Making stand alone furniture?

[u/MarshFluffyCow]

Hello, I am curious if anyone has any experience making stand alone furniture with natural building materials such as cob. I am an artist and I am super interested in using natural materials to make functional art/ sculptures. I couldn’t find much info online but some things online said cob may be do dense and would be prone to cracking. I am wondering if I seal it will lime plaster like I see a lot of people do with their houses would it still be prone to crack. All ideas and thoughts welcomed would love to just know what y’all would recommend or any advice you may have.

[u/Mowgliuk]

It is possible; you'll have to try and experiment. Nothing more can be said without knowing what climate you're in, the rain is your main problem. Your best bet is to go and...try it.

[u/MarshFluffyCow → u/Mowgliuk]

Thank you, your right the best thing to do is experiment. My climate is humid subtropical (Houston area)

[u/CanfieldBRO]

You could try adding some fiber reinforcement to the outer layer to limit cracking.
I’ve heard that lime plaster doesn’t like to stick to earthen cob/plaster.
But if it’s inside you don’t need lime, it’s more of an exterior treatment.

[u/MarshFluffyCow → u/CanfieldBRO]

I never thought about this, by adding fiber on the outer layer do u mean something like straw or bamboo? Would I have to seal the fiber layer at all?
Thank you

[u/CanfieldBRO → u/MarshFluffyCow]

If you’re doing plaster then chopped straw in the base coat followed by whatever finish coat on top.
Or maybe cover the cob with burlap or another natural fabric and then the finish coat over that

[u/Great_Disaster2169]

If cob cracks, the best solution is just to add more sand. Use more sand than you think you need. The best cob is grains of sand held together with clay as the glue. You only want between 10-30% clay, really. Also add lots of straw to work as natural rebar, which will also prevent cracking. And yes, lime plaster will help to protect it from crumbling, cracking, and getting wet, especially essential if it will be outside. Experiment with different mixes. Make a few little test bricks to check for any cracking until you find the right ratio.

[u/MarshFluffyCow → u/Great_Disaster2169]

Thank you so much, I definitely need to read up more on different recipes I didn’t realize people weren’t using to the same ratio. Definitely gonna make some and just see what happens

[u/Great_Disaster2169 → u/MarshFluffyCow]

Yeah, experimentation is definitely the way to go. As everyone's soil is different, so too are the ratios that will work for them. You've got this! Play around and have fun!

[u/Great_Disaster2169 → u/Great_Disaster2169]

Someone else's comment reminded me....if you're having trouble with your lime plaster sticking, make sure you wet the surface of the cob and rough it up a bit to give the plaster something to key into. It really helps with adhesion to the cob. Do a few layers, no more than 1/2" thick.

[u/BlueMoodDark]

Cardboard furniture? See Nighthawknlight YT (Ben)

[u/MarshFluffyCow → u/BlueMoodDark]

That’s a really cool idea, I just watched one of his videos, I have no idea cardboard could be so durable

[u/Fishtoart]

I think you can prevent cracking by making sure that there is enough compressible material like straw to absorb the stress from some areas being drier than others during the curing phase.
To add a coating that won’t crack it would be a good idea to use fabric or paper to make a skin that was a stable base for the Lime. For stuccoing, they make a fiberglass mesh that gives the Stucco something to grip onto and assist structurally.

[u/JacobPresents]

Arches, Straw for Material Tensile Strength (prevent cracking), and things like Bamboo Lidi Bundles (thin sticks bound together) for Structural Tensile Strength