Can Cordwood Walls Be Plastered or Finished?

Surface Preparation for Finishing

Cordwood walls are typically finished with a plaster or stucco coat to protect and seal the logs. Before applying plaster or stucco, the surface must be thoroughly cleaned and prepared. This involves scraping off any excess mortar, sanding the surface to create a uniform texture, and applying a layer of scratch coat to create a bonding surface. The scratch coat should be applied to a thickness of about 1/4 inch (6 mm) to provide a stable base for the finish coat.

Choosing the Right Plaster or Stucco Mix

When selecting a plaster or stucco mix for cordwood walls, it’s essential to choose a mix that is specifically designed for exterior use and can withstand the elements. A mix with a high sand content (around 50-60%) and a small amount of Portland cement will provide a durable and breathable finish. The mix should also be formulated to bond well with the cordwood surface, which can be achieved by adding a small amount of lime or a specialized bonding agent.

Applying the Finish Coat

Once the surface is prepared and the plaster or stucco mix is chosen, the finish coat can be applied. The finish coat should be applied in thin layers, around 1/8 inch (3 mm) thick, and allowed to set before applying additional layers. A natural fiber or mesh reinforcement can be added to the finish coat to provide additional strength and durability. The finish coat should be applied in a smooth, even layer, and any imperfections can be filled with a small amount of joint compound or a specialized filling material.