Black Forest Zendo plastering

by Mathieu

After finishing the ceiling it was time for the plasterers to do their work. We contracted the local company Glück to do the plastering for us.


We used Claytec plaster for the whole project and did not bother to mix our own. Economically it didn’t make sense mixing our own clay plaster as we normally do and besides it would be very difficult to match the quality of the Claytec plaster. It depends on the project and the purpose but here it was certainly better to work with a ready-to-go quality product.


It can be challenging to find plasterers who are experienced with clay plaster and can work cleanly around the finished carpentry work. In Japan working cleanly and keeping the construction site orderly is the norm but in Europe that is not always the case. I was happy to see that the plasterers worked very neatly. I didn’t expect anything else, I visited some of their previous job sites and ensured that that their work was up to the standard we where looking for.


The plaster is build up in three layers with a jutte cloth in between after which a finish layer is added of less then 3mm. The finish is a white clay-plaster mixed with large grained sand to add texture. It was the client who chose this finish out of many samples.

We used the Yosima Claytec finish plaster that comes in wide variety of colors and textures. In Japan the common finish coat for plastering temples is shikkui, a lime plaster that is troweled endlessly to a perfect smooth and shiny surface. It takes tremendous skill to get this kind of finish to look decent since the slightest mistake or unevenness will show. What we used here is more forgiving. Glück did really good work and we are pleased with the result.


The humidity in the room changed from very dry, 20% because of the floor heating that was difficult to control at the time, to 94% because of the enormous amount of water that is mixed with the clay. It was the perfect test to see how the ceiling boards would hold up. (see the previous post here) The Western Red Cedar boards are fastened in a way that they are able to expand and contract with humidity. If this is not taken into account or if the fastening system is not applied properly you certainly end up with boards that are cracked right down the middle. I was happy that after the plaster had dried and we continued to install the tan tatami platforms I couldn’t find a single crack anywhere.

Stay tuned for the final push..


© All the pictures in this article where made by Jonas V. Nottbeck and are protected by copyright.