Plaster tests are done before plastering to decide on the right mixture of ingredients for the current application. The tests are allowed to fully dry and then are inspected for how well they continue to adhere to the bale wall and whether there are any issues with cracking.

Different amounts of clay, sand, chopped straw, horse or cow manure, paper pulp, and wheat paste in a plaster will yield different results. An experienced plaster contractor will understand how to adjust the mix to achieve a strong, durable plaster that will be easy to apply and will be suited to the building’s surrounding climate.