Basement

I would like to build a 600 sq ft house into the side of a hill.  I would like it to have a full basement - or as nearly full as I can.  The basement will be used for storage - especially for storage of root crops, preserved foods, etc.  I would like to have 3-5' of soil between the basement and the house on top of it, for the sake of having the basement being lower (and cooler).    I was thinking of using earth bags but was not sure about the need for some kind of pillars in the wall to support the weight of the beams in the ceiling - as well as the 5' of soil on top.  Any suggestions?

Additionally...the house will be a rectangle, divided into 3 approximately 200 sq. ft areas.  The basement will be divided into the same areas, so it is very natural to put the interior walls in the basement directly under the walls of the house.  I would like one of the interior walls of the house to be a rocket stove - maybe not the whole thing but a substantial portion - read: heavy.

Hi Tom, would the living floor of the house be sunk into the hill and the basement of the house be deeper underground?  Or is the basement a "walk out"?  

It sounds to me like having a basement with 4-5' of earth above it to keep the cold down is excessive.  Just surrounding the basement with cold soil on the bottom and sides plus the natural stratification of cold air seems to me like it would keep the basement cold.  I believe 1' of insulation in the floor would have more of an R value than 5' of dirt.  

Check out the My Little Homestead videos on their MusArt underground studio for some ideas:

The basement would be completely underground.  The "house" would have 3 sides underground but with one side open to the outside.  Think of a hobbit house.

In that case, adding feet of earth between basement and living floor would be massive overkill. If you don't insulate around or under the basement, it will keep the average annual soil temperature. I have a walk-out basement facing south with only one side fully buried, and it is cool all summer.

Ditto what Glenn said.  My house has a basement that is 1/2 exposed and an open staircase to the upstairs.  Even with that staircase it's consistently 15 degrees cooler downstairs in the summer.

He wants a root cellar basement. 15 degrees wouldn't even do it in a cool summer area like mine.

To get the results he wants means we need the space to remain under 60F at all times, closer to 50 would be better.

On that note, Tom, what area are you working with? That's relevant.

Yes, the climate zone is critical to this. Some say the earth is always 55 or 50 or 60 degrees F, but in reality, it approximates to the local average annual air temperature. In cold northern climates, a root cellar could be plenty cold, while in southern areas, it will never get cold no matter how you build it.

Glenn Herbert wrote:Yes, the climate zone is critical to this. Some say the earth is always 55 or 50 or 60 degrees F, but in reality, it approximates to the local average annual air temperature. In cold northern climates, a root cellar could be plenty cold, while in southern areas, it will never get cold no matter how you build it.

SE Oregon

Yup, as Glenn says, you'll be unlikely to get the basement any colder than the surrounding earth.  That surrounding earth should approximate your annual average temperature the deeper you go.  My wild guess is that your average will be warmer than a root cellar (33-40F).  

My root cellar in Northern Wisconsin gets down to those temps from late November until mid March.  It relies on being partially exposed on one side to the outside air to get that cold.  If it was deeper in the ground it may be harder to get that cold, even here in the frozen north.  

I also compensate by drawing in outside air on cold fall nights with a little fan.  

Tom, earthbags can support a great deal of weight and are commonly used as foundation elements for other forms of building. I suggest a solid reinforced concrete bond beam at the top of your basement and then again at the top of the upper portion. These bond beams will make good attachment points for the floor joists and the roof rafters.