Win a copy of Your Edible Yard this week in the Gardening for Beginners forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • Anne Miller
  • r ranson
  • paul wheaton
  • Pearl Sutton
  • James Freyr
stewards:
  • Burra Maluca
  • Mike Haasl
  • Joylynn Hardesty
master gardeners:
  • Steve Thorn
  • Greg Martin
gardeners:
  • thomas rubino
  • Jay Angler
  • Tereza Okava

What sand for cob.

 
Posts: 14
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hello all we are the start of renovating a stone house and barn in the south of France and want to do as much natural building as possible. We have a few hectares of land which is pretty much pure clay, so happy days that’s the clay part sorted. My question is what sand do I use I figure it’s just standard builders sand. For the interior walls I was thinking about making a frame backed up with plywood, filling frame with cob, removing plywood when dry then finishing  with a natural plaster, for this I assume I need a finer sand.
I’ve kinda answered my own questions, but am I right.

Any advice would be greatly appreciated

Cheers
 
gardener
Posts: 1111
Location: Westbridge, BC, Canada
285
building solar woodworking rocket stoves wood heat greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Chris,    It is a common practice to use sharp sand for making cob. "Sharp" meaning sand that has jagged edges rather than smooth (like beach sand) which is rounded. The reason for this is that when the clay that surrounds the sand dries, it pulls the grains together and the angular edges lock producing a stronger finished product. A magnifying glass can be used to look closely at the sand that you have to see if it is more suitable than another. You can also of course feel the sharpness as well while mixing.
 
gardener
Posts: 6644
Location: Arkansas - Zone 7B/8A stoney, sandy loam soil pH 6.5
1294
hugelkultur dog forest garden duck fish fungi hunting books chicken writing homestead
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Like Gerry says, sharp sand is the sand to use. Usually you can get it pretty cheap, sandblasting sand comes in 100 lb. bags here in the USA, go for a middle of the road mesh size for making the best cob.
Also straw from wheat or barley is far above any hay for making your cob strong.
 
Chris Howard
Posts: 14
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
thanks for the replies gentlemen. so sand for sandblasting is good, what about brick layers sand? Sorry if I'm sounding stupid i just wanna make sure i do it right.
 
Every time you till, you lose 30% of your organic matter. But this tiny ad is durable:
Learn Permaculture through a little hard work
https://wheaton-labs.com/bootcamp
reply
    Bookmark Topic Watch Topic
  • New Topic