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Anyone build an earthbag home close to the city?

 
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I am not neccesarily looking for something that has to be green(sorry), but earthbag buildings do interest me. I want to build a home as cheaply and quickly as possible and this looks like the way to go. I think the area I am building in I could secure a permit, but I will be in an area where weather can dip as low as -30 degrees farenheit. The summer can get pretty hot too. Yesterday it was 90 degrees. First I am asking if connecting to city power and water would be more difficult with earthbags. Second, could two people who havent done the technique pull this off? We are very strong physically and I have done hundreds of DIY projects.
 
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First - are you happy with round? Beginner earthbag is much safer as "round" from what I've read.
Second - are you thinking earthbag dome, or a cylinder with a more conventional roof. Domes are *very* strong and cope with many different natural disasters, but in wet locations, the "roof" part of the dome needs proper treatment to stay waterproof. There are pictures of earthbag cylinders with conventional - often green - roofs. So long as they're properly attached and designed for necessary loads (snow, wind) there's no reason for problems.
Third - I have heard of people building essentially  two layers of earthbags with insulation in between. Then you've got thermal mass inside (a very good thing for both extreme cold and heat) and insulation to keep the temperature of that mass from cooling too quickly. Of course this will be more work and expense, which leads to ...
Fourth - how long do you plan to live in this house? If this is your forever home, I'd put whatever time and effort in that will make it last for longer than you need it. We've got way too many "disposable" houses in North America in my opinion!

I have a sister whose 1950's bungalow was made with concrete blocks faced with bricks and zero insulation. She has to heat and cool it regardless of the weather because the thermal mass helps slow temperature swings, but to some degree just shifts them. This is a long term expense she's had to budget for ahead of other choices. A wise choice in building and energy efficient home up front is essentially permanent savings.
 
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Hello AyeJay and welcome to Permies!

I think you have a wonderful idea to build and earthbag house for yourself. "Dirt cheap" has always been how they have been described financially to build them but definitely high on repetitious labour.
A work party is often a great way to get one built....the more people the better. I think just the two of you would be a great start to get the hang of it then recruit others and teach them what you've learned.

Earthbags provide a lot of mass which is very helpful in moderating heat cycles but not so great for holding the heat in when it gets cold outside. The walls would constantly be trying to suck out all the heat as fast as you can put it in the room.  Coupling earthbag with insulation of some sort would definitely be a huge benefit though to mitigate this from happening.

I have not had any experience with adding water or power to an earthbag building but have done my fair share to a stick frame construction so I couldn't see why this would be any more difficult.
Wires would probably need to be encased in some kind of conduit and water lines would need to be carefully mapped out so that a future nail or screw doesn't puncture a line. Everything gets covered with plaster so its all enclosed.

Kelly Harts website has a FAQ section on earthbag building which covers some information on water and electricity: Earthbag FAQ
Scroll down to "Specific Building Components".

Good luck with your project and ask if you have more questions.

 
AyeJay Jones
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Thank you all for the insight! I must ask, why are square structures seen as more difficult than round ones? I just purchased a book for more information on building but I would like to know. I wanted to do a square structure, not a dome. I planned to make the roof with wood instead of earthbags and have a slanted roof. I just dont like the look of the dome roofing.

Also I do plan on living here many years. If I buy a new house in the future I'll pass this on to my children or my younger sister.
 
Gerry Parent
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I wouldn't say they are more difficult, it more-so has to do with stability. A curved wall is naturally more stable than a straight wall, although it could be reinforced with buttresses or perpendicular walls adjoining it.
 
pollinator
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It seems like you are in USDA zone 3b (-30F). Thats a pretty cold environment. How much insulation do you plan on having.
Do you plan on doing 100% earthbag with a dome earthbag roof or will you go with a traditional timber framed roof. You could also do a cement flat roof.

Assuming you aren't going to do a 100% earthbag roof I like this setup

Stonebag foundation + earthbag stem wall
Insulative haybag/Strawbale walls (I have also heard of rice hull filled earthbags)
Timber frame roof with R-30 to R-50 insulation via foam/EPS/fiberglass/strawbale/etc
 
AyeJay Jones
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After reading the guide on earthbag buildings I am worried earthbags won't be enough to get the level of insulation I need. It gets extremely cold, my walls need an r value of at least 21 which is extremely high. A straw bale home just sounds very unappealing to me. I want to make an earthbag home work, but getting around this issue sounds hard. Has anyone tried putting insulation directly onto walls and then covering it?
 
S Bengi
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If anything was possible what type of insulation would you put directly onto the walls?

Also what do you think of this.

And this

https://permies.com/t/10/60866
 
AyeJay Jones
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That actually looks really good! Is that a hybrid home? And maybe the spray stuff and then use drywall since I want to make a square shaped home anyway. Insulation is the last piece of the puzzle for me so excuse me if that sounds really dumb. Otherwise I'm pretty stumped.
 
AyeJay Jones
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So are you suggesting using straw on the inside of the earthbag walls to insulate the home?
 
S Bengi
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I usually think of all houses as a hybrid. It seems like you don't plan on using a dome earthbag roof, so your house will be a hybrid with framed roof. Most likely your floor will also be a hybrid. So yes to answer your question I am suggesting a hybrid house.

Alright back to the question of insulation. It sounds like you want to add a second non-load bearing insulation wall. Preferable on the outside so the the thermal mass can do it's job of storing heat on the inside during the winter vs staying outside at -30F.

EPS boards+Plaster
The have insulation that comes in the same 4ft by 8ft dimensions as drywall. at 6inch they are super light and provide R-30. You can put those outside the earthbag building and them cover them with some plaster/stucco.

Insulative Plaster
There is papercrete
Then there is cementious foam
And also Air-Krete

 
AyeJay Jones
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Okay, that sounds good. I read that having insulation on the outside makes it so that I have to heat the earthbag walls before the house gets warm. Shouldn't I put the insulation on the inside?
 
S Bengi
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What you have read is correct. The thermal mass means that it will take a "long" time for your house to cool down or to warm up.
You might have heat about rocket mass heaters, they use this effect to help. You might have also head about greenhouses using the mass in fish tank/water tank or the mass in earth tubes to help the temperature.

So this long cooldown/heatup is actual a feature not a problem or bug
And if you can add some winter solar gain for passive heating even better.
Also if you are heating with wood this means you can do one big bulk burn vs numerous small burns every 3hrs.

 
S Bengi
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I wonder what the floor plan for your house looks like? How about this floor plan?
 
AyeJay Jones
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I was thinking a one bedroom for my first, but this floor plan is something else. At first I didnt like it, but I like where it's going. I would probably ditch the greenhouse though to increase the size of everything else.
 
AyeJay Jones
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The floor plan in my head did not even include laundry and mech room I have to figure out what works best for me.
 
S Bengi
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The greenhouse isn't really apart of the house.


With this plan you dont have to worry about the exterior wall and insulation. The house is also heated by the sun during the winter and you can do grey water recycling and grow some vegetables if you want.
 
AyeJay Jones
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It looks awesome, square footage?
 
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AyeJay Jones wrote:It looks awesome, square footage?



Looks like it's right about 1200.
 
Jay Angler
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AyeJay Jones wrote:Okay, that sounds good. I read that having insulation on the outside makes it so that I have to heat the earthbag walls before the house gets warm. Shouldn't I put the insulation on the inside?

Yes, thermal mass takes longer to heat up, and similarly longer to cool down. Currently a compromise is "radiant floor heating" where you insulate the bottom and sides of a concrete floor slab embedded with pipes for hot water to flow through. Heating the "slab" is more efficient than heating "air". Air heats quickly, but doesn't hold any heat, so as soon as the furnace turns off, it starts to feel chilly again. Heating a mass be it floor, walls or dirt under a waterproof "umbrella" such as is discussed in the WOFATI experiments at Wheaton Labs, all provide "slow-release" heat. Depending on how it's done, it takes longer to "charge it", longer to "fill it with heat" but then it keeps the house a comfortable temperature for hours, days or in the WOFATI experiments essentially permanently (humans give off heat, and so do many things we do, like cooking, so the WOFATI is getting heat from that as well as solar gain - the goal is just to not be having to add heat for heat's sake).
 
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AyeJay Jones wrote:Thank you all for the insight! I must ask, why are square structures seen as more difficult than round ones? I just purchased a book for more information on building but I would like to know. I wanted to do a square structure, not a dome. I planned to make the roof with wood instead of earthbags and have a slanted roof. I just dont like the look of the dome roofing.

Also I do plan on living here many years. If I buy a new house in the future I'll pass this on to my children or my younger sister.



You've asked a lot of good questions, as I am also doing in preparation for my first earthbag dome house. Insulation in particular.

The first post asked if this is something two strong, willing people who lack experience can do?  Then you also asked the question above about square vs round.

We're talking about taking tiny, unstable particles of sand/clay and putting them into larger units, then making those units into a home. Without framing.  And you want to know if two unskilled people to do it.

My answer is yes, two unskilled people can do it --  if you build an earthbag dome (bonus for using hyperadobe).  If you build anything besides an earthbag dome, my answer switches to no.

The dome is essentially the most stable, sound, forgiving structure you could possibly hope for.  From eggs to cathedrals, the dome has proven its structural utility for millenia.  If you're trying to get 8 foot high walls with a roof on top, you can spend weeks designing something that is likely to be very frustrating and unstable.  Or you could already be living in your bombproof dome house.

If you build sandbags straight up 8 feet to form a wall, that wall is going to fall, guaranteed.  If you join two such walls at a right angle, they might stay up.  If you build them into a square, it will probably stay up.  I'd say there's a 60% chance you got the walls vertical and stable enough, and a 40% chance that you didn't.  And when a big storm comes by or a tree falls or floodwaters lap up against the base, did you really get each bag directly above its sibling below?  I sure hope so.

If you build sandbags 8 feet up in a curved wall, that wall is much more likely to stand, for much longer than even the right angle example above.  If you complete that curve into a circle?  Suddenly the magic begins.  Where is the weak point?  It is everywhere.  It is nowhere.

That same example goes triple for the roof.  How are you going to join a roof to a square structure?  Lots of ways to do it, but I'll tell you one thing:  None of them are as simple and stable as two people with buckets of mud finishing off a dome and hi-fiving each other, never having a worry or care about whether the roof is going to cave in.

As for electrical, youtube has lots of great earthbag building tips about electrical.  My Little Homestead heavily uses earthbags.   Maybe this one?

As for insulation I have the same questions as you so I'm gonna make a thread for that soon.

Good luck and I really want to hear how it goes for you.  I got overwhelmed with this when I started so I'm just planning it all out now.

 
AyeJay Jones
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I was reading a lot and came to the conclusion that because it gets so cold here I dont think earthbag is the way. I think I will build a polebarn home instead. Then make an earthbag building later on to see how I feel about it. I need an r value of at least 30 to be okay here and with earthbag walls that just doesnt seem possible.
 
pollinator
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AyeJay, glad you bumped this to the top threads so that I saw it. I would concur that earthbag is probably not the best way to go because of the cold. My house is the photos featured earlier in the thread and it is a balecob house. I can't recommend this technique enough as it really is best of both worlds. If you are looking to surpass r30 in your walls, then bales will most likely get you there. There is of course a lot of factors, how tightly your bales are strung and what kind of straw you are using, but generally it is safe to assume a bale wall with plaster is going to get you to that goal.

A balecob house uses that insulation and then throws a massive amount of thermal mass within the envelope. Bitterroot Valley Montana gets up to 100F in the summer and down to about -5F in the Winter. In the two years I've lived in my house, the temperature in the summer gets up to 75F at the highest and with 1.5-2 cords of wood in the winter stays about 70.

My wife and I previously lived in full cob house in the same area and it stayed awesome cool during the summer, but it was a pain to keep warm in the winter. Need that envelope.
 
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