Earth bag root cellar

Built an earth bag root cellar this past summer. It took the better part of 4 months to complete working a few hours here and there.

We used 22 inch wide bags and 2 strands of barbed wire mortar between every row, two of us were able to lay 2 to 3 rows a day when we worked at it. Our water table is fairly deep, so other than making a large umbrella of poly, we didn't worry too much about French drains and such, although we did dig a sump pump pit just in case.

For the door we made the frame out of 8x8 beams and butted the earth bags against it. Other than swelling a bit from moisture, there have been no issues.

The roof was built with power poles laid across and roofed over with plywood, tin and insulation covered with poly to create a water proof barrier.

Stairs and a top side door were built of pressure treated lumber, and the whole thing was covered in 2 feet of dirt. All in all, it has been up and running since the first snow and it has kept everything at a steady 4 to 2 Celsius the whole winter.

Here are a few more pictures.

And a few more

It looks great! i was just wondering where you are located and if your low temperatures this winter are similar to mine.

We are located in south western Manitoba, Canada. It has been colder than normal this year.

Before I started digging, I asked a few of the older folk in the area how deep to dig in our climate. One old timer who seemed to know most told me to dig it as deep as I was tall.

Rob Ketel wrote:We are located in south western Manitoba, Canada. It has been colder than normal this year.

Before I started digging, I asked a few of the older folk in the area how deep to dig in our climate. One old timer who seemed to know most told me to dig it as deep as I was tall.

On the average winter I would have more favourable conditions. Thanks for your post.

How will you keep vermin from chewing their way in ?

What a great visual explanation of an extremely useful process, especially for really cold climates. Great post! Here in PNW wet side they don't work quite as well, but an excellent how to. A hole in the ground in the winter here gets filled with water. Ours have to be above ground, but one could build a PNW wet side version above ground.
John S
PDX OR

Vermin would have to dig through 2 feet of soil, get past the vicious attack kittens and chew through 6 inches of door.

I just looked at this and the other root cellar thread. Glad to see that it's been done and they are working! I plan to build a root cellar here this year. We live on a south-facing slope, and will dig into that. It will be a learning experience for building an earthbag house later, on my other lot.

Kathleen

Thanks for posting this. I hope to do this in a year or two.

Thank You Kindly,

Topher

So it's spring now, and things are holding up really well in the cellar. We had a bit of settling and the door frame swelled a bit, so we had to remove the door and take 3 inches off the top and shave the sides. Even without a French drain there has been no moisture coming in through the walls and no swelling of the walls. Temps have remained from 2 to 4 c all winter and have risen to 7c this spring.

Thank you for this post, I plan to build a storm/ root cellar but I will be going down into bedrock since it is within 3 feet of our soil surface.

Hi!
Now when some years has past, how is it doing?
I'm planning to build one my self. But when I spoke to the manufacturer of the bags, they said that the bags won't last past 6 months. For me it sound weird.
It's poly bags so..
Ronny from Sweden

Ronny, the short lifespan is for bags exposed to sunlight.  As long as you cover the bags as quickly as possible, they should last for many years.

Kathleen...
You probably right.
I have Google it but can't find anyone how has done any follow up on how they doing in the long run.

Don't want to do all the work if its just holds up a couple of years.

Earth bags are supposed to be either covered with earth or an earthen plaster. When covered by one of these methods the bags will last quite a long time, at least 10 years minimum.  

Yes, covered with a 'breathable' earth or lime plaster the poly bags will last. Some of Cal-Earth's super adobe domes are still in perfect shape after 25 years.
Non-breathable cementacious covering can cause problems.

Thanks for the experience feedback!

How did you make the roof?

How do you reckon would such an underground earthbag cellar fare in more wet climates (west Europe) ? (VS bags decay & wet dirt cover weight) ?

Thanks again.
Berteh

Ronny Björling wrote:Hi!
Now when some years has past, how is it doing?
I'm planning to build one my self. But when I spoke to the manufacturer of the bags, they said that the bags won't last past 6 months. For me it sound weird.
It's poly bags so..
Ronny from Sweden

Hey Ronny!
So it’s been 7 years since we built the root cellar and it is holding up extremely well.  It keeps the root vegetables good well into the next summer, the earth bags are holding up very well, and it keeps the beer cold.

Things I would do differently if I were to do it again? I would make a top cap out of concrete approximately 10 cm deep. This would prevent the roof from settling as much as it has. I would also make the cellar bigger.

As to how we built the roof, we laid cedar logs across the top, pressure treated plywood on top of that and covered it all in tin roofing. Then we placed plastic sheeting on top of that and covered it in 2/3 meter of dirt.

Our's is pretty large, 8' wide x 10' long main hall with an octogon room at the end. Roof was built by making a 2x4 frame and covering it with metal roofing that extends past the outer edge of the bags. The exterior off the bags is covered with a membrane (including the roof metal). We used a fiber reinforced cement 8"  thick over the metaal roof then covered that with 10" of soil.

It's great that you gave a followup report like this.  I wish more people would give updates a few years down the line.  Thanks!

Do you have a youtube channel?  I feel like I've seen this root cellar on youtube.

There's a YouTube channel by a couple who moved up to Alaska to homestead. They had a market garden in Oregon but are learning about the different environment they are in now.
They built an underground earthbag cellar last Summer, successfully used it for a Winter... and in their last video they are filling it in with gravel.
I feel that one of the reasons why their experiment failed was because of the shape of the walls. Round would have been better. Domed would have been bombproof.

When you design the roof of earthbag, cob or rammed earth, there has to be enough height so the roof can support the combined weight of all the roof materials to prevent collapse. I used an arch for the hall and a conical shape on the octagon, so far I have no problems.

Chris Sturgeon wrote:There's a YouTube channel by a couple who moved up to Alaska to homestead. They had a market garden in Oregon but are learning about the different environment they are in now.
They built an underground earthbag cellar last Summer, successfully used it for a Winter... and in their last video they are filling it in with gravel.
I feel that one of the reasons why their experiment failed was because of the shape of the walls. Round would have been better. Domed would have been bombproof.

https://www.youtube.com/watch?v=Ss2AaCHHNpc

I cringed so hard watching them build their root cellar. First off, the bags were too small for underground use. They should have used 20 inch bags or wider.
Second, all the straight lines in an underground setting. Round or curved walls are what give you your strength. Think arches.  
Third. They failed to take into consideration the water table. This is where local knowledge comes into play.  Hydrostatic forces aren’t something to mess about with.
Fourth. Using poplar as an underground building material. Just don’t. Poplar rots. Quick.

There are a few more things I could comment on, but they gave it the good old college try.

I cringed too, when I watched the Simple Living Alaska couple build their root cellar but they only took a couple of weeks to build theirs, whereas we took two years (seasons) to complete ours. Ours is about 20ft circular and just 6ft high. We used fine gravel for the fill and it seemed to tamp firm enough. I researched and tested several types of bag fill materials but finally just went with what I could easily access, with some reassurance from Owen Geiger's website. We placed our Groovy Yurt on top with 8" of styrofoam as the yurt floor/cellar ceiling. It's been 2 years and all is good. We still need to finish berming up around the earthbag walls (they are protected from sun) and I want to incorporate some styrofoam into the berm to keep summer heat from warming the cellar. Winter lows in the cellar have dipped to 0deg and summer/fall highs have stopped at 8deg C.  

Hi,

Thanks so much for sharing.

I'm wondering how you deal with drainage from snowmelt and rain. If the root cellar is below ground level, how do you keep your stored goods dry when the ground is saturated with run-off?

Also, is the roof strong enough for people to walk over it? Particularly kids, who find mounds irresistible to climb...

Hi Ivana,

Welcome to Permies.