self-healing properties during its early curing period. Earthaus PHL uses hydrated lime combined with a pumice pozzolan and is mixed on site with locally sourced sand.

If you decide to plaster with NHL or Earthaus PHL, be sure to contact us. We have suppliers who will give you a discount on your order if you mention us. You can use the Plaster Discount Request Form or email us at info@strawbale.com. The material is not cheap, so the discount is worth it.

NHL and Earthaus PHL are the lime plaster systems we most often recommend for straw bale construction, and both have become common choices on the workshop projects we work with.