Root Cellar Construction, by George T.

To begin with my first root cellar (RC) was built in 1998, in anticipation of Y2K. I used a John Deere front loader to dig/excavate the area for a root cellar. I had worked as a Temp for a local business and they were retrofitting a former work area. They were disposing of some nice wood beams (4 x 12 x 20 fir) and they were going to haul them off to the dump. I offered to take them for free. So I was able to take about 16 – 18 of them, 1” plywood flooring and was able also to get two sets of stairs made out of 4 x 12 fir one was 8’ long and the other 4 foot long. I used the 8” for this RC and saved the other for posterity; with this I had my ceiling joists, stairs, ceiling tiles (ceiling insulation) and roofing/ceiling material. I ran 120 volts to the RC. I used pine logs for the vertical supports. I covered it with 30” of dirt. In the end I had built a 16′ x 20′ RC and had four lights inside.

The problems I later encountered, were:

  1. The walls were not thick enough and reinforced enough. I had used 7/16” OSB sheathing on the walls, and metal wall studs for horizontal support but they were few and far between. A few years later the walls started cracking and breaking inward from the pressure of earth and from freezing winters.
  2. The first two years I had considerable amount of moisture to contend with. I had metal cans of food rusting and other steel items that rusted as well and mold started to form on the wood posts and wooden walls.
  3. Dirt floor
  4. Not enough lights or power outlets
  5. Ceiling wasn’t high enough

After about 10 years of thinking and pondering my mistakes of the first RC and wanting to build another one. I set out on paper to rethink and to design a RC. It wasn’t until 2009 that I a real plan.

My New Plan

I decided that I wanted a hidden room within the cellar, 8 foot high ceiling, 110 electricity, phone, water, drain, 4” venting for a composting toilet, 4” intake and exhaust venting with blast gates with 2- 12 volt marine blower/exhaust fans (gel type batteries no gases emitted), escape hatch, wood floors, 110 volt lights & outlets, 12 volt lights, & two 2” pipe penetrations, one for water in/out (future for an outside water storage tank). The other for wiring i.e.: outside generator, and solar/wind power.

I began in 2010 using a borrowed John Deere tractor with a front loader to dig/excavate the area for a root cellar. After going as far as I could with it I stopped work of the area as time and money wasn’t available to me at the time. And frustrated that the area that I had worked on wasn’t deep enough and level enough for what I wanted to do.

The following year 2011, everything fell into place, the time, money and resources. I feel that I was lead to do this. I thank everyone in the spirit world who helped out and thanks to God, without theirs and God’s guidance this wouldn’t have been possible and to my loving wife who supported me in my efforts.

So excavating began:  I had dug out 2010 a spot 21’ x 20’.

I thought long and hard as to how to construct and what to construct the RC out of. I wanted it to be strong and yet inexpensive. I was led to using metal pallet racks. I researched the Internet for pallet racks most were fairly expensive even used. I went to the local steel salvage yard and was able to get qty. 43 – 44” x 19’ long pallet racks and paid about $1,450. Some were straight and some were crooked. Out of the 43 racks I used 41 of them. With a 16’ car hauler trailer I made two trips in taking them all home.

After acquiring the pallet racks, I was finally able to figure out how big to make the RC. I wanted to build approximately a 20’ x 20’ RC. I had a length of 19’ on the racks so with them being 44” wide, I ended up building a 19’ x 23’ RC with 97 1/2” walls with a 6’ x 8’ outside entry way, one door into the entry, one door to go into the outside room and another door to the hidden area. I cut some of the 19’ racks to 97 ½” long, giving me 27 vertical wall sections; 22 for the outside walls and 5 for the small cellar room. I reinforced each wall section with additional steel that I had or used from the racks themselves. Each wall section ended up weighing about 155 lbs. or more.

With the size of RC in mind, I rented a small crawler excavator. With it I was able to get deeper and bigger but placement of the excavated dirt was a problem, I was only able to get 4-5 feet deep into the earth. I also used it to dig a trench for a 1” water line and 1-1/2 “ PVC conduit for power/phone to the RC, after using the excavator for two days. I returned it and ended up hand shoveling the earth to level out the RC area.

I designed the RC to have two rooms: an entry room (approx. 8’ x 8’) for the entry hiding the main entrance door. And the rest was the main room to be separated by the entrance (hidden) door. I had a steel escape ladder that I had bought several years before, I installed that and installed an escape hatch.

I hand-dug the perimeter for footings and footings for the small RC area, framed it in with old lumber and used #4 rebar, 4 per footing the entire length of each footing. I used in all 66 bags of sacked concrete that each weighed 60 lbs. Why 60 lb. bags and not 80 lb. bags? 80 lbs. is more than I can handle at one time. I had a cheap Chinese electric concrete mixer that I used, it could handle up to 4 bags of concrete but I usually mixed 3 bags at a time. When I poured the concrete I embedded steel angle iron into the wet concrete so that I could later weld the steel frames (racks) to the angle iron keep them in place.

Forms & Rebar

To get the concrete into the area I used my fork truck and an extendable boom lift that I had made the year before. Because of the length of the boom and the weight of the concrete I could only move 6 bags at a time. The weight plus the length of the boom would lift up the back end of the fork truck if I exceeded the weight limit.

In the shop, welding the wall panels together I spent several days and pounds or welding wire (2 spools) welding the sections together. I cut some of the 19 foot pallet racks to 97 1/2“in length. Then I added 6 horizontal supports every 16” for support for the wood (7/8” thick for the outside walls). In all, there 22 vertical outside supports (for the perimeter of the RC and 5 inner vertical support walls the entry that were welded up and installed. I ended up welding flat bars across the facing of the joining vertical walls so that they would not bow inwardly from the outward pressures.

I built the new RC in the late summer and fire was a hazard with the welding that I was doing. I ended up sprinkling/watering the surrounding areas quite heavily so that no fires were started from the welding. I used a Hobart gas driven portable welder, In the RC area I ended up putting 14 hours on the welder in welding the pallet racks and wall sections together.

After the sections were fabricated, on the far Northwestern corner for the RC, a hole was dug about 3-1/2 feet deep for a 2” drain and a pipe was run from the Southwestern end of the NW hole. With the depth of the RC and with the hole that was dug the drain hole was about7-8 deep. Then 10 mil plastic sheeting was laid down over the concrete footings and piping. The sheeting was cut whereever each of the steel angle iron was imbedded into the concrete, to ease the location of them when I was ready to weld the “flooring “ pallet racks into place. With the fork truck I then lowered the 6-19’ steel frames of the flooring support into place.

After the pallet racks were laid in place; then they were welded to the footings (embedded angle iron and to themselves). One of the problems of welding with plastic in place is that the sparks and slag would burn holes into the plastic and sometimes the plastic itself would catch on fire. Though there weren’t that many holes, later in the construction before the wooden 1 1/8” T&G plywood flooring was laid another layer of 6 mil plastic sheeting was put down ensuring a proper vapor barrier.

After the base was set into place the wall sections were set on the base. Two sheets of 7/16” sheathing were placed onto the outside of the wall sections, giving a wall thickness of 7/8” thick. I coated each sheet in RV antifreeze and Borax mixture (one for bug deterrent and the other for weather preservation) and a cover of heavy visqueen. Looking back it would have been cheaper to have used ¾” flooring but it would have been 1/8” less in thickness. I tried using liquid nails to adhere the wood to the metal, the test piece that I had in the shop worked, but later keeping the wood adhered the metal frames. Later, self-drilling/tapping screws were used and that kept the wood adhered to the steel frames.

After the walls were in place I set in the overhead frames, to get away from posts in the RC area I used I-beams to support some of the overhead frames. The entry way was built and the entry door installed and the main hidden entrance door was installed. So actually there are 3 doors that a person goes through in order to get into the main room.

I covered the roof area as I did the walls, but used foam panels on top of wood and used visqueen to cover the top and then soil, later I found using visqueen was an error and I went with a heavy pond liner material instead.

Using Kilz for a primer on the inside metals and painted everything white so it would be brighter and lighter. We have been using this RC for several years now. What I have written so far is pretty much the basis of what I built with a little help from the wife.

Humidity in the RC usually runs about 75%, temperatures range from about 45-70 degrees, there is a phone line in there, sink with water and a drain line, improvised toilet, wood stove, 120 volts & LED lights, and a secondary escaped route if needed. There is a small area for seating and eating, and if need be cots for sleeping. There are lots of lights and storage racks to place the items to be stored.

It a humble place but far far better than what was before. I wanted the outside to look old and unassuming, like an old mine shaft or well house.




17 Comments

  1. Wish you had some photos. Good description of your process but would have been much more interesting and coherent if you had shown what you did and the results of your efforts. Good job though.

  2. Excellent. I always wanted details on a root cellar. Our next step in our build phase. Also, great that you have an entry room [decoy] and then the real “room” behind some secret contraption.

    If you recall the man in Oregon who evaded authorities for so many years with an arrest warrant was found out by a nosy hunter when peering into his self built cave on public lands. Had he built a secret room behind the entry room, threw a bunch of empty canned foods and left so trash around looking like it was deserted, he might have been still at large.

    🙂

  3. I buried a 20 ft shipping container which has worked like a dream for 10 years. I coated the outside with the black mastic used to waterproof cement foundations and stuck 2 in thick panels of blueboard onto that. I double layered the top and then placed rebar and 8 inches of concrete over that. I had to shore up the roof until the concrete was hardened but removed them afterward. There are other things I did that make it work well. Summer temps are around 60 F and winter temps around 45 F, no moisture problems, no spiders, no mice, etc. I grew up with the old earth style cellars and did not want to even mess with that style.

    1. I have to agree about reinforcement! Reinforcing the sides and top of a shipping container is a must, or they will be pushed in. They are simply not built to take weight anywhere except the corners, as originally constructed.

  4. Great post George.
    I think every person prepping should experience building an underground hide-e-hole.. I also built one under my house complete with hidden room under the stairs. I built mine in concrete and rebar and concrete filled CMU’s smeared with Quickwall mix. Mine runs about 10 feet deep, with stairs. humidity sits around 50% I store all my preps including my guns in it. My 100 lb door is part of my floor and uses hydraulic lifts to open it. I don’t have water running to it, But I have power and phone.. It stays at 60 to 65 degrees year round. It’s about 180 sq ft of floor space with a 6′ 3″ inch foot reinforced Concrete ceiling … It took me 8 months to dig it by hand using 18, 5 gallon paint buckets and 5 milk crates for the rocks. and another 5 months to build it. I set up an electricians wire puller as a winch to haul them up and rollers to roll them out the dog door to my truck… I spread it all out in an empty field owned by the railroad.I did the whole thing in absolute secrecy. It definitely has a cool factor most would marvel at. I took pictures of the project..

  5. Everyone seems to forget one of the best ways to support outside forces is the simple arch. Although not the easiest to build the arch supports extreme loads and last for centuries. Think back to the Roman times and how many of their arch’s are still standing. Arch’s are nothing more than a Quonset hut style and can be built the same. Once you have your area cleared it can be made with heavy wire mesh. Rebar would be better but more expensive and harder to deal with, covered with concrete, once hardened covered from all sides carefully and evenly and you’re done. Drawback is you will have some unused space and cannot stack straight up a wall. But the positive of that is air circulation, keeping moisture at bay. Square is the modern norm and easiest to work with as well as maximization of space. But old technologies sometimes, and in some cases are the most beneficial. Something to consider.

  6. For those of you building within an existing structure, if you can run a connection from your RC to a sewer stack, you may cut down a ton on your humidity. If the sewer stack has been properly designed and plumbed, you shouldn’t have to worry about sewer gases making it past all the downline traps. George T – hope you’re being real careful with that stove. If you’re getting that much humidity, I’d expect that to be a “confined space”. Great project.

  7. George, God bless your patience and getting over the goal line. Sounds like a lot of work but you kept going. That’s what I love about these articles; folks like you don’t assert having all the answers, admit minor mistakes and keep iterating to make it work. Thank you for the article.

    Squirrel 44

  8. Back in the mid-90’s my parents built a “root cellar” into the side of the hill behind their house. My step dad wasn’t sure of the engineering of such a thing. I gave him a set of circa 1960’s fallout shelter plans. With that he was able to design the “root cellar”. 2 large I beams were used to support the 12″ plus cement roof. Mafia blocks were used to fashions an eterance. The thing is huge at 20’x40′. The walls were made of block with filled cores. Water and electric was installed as well. Pipes for a toilet were also included that were tied into our septic system. My parents stored lots of food and other Surival supplies.

    The downside of the project was that my parents used local contractors to do a lot of the work. I met someone a few months later in the nearby small town and they asked where I lived and I told them and they responded by saying “oh is that the house with the bomb shelter?”

    After several years mold is a problem because of lack of good air movement and I believe because they put a sump pump pit inside that always has water in it.

  9. Well written and very explainative. WOW did you ever put In. You put in alot of expense, inginuity, time and physical effort on that project.

    What kind of generator did you put ,in? What size? Is it quiet? Used for backup? Gas or solar
    Expensive?

    I applaud you for all of that hard work! Did you and Sally open a bottle of bubbly to celebrate?
    Hope you did

    Now you will be bombarded for more great ideas
    Proud of you!
    Sis

  10. Editors: please work with the author to get and post photos. This is a very important project for most of us and the photos will help us understand the instructions better.
    Thank you.

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