Cob Workshop - Foundation

foundation

It's finally time, what probably none of you have been waiting for! A review of our cob workshop! I'm going to divide the workshop into several posts, from the ground up. I am going to provide all the notes I took from the workshop lectures first, then a summary from our trip and any notes I have to add. If anyone has any questions feel free to ask! First up- foundation! 

Think about piping first!

-a perforated pipe drained to fresh air

-water lines

-drainage below foundation

Recipe for Lime Putty

-2-3 inches of water in five gallon bucket first

-add hydrated lime gradually until greek yogurt consistency

-use builders lime - NOT garden lime

-mix with a paint mixer on low speed to blend

Recipe for Lime Mortar

-1 part lime putty

-1 part coarse sand

-1/3 part grog

-grog is a powdered fired clay used as a hardening agent to set foundation up well

-can be found at most builders supply stores or pottery supply

-the grog can be used in the putty as well, for a harder finish

-lime putty can be stored and remixed indefinitely!

-lime is caustic, so remember to wear gloves, mask, goggles, etc

Rubble Trench Foundation

-dig trench two feet wide by two feet deep or deeper, to the frost line

-lay two inches of gravel below a four inch perforated pipe in a U shape

-fill with gravel and tamp every six inches to set in gravel

-the pipe and drainage allows water to drain from the cob

Rock Stem Wall

-use clean rocks to help sick

-use largest rocks first

-set bottom stones 3-4 inches below grade to give it a little seat

-set the first layer 24 inches wide

-narrow to 18 inches for the next layers

-two stones filled with gravel is okay

Laying Rock

-two stones over one

-avoid vertical seams

-blocks can be set sideways or flat

Pointing Mortar

-used to fill in gaps between outside foundation stones

-same lime mortar and gravel to fill holes

-use a spray bottle to keep all surfaces the same moisture level when applying

-for bigger gaps it helps to  form a ball of mortar and gravel in your hands, then fill the hole

Geothermal Air Conditioning

-4 inch fan inside of non insulated pipe run for at least

  200 feet underground from outside to in the house

-the fan can easily be run on solar power

-in case you don't understand, this means practically free air conditioning!

two layers of stone and gravel

chipping away a piece of rock

two of our instructors (in the orange and stripes) and Josh from New York

one wall of foundation we built

the old wall in the background, and two foundation walls we built

making a strong corner

 In all the reading and planning I had done before the workshop, the foundation always confused me the most. I felt clueless. When we had the lecture and starting putting the rocks together, I was blown away by how simple it was. It's just a gigsaw puzzle with gravel in the cracks! We were working on the foundation for a shop building at the front of the property. There was an existing section of wall and foundation (with cinder-blocks) that was completed in the fall of last year. We continued with two sides of the building, setting the foundation, applying mortar, and then made a wall (that's to come later, I'm getting ahead of myself!)

That's step one of our building adventure!

Check back for more fun- you haven't even seen the mud yet! :)

Until next time,

Angela Kelly