Forums:

chunked concrete for base?

Posts: 7

Location: Ohio

posted 3 years ago

4
Number of slices to send:

Optional 'thank-you' note:

Send

So, I plan to build my cob house this summer. Its been two years of planning. However, I am caught with a new prospect of having lots of broken concrete to deal with after a drainage pipeline running through the property was redone this past summer. Is it feasible to break it up in 15-20lb chunks and set that as the foundation for the cob build? What issues might I run into with that?

I am brand spanking new here to the forum and giddy with excitement over finding such a cool place to chat with likeminded people!

- - - 𝘸𝘦𝘦𝘥𝘴 𝘢𝘳𝘦 𝘫𝘶𝘴𝘵 𝘶𝘯𝘭𝘰𝘷𝘦𝘥 𝘧𝘭𝘰𝘸𝘦𝘳𝘴 - -

John C Daley

pollinator

Posts: 5669

Location: Bendigo , Australia

512

I like...

posted 3 years ago

7
Number of slices to send:

Optional 'thank-you' note:

Send

Yes and no!
If the broken concrete is set on ground that will not settle, then yes.
If the ground has topsoil etc left it place, then settlement will occur and the cob wall may crack.

John Daley Bendigo, Australia The Enemy of progress is the hope of a perfect plan
Benefits of rainfall collection https://permies.com/t/88043/benefits-rainfall-collection
GOOD DEBT/ BAD DEBT https://permies.com/t/179218/mortgages-good-debt-bad-debt

Douglas Alpenstock

pollinator

Posts: 5520

Location: Canadian Prairies - Zone 3b

1518

posted 3 years ago

3
Number of slices to send:

Optional 'thank-you' note:

Send

Hi Maine. Welcome to Permies! I suspect you've found the right place.

I like John C's approach. Heavy clay could work; sand is tricky; and topsoil is jello. I know that one-man motorized tampers can be rented for jobs like this. But my experience with cob is minimal.

Hang tight. Lots of cob wizards around here. I'm sure they will chime in.

Amy Gardener

gardener

Posts: 788

Location: 5,000' 35.24N zone 7b Albuquerque, NM

551

I like...

posted 3 years ago

3
Number of slices to send:

Optional 'thank-you' note:

Send

Chunked concrete is also called, "urbanite." If you Google "urbanite cob images" you will see many creative ways to use the material for cob foundations. Urbanite is the foundation for the adobe buildings here and was also useful for creating the trough for a rebar-reinforced concrete bond beam or foundation (like knock out block). Have a wonderful experience with your cob building project, Maine Fout!

sow…reap…compost…repeat

Maine Fout

Posts: 7

Location: Ohio

posted 3 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

thanks very much, folks!

- - - 𝘸𝘦𝘦𝘥𝘴 𝘢𝘳𝘦 𝘫𝘶𝘴𝘵 𝘶𝘯𝘭𝘰𝘷𝘦𝘥 𝘧𝘭𝘰𝘸𝘦𝘳𝘴 - -

Douglas Alpenstock

pollinator

Posts: 5520

Location: Canadian Prairies - Zone 3b

1518

posted 3 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Amy Gardener wrote:Chunked concrete is also called, "urbanite."

I had forgotten that. Great word. Thanks!

Mark Brunnr

gardener

Posts: 1240

364

I like...

posted 3 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Yup urbanite can certainly be used as a stem wall to protect cob from moisture in the ground seeping up. Make sure to build that on a proper foundation, perhaps a rubble trench or having that stem wall deeper than your frost line.

The holy trinity of wholesomeness: Fred Rogers - be kind to others; Steve Irwin - be kind to animals; Bob Ross - be kind to yourself

PEP - BB10 Badge (verified skill)
Skill verified by gir bot

Ron Warner

Posts: 12

posted 3 years ago

1
Number of slices to send:

Optional 'thank-you' note:

Send

Not sure how well it will pack but I can tell you snakes . If you can't seal it your making a habitat for them could be I don't like snake

Laura Fox

Posts: 14

Location: Eastern Shore of Maryland

I like...

posted 3 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

The Cob Cottage Company uses urbanite in their buildings. They build on a rubble trench.
In the workshop I attended, they also taught me that, as a monolithic material, a cob wall supports a dry urbanite foundation as much as the foundation supports the cob.

<3 Come healing, come peace.
https://foxseden.wordpress.com/

John C Daley

pollinator

Posts: 5669

Location: Bendigo , Australia

512

I like...

posted 3 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

https://www.cobcottage.com/

Liar, liar, pants on fire! refreshing plug:

Learn Permaculture through a little hard work

https://wheaton-labs.com/bootcamp