Underground Root Cellar Construction

[OlJarhead]

Hi All,

One of my projects is to get a root cellar constructed at our property (along with the cabin I'm building that's posted elsewhere) and I've run into a bit of a bind -- mainly that I know nothing!

I followed the extras link to: http://www.forestryforum.com/members/donp/CalculatorIndex.htm

And used Southern Pine (and others) to see what Don P's calcs would tell me.  I set the total weight on the log at 2200lbs assuming 220lbs per square foot (2 feet of dirt covering roof of cellar) and the calculator appears to be telling me that a log spanning 10 feet and carrying 2200lbs would need to be about 7" in diameter at the center of the span if I'm reading this correctly.

I then upped the load to 4000lbs to see what change that would make as I am thinking I'll have more on the log if it is set on 16" centers (or more or less depending on what I learn) and it appears that #2 Southern Pine would need to be 7.5" in diameter mid span.

If I am reading this correctly then I should be able to frame the roof of the cellar with 8" diameter logs set 8-12" apart along the span of the roof.   Am I reading this right?

My plan for the roof is to set the logs on the walls (most likely bolted to the walls -- more on that later) and then nail 2x's or thick plywood to the logs and cover with 60 mil plastic draped down the length of the walls.

For walls I'm a little stumped.  Originally I was thinking I'd set the logs into the earth and bury them, but then I realized this might be a bad idea as the earth could cave so I set to searching for a wall design that could hold back the earth walls.  I originally though I'd build a 2x6 wall framed on 16" centers with PT plywood outer walls but then realized that might not nearly be strong enough so I began searching and couldn't find anything definitive (sure there are lots of blogs but nothing clearly stating what is safe).

So, do I build a log framed wall with a ply sheeting or an all log wall?  Is cinder blocks and concrete better for the walls? 

I also considered earth bags but then learned it might not be enough.

I'll post pics of the hole shortly but am hopeful some of you folks will jump in and help me out
Thanks!
Erik

[laffs]

ive never built one , ive seen a fe years ago made from granite, rocks, tohuge fuel tanks.

if your worried about the earth pushing in the walls, why not build a floor and put the walls on the ouside of the floor instead of on top
id consider rolled roofing or heavy tar paper on the roof maybe several layers, and then a liquid tar or driveway sealer on top of that

[Jasperfield]

You might consider a small shipping container. They are available as smal as 10' long and run on up to 40'.

Dig back in the bank, insert it, backfill the sides, and cover the roof.

You could cut holes in the bottom for moisture and heat; and do the same to run a vent out the top.

The walls and roof are strong enough to withstand large loads.

[OlJarhead]

Thanks guys.

At this point I've ruled out the shipping container (couldn't get one there if I wanted to) but it is an interesting idea.

I'm pretty sure log framed walls and roof is all that I need and I have a source for 60 mil plastic which is what the underground house guys use.  So, i just need to make sure I use big enough logs and determine the right way to construct the walls to hold back the dirt.

[SPIKER]

If possible I would go with cinder block walls & a poured floor.   since you are spanning this open room why not build a row of support shelves down the center to help support the roof?   there will be a need for shelves anyway to store food might as well make them heavy to help support the roof as well.

sealing up is important stop water getting in and coolness getting out.  venting is also needed to let the moisture out when it does gets in.

Mark

[OlJarhead]

If possible I would go with cinder block walls & a poured floor.   since you are spanning this open room why not build a row of support shelves down the center to help support the roof?   there will be a need for shelves anyway to store food might as well make them heavy to help support the roof as well.

sealing up is important stop water getting in and coolness getting out.  venting is also needed to let the moisture out when it does gets in.

Mark

I've been giving serious thought to cinder block walls reinforced with rebar and concrete and set on double width footings set 6" below the grade of the floor.  That would probably be more then strong enough, I just didn't want to do THAT much work in the start of this thing! haha

My original idea was a room made of strong wood walls and roof buried in the dirt like root cellars of old -- or so I thought.  However, it's looking like I need a lot more strength to hold the walls back and the 220psf load on the roof.

[Buck]

Invite the Magicman over. He knows about those blocks.

[thecfarm]

I have a root cellar under the sun room.A Lot differant than what you are doing.Mine is just a basement with no floor,just crushed stones.But do not pour a floor. You need the dirt to keep that room at a constant temp.

[chevytaHOE5674]

But do not pour a floor. You need the dirt to keep that room at a constant temp.

My root cellar has a poured cement floor, walls, and arched roof. It stays within a couple of degrees all year long. Been that way for about 80-90 years now.

[Sprucegum]

A row of 6x6 posts 3 or 4 feet apart. Nail 2x6or 8 planks on the outside and backfill; it will hold 

I would use 2x8 rough cut planks for ceiling joists and cover them with 2x whatever planks then plastic

Plywood is for city folks who don't have mills   

[OlJarhead]

A row of 6x6 posts 3 or 4 feet apart. Nail 2x6or 8 planks on the outside and backfill; it will hold 

I would use 2x8 rough cut planks for ceiling joists and cover them with 2x whatever planks then plastic

Plywood is for city folks who don't have mills   

Thanks!  So you think the 2x8 rough cuts will hold the load?  I've read that dirt is roughly 110lbs psf so the load on the beams will be 220lbs (2 feet of backfilled dirt to put the root cellar at optimum depth)?

6x6 posts should be easy enough to do and I was thinking of just milling it all anyway but I've got mostly pine so wanted to be sure before using it.

[Tom]

I'd build the roof out of the heaviest and best timbers I could find, if I were to use wood.  You are'nt figuring the load for just the dirt.  Who could guess what might traverse across the thing.  People will walk over it, lawn mowers maybe, tractors, trucks..? 

How many times have you heard of a truck falling into an old septic tank?

I'd build it like a fortress.

Are termites a problem?  They love Pine sapwood and will eat the heart from all but the very fat-lightered heart.

[Raider Bill]

You might consider a small shipping container. They are available as smal as 10' long and run on up to 40'.

Dig back in the bank, insert it, backfill the sides, and cover the roof.

You could cut holes in the bottom for moisture and heat; and do the same to run a vent out the top.

The walls and roof are strong enough to withstand large loads.

I know a guy that buried a 40' shipping container as described here. in 5 years it caved in due to moisture/rust from the dirt. He thought he had it figured out and coated the outsides with a high dollar membrane to no avail. This was done in SE Tenn and red clay soil.

[Sprucegum]

  I live in an area with no termites and no traffic so I never considered those problems 

The root cellars I have seen have been cut into a steep bank or tucked away behind the house where no one traveled except on foot, looking for a stray cow or goat 

The potato bins and shelves were all constructed of the same posts and planks and may well have given extra support to the roof. The soil was typically sand with some clay and the floor was left natural in most cases; especially in the bins.

[OlJarhead]

Thanks All,

Cows are a problem though I plan to fence that area which 'might' help with that.  Tractors shouldn't be an issue since I own the land and ought to know better (and intend to fence it which will keep ME from walking or driving over it).

However, I like the idea of a center support beam on heavy posts.  That ought to increase the load bearing capacity of the beams/logs used for the ceiling.

So, at this point I'm thinking 6x6x10 posts (PT's to be safe) buried 2' into the ground below the root cellar floor (if I can get down that far -- might have to settle for less -- with a 2x wall behind them painted with that green copper stain which is supposed to protect from termites and water damage (don't want to buy that many 2x PT's when I can mill my own right), then frame the roof with 8" partially sawn logs (flat top and bottom with round sides) spanning 10 feet but with a load bearing beam (8" log set on 6x6 posts on 5' centers -- maybe less) finished with 2x's painted with the a fore mentioned copper stain and covered in 60 mil (yes sixty mil) plastic.

I'll then be sure to keep lots of diatomaceus earth liberally spread in key places to keep the ants or termites at bay (which we seem to have plenty of in a pine forest).

I can keep the dirt floor (needed, I'm told, to ensure humidity remains high) and should have the strength to hold back the dirt (which is not moving now but the back fill has to put some pressure on the walls.

With an 8 foot ceiling I can put in a prehung steel door to give me some added security (deadbolts etc) and then make my own 2x outer door (there will be a 6x6 ante-chamber to enter before the main cellar to give a buffer zone).

Then I just have to work out the ascent to the ground above which I plan to make fairly steep with storm cellar type doors above (which will have 60 mil plastic inner coatings overlapping to keep water out.

With luck this will work and I'll get many years of use from it

I've heard wood framed cellars can last 15-20 years or longer.

[Jeff]

Root cellars used to be common where I grew up. We had one, and several of the neighbors had them. Every one but one that I was ever in were built of cement plastered concrete blocks with concrete floors and rebar reinforced ceilings. The one that wasn't, was built from wood by my great grandfather. By the time I came along, it was a hill with a hole in the top that everyone said to stay away from because it was a snake den. The concrete one that was on the property I grew up on was built by a previous landowner, probably in the 1920a dad thought. It's still there today.  It's probably on its 3rd set of wooden doors since I was born last I knew.

[Troublermaker]

I know what you talking about Jeff. A man that I use to work for dug a hole out in a hill side big enough for a 10X10 root cellar with 7 foot high walls. We form it up and pour a 4 inch concrete floor with a drain in the middle. Then he use  8 inch cinder block for the walls. We form up a roof out of plywood and cover it with old roofing tin and 2x4. It was brace every way that you think of cause he was going to pour a concrete roof. We nail up some 2x12 so that 4 inches was over the blocks. He went to the junk yard and got some 1 inch rebar that we laid across the roof every 2 feet both ways so that the rebar was sitting on the walls. I had some pieces of concrete that was 2 inches thick that we use to raise the rebar. Then we pour concrete in the wall blocks with 1/2 rebar and pour the roof. He raise the center 4 or 5 inches making like a low A roof. Then 2 or 3 coats of tar on the side and top all cover with plastic. He back fill it slowly and put 2 to 3 feet of dirt on top. I don't know what it would have cost to have some one to build it but I know that it would have been plenty. Except for the 1 inch rebar and concrete he had everything left over from difference jobs and my labor was free. It stays a constant 50 to 55 degrees year-round.

[red]

how many bedrooms will it have electric 

[OlJarhead]

how many bedrooms will it have electric 

Huh?  No bedrooms, it's a root cellar.

Electric provided via solar panel and 12v battery only.

[OlJarhead]

Interesting posts on the concrete structures.  Of course, to do that I'd have to somehow haul up a couple tons of bags of concrete and a mixer and do it all by hand -- not going to happen.

Not sure how the snakes got into the hole but I've read that wood root cellars don't last forever (in damp places anyway)...but I've also heard of some lasting more then two decades if cared for.

Will it last 100 years?  I highly doubt it but then if it last two decades I'm sure a time will come that I can use the trackhoe to clean it out and rebuild it with something longer lasting.  Today, however, it's wood me thinks.

[Jeff]

Twenty years does not sound like a long time unless you only have 10 years to live.  You figure if it only lasts twenty years, at some point in the latter part of its life you have to worry about it caving in.

[Jasperfield]

The thing to be aware of re the walls is hydrostatic pressure. If the dirt is backfilled directly onto the walls and later that same dirt becomes wet (which it will) or possibly even saturated, then the lateral load on the walls will become very high.

To avoid this condition, place stone about the size of d50 railroad ballast, or smaller, against the wall as you backfill. You'll only need a one or 1.5' width of this stone. This will prevent soil borne water from creating hydrostatic pressure against the walls.

[OlJarhead]

Twenty years does not sound like a long time unless you only have 10 years to live.  You figure if it only lasts twenty years, at some point in the latter part of its life you have to worry about it caving in.

With my injuries and exposure to nerve gas and excessive oil well smoke I hope I'm healthy enough in 20 years to be there and using the root cellar

Seriously though, you have to pick your battles and it is entirely possible that a well made wood root cellar will last three decades or possible even more.  After all, there are still mines with wood beams holding up sections that were places 100 years ago.  Not saying I'd want to go in there but I am saying that it is possible to have a root cellar made of wood last a LOT longer then you might think.

For one, remember I mentioned 60 mil plastic?  It isn't just a plastic bag I'm talking about here folks, but rather EDPM (http://en.wikipedia.org/wiki/EPDM_rubber) which is used by people who build underground houses with wood beams etc.

If you build it strong and coat it correctly then it is possible it will be around a long long time and if it is maintained properly with some care and repair it is possible it will out last this old jarhead

If not, I'll dig it out and concrete it in (in 20 years it's more likely that my sons will mind you).

That's my plan anyway

[red]

how about a vent

[Farmboy]

I was speaking with a friend of mine from Sweden.  He told me that all of theirs are built out of stone with mortar.  Not sure if your site would provide you with the materials for this, but it may be worth considering.  You likely wouldn't need to bring in too much mortar to complete your project.

[OlJarhead]

I was speaking with a friend of mine from Sweden.  He told me that all of theirs are built out of stone with mortar.  Not sure if your site would provide you with the materials for this, but it may be worth considering.  You likely wouldn't need to bring in too much mortar to complete your project.

I do have a lot of rock on the property (granite mostly I think)...but I know nothing of mortaring a wall together (though I wouldn't mind learning).

It is appealing to me anyway.

[OlJarhead]

http://floydcountyinview.com/rcconstruction.html
30+ years?  His root cellar is smaller then what I'm planning (and have dig already) but it encourages me to stick to my plans.

[OlJarhead]

Looking towards the root cellar.


Standing in and looking out of the hole.

[laffs]

 
the old ones i see in the woods where i hunt were made with stone. tapered from the bottom to the top. the taper, i was told served two purposes. 1. they could use the taper rocks as staging to pot up the higher rocks. 2.it kept the soil away from the inner wall.

you could mortar or plaster the inner wall. id pour the roof, build a form and use rebar. crushed stone or sand on the floor.

thats just the hippie in me talking , you do as you want

[krusty]

I ended up going with a concrete septic tank that was new but had a defect in it and would never be used for sewage purposes. After much dust and cursing I had a door cut in the wall and was the fastest way to get one that will last many lifetimes.

[OlJarhead]

I'm starting to shape up my plan with some modifications (thanks to a conversation with a fellow forum member a week ago or so).

My plan is to use RR Ties as posts and to frame between them with 2x6's, then cover the walls (exterior) with either milled and treated pine or PT ply -- still deciding there.  The top plate on the walls will be RR Ties also.  The ties will be sunk 12-18" down below grade and possibly concreted in place or set on ties (still thinking).

The roof will be framed with a center beam to added support and min 8" logs milled to 8" depth on two sides but left round on the others (basically a two sided cant).  Above those will be 2x's nailed to the log beams.

All of this will be covered in 60 mil plastic to drains around the outside before back-filling.  During back-filling we will try to ensure drain rock is placed between wall and dirt.

Two vents will be installed.  One vent will be installed near the ceiling while the other will be close to the floor.  Both will have screens and be fitted with 180 degree bends above ground to stop snow/rain from entering via the vents.  Each vent will have a wood 'flap' valve to allow them to be shut off in very high or very low temperatures.

The 'airlock' room will be slightly smaller but perhaps large enough to allow storage of things separate from the main cellar that don't need as well regulated temperatures and humidity.  I'm thinking 6 feet deep by 8 feet wide.

In front of the 'air lock' room I'm thinking of enclosing a 6'x6' space and running stairs out from it to ground level with typical sloped cellar doors above.

This will give me an outer set of doors I can lock, and two inner doors.

I expect with it being 10 feet down at the floor with 2 feet of ground cover the temperature should remain very constant year round

Wish me luck!

[routestep]

My brother just got a root cellar approved by the building inspector but he hasn't started digging yet.

10 by 12 by 8ft tall.

12 in block, groot down every other hole with #5 rebar

Curved ceiling poured concrete ( 7 inches thick at the centerline) with rebar both directions (#7 I think !)

Back fill with 3 feet of dirt overhead

Two 6 inch air vents through the ceiling.

I think he could use it as a bomb shelter the way it was engineered.

Not sure just when the digging starts, he spends half the day looking at weather radar on his new phone device.

[lynches lumber]

oljarhead_ any updates?

[fishpharmer]

Google "Mike Oehler"

[SwampDonkey]

Being as I'm in potato country, there were root cellars all through the country until all the new potato shed construction was becoming above ground in the 1980's. They were all cement walled and floors and it was very cool in the summer. But for bulk storage they needed to strap wood to the walls for air flow and it also kept potatoes from freezing near frost pockets where the walls where near the surface of the earthen banks. Like any living thing, root crops respire and that makes heat. Most sheds only needed a heat source near the doors of the buildings, usually wood and sometimes something like a salamander or what was called a silent glow stove that burned stove oil and sounded like a jet engine. I don't know where the silent came into it. My father used wood and then the stove was used when the doors where opened for loading trucks because often times the sheds where pretty stuffed with taters up to within 20 feet of the doors.


An old trick in the spring time, April in these parts, was to use the front end loader and scoop up some snow from a big old snow drift and place a pile of it at the entry of the sheds, but where the melt water has a place to drain away. I know one old farmer that still does this in his above ground sheds, as he grows seed potatoes and you can't put sprout inhibitor on seed. It's like a free air cooling system. In ice houses they used river ice and ice from the north country up here, and I assume Michigan to, was shipped by boats for far and wide. It was a big industry. Anyway, the ice was layered with sawdust and it kept pretty good until mid summer. These shacks were also in the side of a earthen bank. My grandfather hauled ice from the river until the 50's and for folks all over the area, as did others.

I've enjoyed reading your thread.

[Thehardway]

It sounds to me like there are several different ideas or theories as to what a root cellar is.  My grandparents had what they called a "root cellar" in their basement,  a home which my grandfather constructed in the 1950's.  It was no different than the rest of the basement other than they never poured the floor.  This was to provide humidity and cooling through evaporation.

Some of what is described here sounds like what we call ice houses.  All concrete or stone.  Ice blocks were cut from the river in winter and put in the ice house.  Sawdust was often put on the concrete floor to insulate the ice from the floor and make it last longer.

There is a root cellar at my current home. It was made of 8" block and has a gravel floor and a wood roof.  The roof is not covered with soil, instead a shed was built on top.  3 Sides are bermed. It has concrete shelves for vegetable storage 

I would not use edpm in a root cellar as it needs to breathe well. The evaporation of moisture from the earth, condensation evaporation from the masonry walls etc. provides extra cooling and keeps the humidity levels up. If the space is too tight and does not breathe well your food will rot.

I would make a vote for a slip formed stone/mortar structure.  Slip forming is not difficult.  Make a 2 sided box the width you desire the thickness of you walls to be. and about 2' high  I would go with about 18" wide. You then you place mortar in it, set stones in the mortar fitting the stone together in the bottom as close as possible like a puzzle, more mortar, more stone, more or less fitting the stone in the mortar as close as possible and using the form as your vertical guide to contain the stone and mortar. after you have the 2 ' filled in, you let it set up overnight and the following day you raise the forms and go up another 2' in the same manner until you have acheived the height desired.  This is pretty basic and provided you keep your mortar mixed properly and your stones fairly clean it will provide a very durable wall.  Use a tamped earthen floor and  this would make a very traditional root cellar.

Another method is called ferrocement.  You form the stucture in an arch with light wood. Over this you place chicken wire.  Cover the chicken wire with a layer of cement troweled on. Put more chicken wire over this while wet so it embeds. allow it to dry, repeat until you have several thicknesses built up to the desired strength.  once it has hardened thoroughly (20 days) you can remove the light wood frame. The inside is then plastered with a lime based mortar and you are all set.  Ferro cement arches are extremely strong.  they do not have to be as thick as what you might think. The strength is in the shape, uniform loading, and the way cement and steel bond together.  They actually made concrete ships in this manner.  They were thin enough to be light in the water but strong enough to hold a considerable payload and the pressure of the water.


Just a thought.  Good luck with your project.

[OlJarhead]

oljarhead_ any updates?

Sorry no.

I've been working on various other projects (interior paneling, floors, kitchen, pump etc) and haven't had a chance to get back to the root cellar.  I plan to do the root cellar in the spring but for now it's just a big hole

[den]

You could down size this

http://www.ag.ndsu.edu/aben-plans/5491.pdf

http://www.ag.ndsu.edu/extension-aben/buildingplans

http://www.public.iastate.edu/~mwps_dis/mwps_web/frame_p.htm

[den]

Or this

http://www.ag.ndsu.edu/aben-plans/5748.pdf

[OlJarhead]

Interesting stuff.  Thanks guys.

I'm torn between Railroad Tie posts and log beams (or tie beams) and concrete as well as 2x framing but still unsure which way I'm going to go.

Been working on the cabin too much lately to get back to this...the hole is dug though

[edkemper]

Jarhead,

I've come late to this conversation but may have something to add.

Rebar.

Log walls with log roof sitting on top of the walls. Rebar pin the roof logs to the wall logs. You can drill the logs, but make the holes 1/8th" smaller than the rebar. Then put a few layers of plastic on top. Ain't going anywhere.

[OlJarhead]

Jarhead,

I've come late to this conversation but may have something to add.

Rebar.

Log walls with log roof sitting on top of the walls. Rebar pin the roof logs to the wall logs. You can drill the logs, but make the holes 1/8th" smaller than the rebar. Then put a few layers of plastic on top. Ain't going anywhere.

Thanks!  I'm seriously thinking of using RR Ties to frame the walls and then logs on top.  Was thinking of 12" galvy spikes to hold it together but Rebar would work too.

This spring will be the time when I have to settle and make it happen

[Bandmill Bandit]

Hey Jarhead

i think we may have talked on the phone about this but may have been some one else that was doing the same thing.

We built one into a hill side for my dad about 25 years ago.

We used 12 inches of 2 inch washed drain rock as a base with good pine 3 by 12 "bull pen rails" as footing. we sprayed those with a wood preservative 5 or 6 coats and then used 2x8 PT pine on 12 inch centers with 3/4 inch PT plywood outside sheeting that ran down to the bottom of the 3"x12". we insulated to 6 foot below grade and lined with 3/8 spruce plywood. bottom 18 inches is not insulated or lined. We used 3/8 rebar as big nails for joinery at base and roof line. Cut to needed length and the pre drilled the holes to put them in place.

3 rooms, front room is air lock and storage for containers used in the cellar and measures 4'X16' the 2 back rooms measure 8' by 8' (outside). One side is used for root veggies and such while the other side is used for canned preserves, ciders/juices, and wines. Roof is railroad ties set on edge with PT 1/2 inch ply wood on top and inside ceiling 3 sides and top of structure were  wrapped in black plastic and then backfilled with a top side over burden that is settled to about 2.5 feet now. Vents are 4 and 6 inch PVC pipe with adjustable vent doors.

Railroad tie retaining walls V'ed back at 45 degree angles to give a good working area out side the entry door with a good 12 inch deep 3/4 inch road crush apron to park/work on.   



 

[OlJarhead]

Hey Jarhead

i think we may have talked on the phone about this but may have been some one else that was doing the same thing.

We built one into a hill side for my dad about 25 years ago.

We used 12 inches of 2 inch washed drain rock as a base with good pine 3 by 12 "bull pen rails" as footing. we sprayed those with a wood preservative 5 or 6 coats and then used 2x8 PT pine on 12 inch centers with 3/4 inch PT plywood outside sheeting that ran down to the bottom of the 3"x12". we insulated to 6 foot below grade and lined with 3/8 spruce plywood. bottom 18 inches is not insulated or lined. We used 3/8 rebar as big nails for joinery at base and roof line. Cut to needed length and the pre drilled the holes to put them in place.

3 rooms, front room is air lock and storage for containers used in the cellar and measures 4'X16' the 2 back rooms measure 8' by 8' (outside). One side is used for root veggies and such while the other side is used for canned preserves, ciders/juices, and wines. Roof is railroad ties set on edge with PT 1/2 inch ply wood on top and inside ceiling 3 sides and top of structure were  wrapped in black plastic and then backfilled with a top side over burden that is settled to about 2.5 feet now. Vents are 4 and 6 inch PVC pipe with adjustable vent doors.

Railroad tie retaining walls V'ed back at 45 degree angles to give a good working area out side the entry door with a good 12 inch deep 3/4 inch road crush apron to park/work on.   

We did!  And thanks   You were the one that convinced me that I was on the right track but I got busy with other parts of the project.  Most likely I'm going to build a variation of your root cellar though with this post I see a couple things I missed on the phone with you.

Thanks again because it's likely mine will be very similar!

[OlJarhead]

The saga continues.

A recent discussion with a neighbor made me think that a combination of the ideas presented here and elsewhere might work very well:

Cinder block and concrete walls, heavy timber roof construction covered in 60 mil plastic.

Due to the location there is NO WAY a concrete truck can get in and carting tons of concrete bags is also out of the question (my 1/2 ton truck could perhaps handle a fair amount in one trip on a smooth hiway but my driveway with it's 16% grades etc isn't likely to make it as easy as that!

A neighbor has a mixer though, and with some serious effort and lots of bags of concrete we could pour a foundation, stick rebar in it (to fix the blocks in place) and then begin stacking blocks on top of the foundation (once it sets) and then fill them afterwards with concrete.

This reduces the overall concrete needed to make the walls yet still makes a pretty solid and strong wall to support the heavy roof.

Then we put 10" logs on top of the walls every 2' or less (maybe every 12" but I think that might be overkill (still looking for load bearing info) and drop a 2x6 lid on top of that from my mill.  Finally after putting in vents and doing a little concrete work around the log ends to keep them in place (also use rebar for that through the log and into the concrete walls) we can cover with 60 mil plastic to ensure it stays dry.

I'll put in drain rock on the outside of the footings and french cesspits for added drainage to help keep the water out.

The 'airlock' or 'dry' room will get a concrete floor also while the root cellar remains a dirt floor.

Then when all is done I'll build a cinderblock stairwell to the surface and build a 'garden shed' right on top of the stairwell to provide cover for it so it doesn't build up snow and rainwater and adds a little security.

Thoughts?
Thanks
Erik
 

[jueston]

sounds like a well thought out plan, and like one that balances the difficulty of getting materials in with the need for strength.

i really like the idea of the garden shed over the access door, makes it all seem very secretive....

[OlJarhead]

Out of sight, out of mind

But it also helps keep it cooler in the summer by insulating it a bit more from the summer heat as well as solving the problem of keeping out the winter snow or spring rain.

Also solved the the problem if how to get enough headroom in the stairwell down to the 1st room (Dry room).

Once the orchard is in and producing (4 to 5 years after putting the trees in) it will provide a good place to store excess fruit and if we ever start farming then a place to store root crops as well as dry goods (wheat etc) that we might want to store for long periods.

For me, a farm without a root cellar is like, well, not a very good farm!

[ljmathias]

Wow, talk about overbuilt!  Tell us the truth, now: this is really a bomb shelter/safe room in case of some natural or man-made disaster.   

Your plan will work fine but I don't envy your back pains- lifting concrete up to pour in the blocks will be a killer or do you have a FEL to help with that?  Way I addressed this when forming up the blocks for the raised slab I built was to use the bucket of the FEL as my mixing trough: pour in 2-3 bags of sackcrete, add water, mix with a hoe, and then carry it to the wall where I could easily shovel it in and pack it down.  Don't skip the packing down part- big air bubbles can form.

Are you going to put membrane seal on the outside of the block walls to keep moisture out?  Since you're going to all this trouble, why not go that extra step and make it dry as well as secure?  I understand the new sealants are pretty good...

Lj

[OlJarhead]

Overbuilt?

I really have no idea what I'm doing which is why the posts of course.

I planned on building the whole thing out of wood but started to shy away from doing so for various reasons and because of the location I can't just have someone pour it with a concrete truck and pumper truck so this was an attempt at a compromise.

And no, not a bomb shelter etc, just a root cellar.

I'm putting in a small orchard but hope some day to farm the land and so the root cellar would be vital for an off-grid farm.

[beenthere]

As you are off in the forest, it should be a good safe place for protection from a forest fire.

[jueston]

we will know for sure when we see the door. if its 6 inches thick its a bomb shelter.... the pictures when its finished will give us the answers we are looking for...

[OlJarhead]

As you are off in the forest, it should be a good safe place for protection from a forest fire.

Might be, as long as you keep trees away so the fire doesn't suck the Oxygen out!  But it should also be a secure place to store things you don't want unwanted guests to get at.

[OlJarhead]

no 6" doors!  Though...now that you mention it....

Nah haha just a good steel exterior door with an extra lock or two.

Of course if the garden shed is well constructed and stocked one might not even know there is a cellar under it

[SwampDonkey]

just a good steel exterior door with an extra lock or two.

Are the bears that troublesome out there?

[OlJarhead]

Actually bears could be a problem though the closest I've seen tracks is about 1000 feet from the cabin up on top of the hill.

Meth heads are more likely an issue but up there it's a little less likely then closer to town.

However, I've been told that if it isn't tied down it's likely to eventually take a walk so tie it all down and lock it all up.

[OlJarhead]

http://www.drystacked.com/sequence.html thanks to another forum I did a search and found this.

I beleive using this method of building the walls I can get it done much faster then a traditional mortar job.

My biggest challenge now is both to cut and mill the logs without ridding myself of all good logs and of course, getting someone with knowledge to come out and help with the foundation pour.  I've done some concrete work but want the floor in the dry room to be well done and everything else done right too so figure I'll have to con a work buddy into the long treck up to the cabin as he has all the tools and the knowledge

[SwampDonkey]

I thought you were more remote. I could go to areas around here and never hardly see a soul all winter, probably no one at all. In fact, I could go to the woodlot this time of year, which is 3 miles away and I know no one will be there this winter.

[OlJarhead]

Nearest town is ~23 miles away and has only about 900 people in it.  Another is about the same distance if you travel 4x4 roads and forest roads to get there (so takes longer) and has about 1200 people.

Have a neighbor about 1/2 mile away through the forest (rumor has it one of the kids living there -- kids being in their 20's or 30's -- is wanted by the law in Michigan) or about 1/2 to 2 miles by road and another neighbor about 3/4's of a mile away (more buy road).

Nearest store is about 3-4 miles and it's all by it's lonesome (as in no other stores etc for 20+ miles).

So we're fairly remote but I've learned that no matter how remote and hidden you are you could still be found and left with nothing by those who like to do that sort of thing.

[Bandmill Bandit]

Looks to me like you have it pretty much built in your head and I think it sounds about right. Over built is better then poorly built. One other thing for materials to use if available is Tamarack logs and lumber. Need to get that stuff in place ASAP after it comes of the stump but it will out last any thing treated that I have ever  seen.

I swear the stuff grows petrified.

[OlJarhead]

Looks to me like you have it pretty much built in your head and I think it sounds about right. Over built is better then poorly built. One other thing for materials to use if available is Tamarack logs and lumber. Need to get that stuff in place ASAP after it comes of the stump but it will out last any thing treated that I have ever  seen.

I swear the stuff grows petrified.

Hmmm, I have some Tamarack though I planned to let it grow to eventually cut and burn in the woodstove...most of my trees are under 10" in diameter though I think, whereas I have a lot of pine that's big enough and perhaps enough Fir....I'll check again though!

Thanks