This was our summer project.. A 16x25 cobwood barn. We plan on putting a small rocket-stove greenhouse in front. The warm attached greenhouse, plus the critters' body heat will hopefully keep the barn at a comfortable temperature for chickens, goats and an occasional calf or sick animal. The goal was to build the structure with the leftover cordwood from our house for as dirt cheap as possible. So far we haven't spent more than $500-$600 on it. We also experimented with a few new ideas along the way, using the barn as kind of a test project for load-bearing cobwood walls and a shallow sandbag foundation.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/earthbag2.jpg)
We excavated the site by hand and dug a trench, about a foot or two deep and a couple feet wide for gravel and drain tile. You can see the first course of gravel-packed tires under the sandbags. The bags could have gone right on the ground, but the tires offer a wider footing and I basically wanted to try packing a few of them earthship-style. It's a lot of work, and I wouldn't do it again unless I was building a foundation with nothing and had no bags available.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/earthbag1.jpg)
We wrapped the sandbag foundation with plastic erosion control netting and plastered with a cement/lime/sand mix. We were too cheap to use chicken wire or stucco lath, but the netting was a bad idea for this application.. Too flimsy and too dense to let the plaster key in; perhaps a heavier plastic fence/netting would make a better cheap alternative.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwood-barn003.jpg)
The cob mix was clay, sand, dried and shredded horse manure, chopped straw and some dairy products to improve stickiness and workability.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwood-barn002.jpg)
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn5.jpg)
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn6.jpg)
The rafters are Aspen logs cut off our land.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn8.jpg)
The logs were bolted to 2x4 scabs, which were in turn screwed to a couple rounds of cordwood. This helps to both spread the weight of the roof out on the wall, as well as tie down the rafters.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn2.jpg)
Stackwall corners were something new and kind of fun.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn4.jpg)
The mix tuck-pointed well, in spite of the chopped straw..
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn10.jpg)
Slabwood headers over openings..
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn9.jpg)
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn12.jpg)
Laying down pallet sheathing over the log rafters.
Pros: Free.
Cons: A big pain to get the roof somewhat level and safe to walk on. Hardwood pallets are heavy and defiantly bend each and every nail you try to stick through them.
Pros: Free....
Also, you will notice that the front of the building is sandbags with an earthen plaster all the way up. This is to provide more thermal mass in the south-facing greenhouse back wall, as well as give us more experience with earth/sandbag building.
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn22.jpg)
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn24.jpg)
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/cobwoodbarn20.jpg)
Finally got the pallets up and the slab fascia installed.
Over the pallets, we put down a layer of old carpeting, then a pvc billboard tarp for a waterproof membrane. Another layer of carpet over the plastic for extra protection, and finally a layer of hay bales for an insti-green roof. I imagine we'll seed it in spring..
Here's how it looked this afternoon:
(https://img.photobucket.com/albums/v667/AirsoftAndy/Cobwood%20Barn/snowcoveredbarn.jpg)
Still need to put some windows and doors on..
I found this project exciting because of how cheap it was, and it wouldn't take too much more work to turn it into a warm and cozy cottage! The roof was practically free, minus the billboard and some nails.
Anyway, just thought I'd share. Cheers!
Andrew looks like a very interesting and fun project. Thanks for sharing.
I love it Earnest!
Amazing job!!!!!
Did you buy any of Rob Roys books? You look like you mastered his techniques to a Tee!
What a SUPERB photo diary and building. Thanks for posting.
Although I don't envy you the snow. Don't hardly 'member what knobby tires are used for.
Gonna be cold here tonight brrr... Forecasted to be 67 in the morning ;) Might need to turn the heat on in the car on the commute.
Thanks guys. :) I've read several of Rob's books.. We have transferred a lot of his technique to the cob scene, kinda making a hybrid.
Some people are reluctant to try cob in a cold climate. The advantage of using it as cordwood mortar is that the relatively narrow mortar beds dry fast, and the cordwood wall is a lot more insulating than a solid cob wall.
We had a lot of "green" cob that got good and frozen a couple of times on this project to no noticeably ill effect.
67 is car-window-opening weather, Leo. ;) Actually, I'm kind of impartial about the snow.. It can be really inconvenient at times, but it sure is beautiful and a lot of fun as well!
Very cool project, Andrew. You and family always do such neat stuff.
Thanks for the info on both the good working stuff and the not so good. It all helps. :)
Thanks Glenn--it's always fun to share. I'll letcha know if it caves in or falls over this winter. :)
I doubt you will have a problem with that.
Very attractive with the low sunlight highlighting the cordwood. Nothing like the aesthetics of earth, wood and straw.
Sure the roof is strong enough to hold saturated bales with a lawn on top? After a big rain?
We'll find out. ;) I did some calcs w/ Don P's online tools. The aspen logs range from 6''-8'' in diameter and I believe they're like 20'' apart... 13' span. The bales will get quite heavy as they suck up water. We'll keep an eye on the snow and keep our fingers crossed..
Right. With these things common sense is all we got. I have built several non-engineered, non-permitted buildings and even after all these years I worry when the wind really blows, or it's dumping 4' of wet snow overnight.
Yours look really stout though. A living roof is an really appealing idea.
Looks beautiful, I'm glad we get to go to school on projects like this. I did update the log beam calc earlier this year. It should spit out the same results, hopefully just made it easier to negotiate;
http://www.windyhilllogworks.com/Calcs/logbeamcalc.htm
just being picky with semantics, they're purlins rather than rafters
Your tools are an indispensable reference for me, Don. Just wanted to say "thanks"!
Thank you, I'm glad you can use them. :)
Doing long strings of math was where I always made mistakes. The computer has certainly made it easier for me to try out ideas.
Thanks so much Ernst for sharing on this forum :) Your doing an amazing job combining different low cost materials in a great way. Besides it just looks awesome. esp like the stacked corner .
Did you learn cob just from playing with it and the internet or a workshop ?
Jeff
Just reading and playing in the mud.. In person, I've never actually seen another person's cob besides our own. :)
I think the corners are pretty cool, too. Unfortunately, the greenhouse side faces the road, so it's really not that great looking from a first impression..
any books in particular. I just ordered hand sculpted house b/c I heard this was a good resource.
That's a really great book, I'm sure you'll enjoy reading it.
This is an excellent book on earthbags, with good info about earth plasters/floors, etc.
http://www.dirtcheapbuilder.com/eabutotite.html
doh ... i actually have that earthbag book. I did not think to look in it ( a while since I read it).
:D
Wow, sounds like you're ready to start building your own weird structure out of dirt!
Most of Becky Bee's Cob Builders Hand book is online. You can get the complete book form her or other places I think.
http://www.weblife.org/cob/index.html
http://www.beckybee.net/
Def check that out Glenn (tonight's reading material) thanks for link!!!!!!!!
Yeah once our conventional structure is done. Deb wants a cob oven so I think will be our first cob project. I really love the videos of cobville
http://www.youtube.com/watch?v=7qzX1jUWa_s (http://www.youtube.com/watch?v=7qzX1jUWa_s)
I love organic looking structures...they just feel at home in the setting all nestled in with a green roof. I really want to see how your roof does. Neat idea you had.
What a great, inspiring project :D
I thought I might start my first cob project last summer, a cob oven, but ran out of time before I ran out of things to do that were higher on the priority list.
Did you spike or put rebar in the cordwood in the corners to make them stronger?
That is great! Thank you for posting this. It is very inspiring. I always want to do non stick frame construction but never devote the time. They are very detailed larger pictures than most websites I have seen.
Get a simple roof over your clay oven high enough to not catch fire - it will last forever. Rain from the side is not much of a problem as long as you use enough sand and straw in the cob. Several coats of boiled linseed oil greatly increase water resistance on cob but not sure if it would hold up on a oven or not -may depend on thickness and heat.
Kiko Denzer wrote a great cob oven book - I don't have it though. A link to it
http://www.amazon.com/Build-Your-Own-Earth-Oven/dp/096798467X/ref=sr_1_1?ie=UTF8&s=books&qid=1291131047&sr=1-1
Quote from: Squirl on November 30, 2010, 08:49:18 AM
That is great! Thank you for posting this. It is very inspiring. I always want to do non stick frame construction but never devote the time. They are very detailed larger pictures than most websites I have seen.
Yeah, I'm a fan of big pics... Many hours I have spent researching cob mixes, plasterers, etc, and nothing frustrates me more than a decent article with 1/4'' wide pics... ::)
Glad you liked it!
No rebar... I'm not sure if it would really make it that much stronger, but it would be kind of a pain to install as cob doesn't take real well to hard whacking, especially if the wall isn't fully cured and not real massive.