Calfitice? What and how.

Hi everyone. I recently came across a natural builder using Calfitice as a finish material. I generally understand it is a blend of lime, earth, fiber, and cement. However I am trouble finding a ratio for the components as every video source is narrated in Spanish and I took German in high school instead!

Can someone help me out on this. Seems like a more stable soil cement and I would like to experiment with it on an earthbag structure.


Thank you!

Interesting!

here's a translation of the recipe from this Brazilian site: https://www.semmuros.com/calfitice

CALFITICE RECIPE

– by eng. Luis Carlos Rios Gallego

1 part of white cement or other (CPIII), (CPIV, pozzolan)

2 parts hydrated or pozzolanic lime (the latter is best)

1 part medium sand

9 parts ravine soil (without organic matter), sifted

5 parts water (until it reaches a paste consistency)

5% to 10% chopped fibers (sisal is ideal), up to 4cm long

Test to see if the dough is “done”: after adding the fiber, lift it, which should remain structured without breaking.

Thanks Jane. This is my favorite part of natural building. “Ravine soil” is so unspecific, I love it. I’ll do some tests with my cob soil and post results.

Its my guess 'ravine soil' would be silt.
yes I found this Ravine Soils defined
"What is ravine soil?
The Ravine series consists of moderately deep, well drained soils that formed in alluvium and residuum derived from shale.
Ravine soils are on plains, fans and pediments. Slopes range from 1 to 5 percent."

I Googled, too. The Brazilian ravine soil is terracotta coloured and considered low fertility, but I couldn't find anything In English or that I could translate about the actual composition. We need someone in Brazil to say what " terra de barranco" actually means in soil terms!

In Portugese it means " hillside" soil

Yes. But someone local would be able to clarify if it's sandy, silty, clayey soil. The photos of the ravines there and one article I found about using it to male house paint seem like it could have high clay. But it could equally be sandy, I've seen similar red sand gullies in the outback.

I suspect given that sand is mentioned separately in the recipe, it's most likely to be a high clay content soil. But that's just a guess!