# Building a root cellar



## Bungiex88 (Jan 2, 2016)

Had a question about a root cellar. I live on a hill side and was going to build a root cellar into the side of it. Was going to pour a concrete floor and concrete block for walls but what do you do for a roof. It will be covered by dirt so how would I go about this.


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## RonM (Jan 6, 2008)

Lay RR ties across the top cover with plywood, then cover with soil. Use old ties that are about bleached out.....


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## jwal10 (Jun 5, 2010)

Build a form with heavy lumber and plywood and shore up good. Use a form board (tray) around the top to pour concrete in. Put rebar in to reinforce the concrete roof slab. The concrete slab needs to just sit on top of the concrete block wall and be all 1 piece. Fill some of the voids in the concrete blocks and put some pieces of rebar in the concrete to anchor roof to walls. Remove form and shoring when concrete is cured and waterproof roof same as any walls covered with earth. Thickness of concrete roof depends on in size. Also spray formslip on forms and plywood before pouring concrete so it does not stick.


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## Bearfootfarm (Jul 13, 2006)

I agree with using concrete.
Nothing else will hold up to the soil moisture.

You can use corrugated metal roofing covered in a few layers of heavy plastic for the bottom of the form. Once the pour is cured, It would be a good idea to seal it with a good masonry waterproofing compound and covering with more plastic before completing the backfill with dirt.


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## TnAndy (Sep 15, 2005)

Skip the concrete floor, and use it on the roof as said above. Use pea gravel on the floor, you actually want a fair amount of humidity in a true root cellar, and this will help with that.

Photos of my roof under construction. Wood beam is temporary support.




















Tar paper over 2x wood, then rebar in place. Note the concrete will flow down in the holes in the top of the block wall to lock it all together. 6" finish thickness.











Pour day. Had it pumped while having another project pumped at the same time. 











After curing couple weeks, pulled the forms off and from under, covered the top with a piece of commercial roofing EDM rubber, tucking it up under the siding on the gable end of the garage to get a good water proof seal there, then backfilled with dozer.

Finished inside by removing tar paper (which wrinkled all to pieces, wouldn't bother using it again frankly), and couple coats of paint. Built insulated door out of 1x cedar, foam board, plywood on back side. Ran a few lights. Don't forget to leave some holes you can run ventilation piping.




















The vent on the right slopes down and away to the outside, has a small 'duct booster' fan in it on a timer so it draws in colder night air in the fall to cool the cellar faster.
Pipe on the left goes out, turns a 90 up, then has two 90's to make a rain proof vent. Both have screen wire siliconed in place to keep out critters.


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## Fishindude (May 19, 2015)

Very nice root cellar TnAndy !
That's pretty close to how I would build it too.


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## Jlynnp (Sep 9, 2014)

Andy I could sure use you to build one here!! That looks great.


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## melli (May 7, 2016)

Very nice TNAndy! Should be a 'root cellar' sticky...


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## fishhead (Jul 19, 2006)

Nice work on the cellar.

I have a question. Would you want the concrete to fill the entire block wall? 

I remember watching block layers tap the dividers in the special top row of blocks and lay them on their sides to mostly block the holes into the wall. That allowed the concrete to make a solid ring around the top course.


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## TnAndy (Sep 15, 2005)

I wanted it to fill the wall, or as much as it would fill. When you get concrete pumped, the aggregate is pretty small, so it flows pretty easy into block.


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## Bearfootfarm (Jul 13, 2006)

> I have a question. Would you want the concrete to fill the entire block wall?


It won't add any strength to the roof but it will make the walls a little stronger.

It just costs more to fill completely rather than just filling a couple of courses to tie it all together.

If you fill it entire wall it's best to use a vibrator to eliminate any voids.


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