Quick Answer
For effective plastering of straw bale walls, apply a mixture of clay, water, and fibers to achieve a durable and weather-resistant finish, ensuring proper drying time and surface preparation is key.
Preparing the Surface
Before plastering, ensure the straw bale walls are completely dry and levelled. Apply a thin layer of natural fiber-based render, such as a mixture of clay and hemp, to the bales, allowing it to dry completely. This initial render, often referred to as the ‘scratch coat’, helps to create a stable surface for the final plaster layer.
Applying the Final Plaster Layer
Mix a blend of clay, water, and natural fibers to create a workable plaster. Apply this mixture in thin layers, approximately 1-2 cm thick, using a technique called ‘raking and floating’. This involves using a rake to spread the plaster evenly and then a float to smooth it out, creating a uniform surface. Allow each layer to dry slightly before applying the next, typically 30 minutes to an hour, depending on the environmental conditions.
Tips for a Successful Finish
To achieve a long-lasting and aesthetically pleasing finish, ensure the plaster is applied in multiple thin layers, allowing each layer to dry thoroughly before adding the next. This reduces the risk of shrinkage and cracking. Additionally, use a high-quality natural fiber-based plaster, and consider adding natural pigments for color and texture variation.
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