Homesteading Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
7,100 Posts
Discussion Starter #1
After observing sandbag construction in VN, why can it not be used here for structures? A mix of builders sand and cement will eventually harden to stone like toughness. If you were to place steel pins (rebar - vertically), would this not be adequate for wall construction?
 

·
Registered
Joined
·
11,300 Posts
Bink said:
Ive been to the calearth site and seen his buildings,they are very impressive.To get it approved for code they chained 2 dump trucks to one,and tried to pull it down.Couldnt pull it down,now code approved in Hesperia.They are also building a museum at Hesperia Lake.Its like a sausage tube filled with cement then coiled around and around to make walls.They also used a tube going around the Lake for erosion control.The guy really has a great system.
BooBoo
 

·
Premium Member
Joined
·
1,274 Posts
I've looked at most alternative building methods and like the monolithic more than most. There are certainly some dynamic homes to view.

I didn't like the marketing of the monolithic domes because of the amount of money up front. There is a lot of detail omitted from the websites so it seems you have pay to get it.

Although I prefer the monolithic designs over sandbag designs, the sandbag approach is better for a do-it-yourselfer. You could always insulate the sandbag structure the same way the monolithic domes are insulated....but it's expensive to have foam sprayed!!
 

·
Registered
Joined
·
1,599 Posts
I also live in SoCa and have seen the sand bag structures...very impressive! Save all of your feed bags! I thought I would like to start building one for my feed storage using all the feed bags I have been saving.
 

·
Registered
Joined
·
24 Posts
Bink said:
We finally decided to go with a monolithic dome,

which we're in the process of building now.
I would love to hear some more about this. I have been looking into dome houses for about a year or so now and they look very very interesting. Would you mind telling us some more details about your house?

How many SQ FT will it be? Approximately how much is it going to cost, if you dont mind answering that one. Are you thinking of doing any earth sheltering? Are you working directly with the monolithic dome institute or another builder? If you are working directly with the institute, how are they to work with? Are they as helpful as they say they are?

Sorry for all the questions, but there are so few people building with these alternative methods, you have to ask when you can :) .
 

·
Registered
Joined
·
24 Posts
Thanks for the info. If you dont mind being more specific, what is the actual amount it is costing you? I dont know exactly what a stick-built house costs these days, and am just wondering about what the dome costs to build. I understand it is going to vary greatly depending on how far you want to go with the bells and whistles, but I am just looking for an approximation.

I would love to build a dome house, preferably a multi-dome complex, that is completely earth sheltered. I have always loved the idea of living underground. The domes offer a very good solution to the common problems that are inherent with underground structures, namely drainage, insulation, and strength. My only hangup has been I have yet been able to get a realistic number as to what the domes cost to build. :confused: They dont print that stuff on their site ya know!

Also, have you talked to them at all about the durability of the airform? Are you going to be leaving the airform attached after the dome is complete, or are you going to re-surface the dome with something else later?

Thanks again for the info!

P.s. - Are you taking any pictures of the construction? I would die to see them.
 

·
Registered
Joined
·
7,100 Posts
Discussion Starter #9
Still seeking info, links, ect on sandbag construction; there was no part of my question that conserned dome construction.
 

·
Premium Member
Joined
·
1,274 Posts
moopups said "A mix of builders sand and cement will eventually harden to stone like toughness."

I'm not clear on the process here. First of all, sand and cement, without water, in bags, will not harden to stone like toughness. The mix may harden gradually, but it will be low quality concrete. This may be the crux of the problem in your jurisdiction. I seem to recall another posting regarding these structures that said the people promoting them would provide engineering assistance to get zoning approval.

If you were to place steel pins (rebar - vertically), would this not be adequate for wall construction?

This is not a given. Since the concrete is in bags, the rebar would tie them together, but may not be viewed as adequate support for the load on the structure. This is where engineers and architects come into play. If you take a design that has been built in another local, you may be able to take advantage of the engineering work to get it through your own inspector.

While the idea seems dirt cheap, the method applies to the shell. A lot of the cost of the house goes to the other details, like the foundation, electrical, plumbing, heating, interior finish, appliances, doors, windows......

Just what is it that appeals to you in this method???

GObug
 

·
Registered
Joined
·
24 Posts
Obviously the major appeal to sandbag contruction is the cost savings in using dirt and plastic bags for the majority of the structural support. But the major detraction is the extra work involved in finishing the structure. You have to cover both the inside and outside with either adobe, or stucco, which is very time-consuming, and also very expensive if you are not doing it yourself. There is also the issue of heating and cooling the structure. There is no way you will be able to use central air or heat, which may or may not matter to you. Also plumbing and electrical become significantly more complicated...

Another thing that I have thought about with both sandbag construction and the monolithic dome construction, is the installation of plumbing and electrical in the exterior walls... How does this work? What happens if there is a problem with the plumbing or electrical once the house is completed? What are they doing with your place Bink?

Also, great pictures Bink, cant wait to see some more :D. Also, do I have to beg to find out what the dome is costing you? Ok here goes.... :worship: :worship: :worship: Please Bink please, I am begging you!
 

·
Registered
Joined
·
24 Posts
Bink said:
I believe with the electric, some people run two lines & if one goes, they use the other. The plumbing is going to run up through the floor and inside the interior walls, rather than exterior.
Hmmm... Conduit would seem a better solution to the electrical... So you arent going to have any plumbing in any of the exterior walls? That seems to limit the design quite a bit... Hmmm... What happens if something goes wrong with the plumbing underneath the slab? I dont like that very much...


Bink said:
Glad you enjoyed the pics, and check your mailbox! Sent you a PM y-day morning. If you didn't get it, let me know your email addy. Off your knees, boy! :)
:eek: It seems I need to be more perceptive.... Thanks man! :D
 

·
Registered
Joined
·
7,100 Posts
Discussion Starter #15
My idea of a sand bag house is basically a square or rectangle stacked via interlocking method. Here in Florida sandbags are used for parapits around drain culverts at river and road crossings. The bags get so hard that a high powered rifle slug will not split them or leave more than a dent. Some have been in place at least 50 years so far, this looks like a solid permanate wall system. 2 by 12 lumber would frame doors and windows, with spikes driven into the bags to keep them in place. The R value is in the high 60's.

Some of us are not requiring that walls be finished in a traditional manor; after the bags harden you could install furring strips with shims to hang a conventional wall covering if you want to as the money comes in. The appeal is that the walls would be 'bulletproof', high R's, would uphold any roof system you could install. A primeter plate would be anchored via threaded rods anchored within the wall its self. I don't know of any alergies related to concrete, it will not burn, it would be very cheap, could be placed by one person with patiance and not many tools or previous building skills. In that I am a past building and roofing contractor I see no trouble with this consept.

The bags would be tamped once in place into squared shapes and allowed to become solid. It looks like 20 by 20 would be under $3,000.00 materials. And with my limited pension this may be the answer. Sound solider than a tin shed.
 

·
Registered
Joined
·
24 Posts
Well I have never heard of using sandbags in place of blocks, which is what you are basically thinking about. Most sandbag construction is in dome or arch designs, whereby the "structure" of the building is maintained by gravity and not rebar, or stakes.

I am sure it would work fine, but if you are going to go that route, why wouldnt you just go with cinder blocks instead? They are proven and can be had for 15 - 30 cents a piece anyhow... Why risk going with something that might not work out the way you'd expect, rather than something that you know will work?
 

·
Registered
Joined
·
3,476 Posts
This guy's building in Georgia, using cob over sandbag, maybe some strawbale:

http://www.gnat.net/~goshawk/summer2002/index.html

I think he started out with an octagonal structure, but has gone to domes and circles. He's built on it over the years. No rebar, apparently, no furring strips. Seems like an amiable person from his website, you might pick his brains a little.
 

·
Registered
Joined
·
7,100 Posts
Discussion Starter #18
Here, concrete blocks are $1.14 each, laying them is .67 cents each; sandbags are $.45 each, .07 cents to fill; what was your question?
 

·
Registered
Joined
·
11,144 Posts
moopups said:
Here, concrete blocks are $1.14 each, laying them is .67 cents each; sandbags are $.45 each, .07 cents to fill; what was your question?
Heck sandbag thing sounds ok to me what with building materials rising in price so fast last couple years, although I might experiment using it for garage or other outbuilding before doing a whole house. I wonder about R value you gave, but at least it couldnt be any worse than block. Others are thinking conventional looking house. I get that you are talking about rough cabin as cheap as possible which may never be finished beyond that.

I also seem to remember an old TMEN article (think it was TMEN) that stacked the 80# quickcrete bags like block, drove rebar to hold them in place and let them harden on their own. I have a small pile of these quickcrete bags that didnt get used up from a long ago project. The tarp rotted, the pallet they set on rotted, the sacks rotted, there is no rebar, but the concrete from in the bags is still in bag shape and still stacked. Probably not greatest quality concrete, but looks like it will stay in that form for forseeable future.
 

·
Premium Member
Joined
·
1,274 Posts
Moopups,

I don't get your costs.
Where is the cost of the Portland?
Where is the cost of the sand?
The bags cost $.45.
Is it your labor that costs $0.07?


How big are the bags?
What is the sand to cement ratio?

I know you can get sand cheap by the yard, but cement is not cheap. A 94 pound bag costs $8 here in Denver before tax. If your wall is 1 foot thick, each square foot of wall is 1 cubic foot of mix. A very weak mix at 1 portland per 10 sand would cover 7 1/3 square feet or cubic feet. If you could get sand at $10 a cubic yard delivered (not that cheap in Denver), that would be about $10 and change (for the mix of portland and sand) per 7 1/3 square feet of wall. Thats $1.42 per square foot, not counting labor.

Lets say your bags hold 94 pounds. That means 11 bags as above equals an additional 77 cents labor for 7.33 square feet. Labor is about 11 cents per squre foot. Add the $4.95 for 11 bags divided by 7.33 sq ft = $.68 per square foot for bags. 79 cents for labor and bags plus 1.42 for cement and sand is $2.21 per square foot.

If you buy new block and have it laid using your figures, it is cheaper to use block. You can't buy used cement, but can buy used block for 15 cents if you are diligent. I can't believe labor is cheaper to bag all that cement and sand than it is to lay block.

I also do not believe 1 foot of cement equals R60. Cement is a poor insulator.

You're gonna bust your back and your wallet.
 
1 - 20 of 20 Posts
Top