Restoring Old Root Cellar

I’m in the process of restoring the root cellar built by my great grandpa. As far as I know, no one has even been into it since the early seventies. Aside from 17 wheelbarrows of debris and pack-rat nesting material, a cleanup crew excavated 100’s of clamp-style mason jars and 2 old 400 egg incubators, seemingly heated by coal. They used to be cool, now they’re a bit decrepit. At least the copper tubes may be useful in future projects.

But regarding the cellar, I’m learning a lot along the way, about root cellars, roundwood building, living roofs, and a lot else. I thought it would be cool to post progress here and invite the permies collective consciousness into the journey. Input welcome!

Years ago I reclaimed a root cellar that had been filled with coal ash.  It was quite the experience.  If I remember correctly, the ash ended up on the driveway.  And yes, there were many buried treasures.  Oddly, the timbers holding the roof were in good shape.

John F Dean wrote:Years ago I reclaimed a root cellar that had been filled with coal ash.  It was quite the experience.  If I remember correctly, the ash ended up on the driveway.  And yes, there were many buried treasures.  Oddly, the timbers holding the roof were in good shape.

I would suppose wood ash to be an excellent wood preservation method. Very cool.

First round of pictures.

It is a 10ft x 20ft interior, poured cement covered in earth and lawn. There were two rooms, the front being a storm cellar and the rear storage area behind a partition wall was 2 feet lower. There is a stairwell of cement between two retaining walls. 5 mature trees (mulberry, walnut, and peach) were growing from the sides, but thankfully there are no signs of damage.

First task is to rebuild the stair roof to keep rain and debris out. I’m kind of winging it, using remnants from the tops of Eastern Red Cedar from our mill. First time building a roof of roundwood, so input welcome. My current plan is to clad in billboard canvas and create an earthen roof.

I am curious about the need to take those trees out. Would they have shaded the ground and been useful for their produce?

John C Daley wrote:I am curious about the need to take those trees out. Would they have shaded the ground and been useful for their produce?

I had quite a pause before taking them down. However, the possibility of root pressure against and through the 120 year old cement convinced me in the end.  I have currently left a peach and a mulberry at coppice height while I evaluate the need to take them out entirely. But seeing as how I have a half dozen peach trees and hundreds of mulberry trees in more desirable, non-liability locations, I am leaning toward eliminating them entirely. There is one earthen part of the floor near the bottom of the stairs that has mulberry roots presenting, which is enough reason for me to eliminate - unless I can become convinced they won’t pose a threat to the structure long-term. If you have information on mulberry roots and their uneqivocal habit of avoiding man-made underground obstructions, I would love to hear it!

Looks like you'll have a great Oddball BB submission with this project.  Or Homesteading Oddball would give you even more points...

Isn't roundwood kinda fun?

I think it's awesome that you're rehabilitating this structure and hope you're successful. Our water table is too high in the winter to make an "underground" root cellar, but I would sooo... like to build an earth-bermed one for keeping garden produce longer without electricity.

Beau Davidson wrote:

Looking down from rear vent shaft. I am curious the original purpose of this shaft. Emergency egress, should stair become unusable in a storm event? Warmer storage of fruits?

All of the above? You definitely need air flow for both people during a storm and to stop the build up of gasses given off from some fruits that encourage ripening, and airflow will decrease the risk of mold.
Sepp Holzer has pipes coming in through the earth so that the air temp is stable and it vents up high to get that air flow in his root cellars.
Different fruits and veg respond better to different temperatures with onions and squash liking it warmer, and carrots and cabbages being happy at 32F (0 C).
Some things like it dryer than others also, so the storm-shelter part could possibly have some shelving for things like canning jars which are happy dry, and behind the door, it can be more humid for root veggies (depending on how many people need to fit in for how long!) In many areas storms are getting bigger and longer, so having the basics to stay comfortable seems like good planning to me.

Great job on the round-wood woodworking - and a cute supervisor you've got!

As a Civil Engineer I need to remind you the walls are made of concrete, cement is an additive to concrete.
Not withstanding, those walls do not look damaged at all from tree roots.

The photo of the other outlet is poor, what is it actually showing?

John C Daley wrote:As a Civil Engineer I need to remind you the walls are made of concrete, cement is an additive to concrete.
Not withstanding, those walls do not look damaged at all from tree roots.

The photo of the other outlet is poor, what is it actually showing?

Thanks, John, noted! Concrete.

I’ll grab some better images this weekend. It is essentially a 2-3 foot square shaft, connecting the above ground to a small doorway high at the rear interior wall. Interestingly, this shaft has an earthen floor. Or possibly it goes down significantly deeper than the small passage door. I know it had a hatch over it, as well as an interior ventilation grate. There is also a separate, small 8-inch diameter port immediately in front of this shaft, seemingly a vent from the rear of the cellar. I am uncertain how this functioned, as it has simply been covered with a terra cotta pot fitted to the upper opening as long as anyone can remember.

One thing I’m wondering is if I may need to consider adding air flow vents at the entry door, or in the partition wall between chambers, or if I even need to consider separate dedicated intake and exit points for each chamber. It doesn’t seem to have incorporated intentional venting originally. I have found out that this cellar was designed and construction overseen by a great great uncle who was very knowledgeable, and it seems like they did a bang-up job. So I want to keep with the original function, improving only where modern knowledge, tools, and best practices dictate.

Jay Angler wrote:Great job on the round-wood woodworking - and a cute supervisor you've got!

Thanks Jay! She means business, that’s for sure.

And airflow is a main area of study as I plan the interior - I’m hopeful some folk with some direct knowledge of similar early 1900’s systems can point me in the right direction.

Mike Haasl wrote:Looks like you'll have a great Oddball BB submission with this project.  Or Homesteading Oddball would give you even more points...

Great thought, Mike. Will do!

Mike Haasl wrote:Isn't roundwood kinda fun?

Super fun. This is actually a learning and practice project preceding to a small home addition I want to build this fall with similar materials and techniques.

I think you will find there will be enough leakage around the doors.
Otherwise just monitor it.

Here’s some detail shots of the rear access shaft. It seems it was a later modification, judging by the cement cuts and block retaining walls, as well as the redundancy of the small vent port just in front.

That opening may very well encourage a flow of air through the cellar.
Proof would be if there is no pools of water and mould on the walls.

It's hard to tell from the photos how large it is. Do you feel it is large enough for people to use it as a back-up escape route? I am aware that here in Canada, a number of underground structures were condemned strictly because the law requires two separated exits. It is quite possible that the root cellar was retrofitted when the need for the "storm shelter" purpose was seen as more critical than when it was first built, but to serve both purposes, a back door is worth having!

Regardless, if you're going to be storing food, that opening has to have some sort of "door" ideally with some sort of air control that can be adjusted based on the time of year, and it will need to be vermin-proof!

That rear access may be a great back saver, set stuff in there to store on the shelves instead of humping it down the stairs.
If it’s big enough.

Wow this is amazing! Im glad you're restoring it, most people would just have left it and forgot about it. Good luck on this project!

For the time being, I’ve secured the roof with corrugated plastic sheathing. Still to do is:
1) permanent back hatch roofing
2) entry door
3) intermediate partition wall and door
4) shelving
I’ll get back to this project periodically, and in a more focused way in the winter, after our wee home addition is finished. That process thread is here:
https://permies.com/t/145209/Microhome-Addition#1135152

dang that's one heck go a root cellar, reminds me a lot of fallout shelters people built in the 50's and 60's. can double as a tornado shelter too

We were watching a show on Netflix that’s made in Poland, there was a scene of a church cellar and briefly I saw the same opening in the back wall as yours. I searched old polish root cellars and an image popped up titled old rectory cellar that had one, and one that had an opening in the buttery room that monks used in the old days.
I thought it was interesting and if you ever searched it out the info may help.

Little update here. Although it's still a work in progress, we have had a ton of use out of the cellar. Way more than I expected when we began the project. We have downsized to a small refrigerator in our tiny home, and are using this for all of our middle to long-term cold storage needs. After I rebuilt the partition wall, the upper interior stays at around 50, while the lower interior hovers around 35. Granted those temps vary a little according to temperature stratification, and how high on the shelves things are stored. Partition wall built with site-harvested wood scraps, remnants of greenhouse insulated plastic and upcycled vinyl cooler strips. All in all, I am so impressed and thrilled!  We have yet to  have the occasion to use it as a storm shelter, but with a little cot and some board games down there, I think it should be fun for the whole family.

This year, I would like to replace the corrugated plastic roofing with decking and an earthen roof.  I am weighing various possibilities for the methodology.  I am thinking I will use reclaimed barn siding for the decking and billboard tarp for the membrane, build a hardy eastern red cedar fascia/soil retainer, and layer old burlap and soil on the roof to stabilize the earth while rooting occurs.  Anyone have any suggestions for how best to keep the dirt on the roof during rooting?  I remember seeing Paul post a cool video about how, when building crazy engineered bridges and retaining walls for highway infrastructure, they help back-filled earth achieve repose by layering sheeting every few inches or feet.  But now I can't find it.  

Edit: I found it!  Here.

Airflow in a root cellar is important. Replacement air will come from underneath the door or next to it and exhaust air will go out from the upper portion of the back wall of a root cellar. It is possible that the opening at the end of your root cellar was used for dropping in ice or it was used as a coal chute.

Will you be lime washing your root cellar walls to prevent mold and mildew? How will you be disinfecting it annually?

Here's a simple recipe for lime washing the walls that I have from living in Finland where root cellars are still quite common:

5 kg slaked lime, (calcium hydroxide, Ca(OH)2.)
10l (equals 10kg) water

(in other words ratio of 1 part lime to 2 parts water in weight)

1. Mix lime to a small amount of water, until it resembles soupy porridge. Then add the rest of the water mixing it constantly.
2. Let it sit for 12 hrs.
3. Slowly mix it again and add more water if needed. It should look like milk, the consistency is also the same as milk. Lime wash paint is now ready to use.

Clean the walls with a brush or vacuum. If walls are made of concrete then mist them prior to paint application. When applying to the walls it will run like water, and it will look wet, which is part of the deal. It will eventually dry and turn white. Make sure to use a wide brush and criss cross overlapping each stroke as you paint or alternatively rub it in the nooks and crannies with a round brush.

As for maintenance. If you ever see brown spots, it is not mold, it just means that water has seeped through the paint. The spots will need to be brushed and washed off prior to adding lime wash and then once it is clean you can reapply the lime. Cement walls need to be treated more often than stone walls with the lime wash. Wear gloves and goggles when you apply the finish. Avoid wearing your Sunday pants, because the lime wash splatters everywhere.

Hi Heidi,

Welcome to Permies!

Heidi, thank you!  your first-hand experience is very much appreciated.

A thorough cleaning and lime-washing is on the calendar for this spring, and your input gives me a much better idea of what this entails for ongoing maintenance.

I have wondered if enough air exchange is happening through the door.  I am considering adding a buried pipe at floor level to draw in cooler air during the hottest summer months.

Thank you John!

Hi Beau! I don't have a root cellar yet in my yard, as I'm still working on other projects, but my relatives and friends do, which is where I'm learning from hands on and there are also research papers available in Finnish to draw knowledge from if you need translating. I find your project very interesting and educational. Please keep us posted on your progress.

I know the humidity in a cellar can be very local and seasonal. Only observation will tell you what it is in each individual cellar. There used to be a consensus of letting the cellar air out during Spring and Summer, but that can lead to condensation inside the cellar as warm humid air touches the cool surfaces of the cellar, so the experts are now saying to keep the door closed as mold issues tend to come from too much moisture. How are you keeping the ground level moisture under control? You mentioned an additional air intake pipe being installed possibly. Will you be adding a drain at the same time?

I am planning on adding a cold storage room or "wine cellar" in my basement as my first food storage after working on my pantry. I will be insulating it from the heated part of the house and keeping the exterior wall as exposed cinder block, the floor is concrete. I will also be adding a low air intake and high exhaust to the room. The intake I'm planning on doing as an earth tube that drains any condensations in the pipe outwards of the house. I will also be learning as I go as to what the humidity levels are near the floor compared to the ceiling. Such a fun project be working on!

Heidi Peters wrote:How are you keeping the ground level moisture under control? You mentioned an additional air intake pipe being installed possibly. Will you be adding a drain at the same time?

i had not considered a drain - in the 2 years I've had the cellar in use, I have not encountered any accumulated moisture on any surface, the exception  being a heavy rainfall event, where some ground moisture does seep through a couple of hairline cracks in the walls.  I'm moving some earth around to try to provide downhill paths for all rainwater away from the structure.  But, even when water entered the cellar, it didn't pool.  Just seemingly soaked up quickly into the massive monolithic concrete floor.  

I have not been measuring moisture, but I have been observing.  It seems like all my jars, roots, crates, and bins do just fine.  Fabrics, both organic and synthetic (like totes or bags, or my old winter coat) develop some growth over the course of about 12-months - not black mold, but just splotches of off-white/greenish.  So I'm eliminating those.  Cardboard seems to be an edge case.  I will start measuring humidity and taking notes.  

I hypothesize that adding a cool air intake and improving the seal at the door will improve thermal stability and increase good airflow.  

Heidi Peters wrote:I am planning on adding a cold storage room or "wine cellar" in my basement as my first food storage after working on my pantry. I will be insulating it from the heated part of the house and keeping the exterior wall as exposed cinder block, the floor is concrete. I will also be adding a low air intake and high exhaust to the room. The intake I'm planning on doing as an earth tube that drains any condensations in the pipe outwards of the house. I will also be learning as I go as to what the humidity levels are near the floor compared to the ceiling. Such a fun project be working on!

Sounds like a great project!  I would like to learn from you as you go.  There is also a "root cellar" in the basement of the 1907 farmhouse on our farm - but it is a stagnant and damp place.  My folks live in the house, and they are apparently fine, but I get sick from mold exposure if I ever spend too much time over there.  I am curious what is going wrong, and will plan to remediate the problem as I am able.  I'm wondering if there was originally some air intake that has become blocked over time.  I'll probably need a hazmat suit and respirator to perform a thorough inspection.

My grandma had a house that had a cold cellar that was excavated into granite base rock that the house was built on in the 1970s. It had an air intake on the bottom part of the door and also on the exterior wall near the ceiling. No insulation on the walls as the cellar was part of their basement that was only used for storing garden tools, bicycles and similar items. I suppose the granite kept the temperature very consistent all year round. She stored her preserves there and some root vegetables. She plugged the upper air exhaust with a rag when winters got too cold. I have issues with mold spores like yourself, but didn't have issues with that cellar. It was a really simple design and is still in use by the new owners.

Thanks Heidi, it's good to know it can be done.  One day I will have to get the farmhouse cellar sorted out.  For now though, one cellar at a time!

I was talking to my mom about the root cellar sometime last month, and she was describing her memories of waiting out tornadoes down there when she was a little girl in the late 50's.  They had a bench of sorts in the corner, and stashed a few board games and oil lamps to pass the time.  She doesn't remember much about the function or maintenance of the cellar, aside from that. They used to call it "the cave."

Beau,

May I ask where you live?  I am studying an old root cellar in Arkansas that looks like yours before your renovation of it. Trying to determine its age.

Gabby Jones wrote:Beau,

May I ask where you live?  I am studying an old root cellar in Arkansas that looks like yours before your renovation of it. Trying to determine its age.

I'm in South Central Kansas.

Have you asked in old-timers in the community?  Often times, a number of homesteads were building similar things around the same time, sharing materials, equipment, and labor, and someone might remember something from their childhood, or stories they've been told.