Recipes for earthen plaster abound.  Some recipes use straw, some use manure, some cattail fuzz, and others add lime.  Read a ton and learn, but remember the earthen plaster mix or recipe you end using is your individual choice.  You’ll end up doing a lot of experimenting because the clay soils differ from area to area.  So don’t get frustrated.  Just remember to write it down after you figure it out.

I’ve collected some earthen plaster recipe options.  Most of them provide some instructions on their specific procedures.

Recipe 1

• 3 (five gallon) buckets of sifted sand (sand sifted through a 1/8″ screen to remove pebbles)
• 1 bucket of mixed wet clay
• 3/4 bucket fresh cow manure
• cattail fluff (see fibers in every handful of material)
• 8 cups of wheat paste

Recipe 2

• 4 Parts Clay (presoaked overnight in water)
• 4 Parts Sand
• 1 Part Flour Paste
• 2.5 Parts chopped Straw or Cattail Fuzz (straw cut into one inch lengths)

Recipe 3

This one is for rough coat:

• 1 part creamy clay slip (from site or mixed water and clay)
• 2 parts medium sand
• ½ part fiber (chopped straw)

Recipe 4

• One part clay soil
• Three to four parts sand
• One-half part fine fiber
• Enough water to make the plaster into a consistency slightly wetter than peanut butter.

This is just a small sampling of what’s out there.   Clearly the recipes for earthen plaster differ, so experiment, experiment, experiment.  For mixing the mud, save yourself some pain and get a mixing paddle that you attach to a drill.  Professional mud guys wouldn’t be without this tool.

Time to get that mud slung on the walls. Good luck!

Additional posts you may be interested in:

• Dirt on the walls is a good thing (1)
• SIPs: Strong and Sustainable (0)
• Do you want to toss a gob? Build with cob! (0)