Underground housing

My original plan is sited on a hilltop. However, there are several factors to that decision which made this the suitable solution for the situation.

1. There is a higher hill to the west (with a saddle in between) which acts as a diversion to prevailing wind (i've tested this) and provides an area of runoff for water and catchment for home water supply.

2. I live in an area of red clay hills. The soil around here swells a lot with moisture and heaves some in the winter. The soil is also very conductive, which is good for electric fence, but bad for anything plugged in with a solid ground during a lightning storm. The problem with all this, is that the ground moves. A lot. 3 to 6 inches a year of downhill creep is not that unheard of. The football field where I went to high school lost 54" of one end zone over about a 10 year period because the hill was sliding down onto the field.

Now as one can imagine, a hillside is NOT the place to build a structure. At least not one that will last. And consequently, the keypoint will move as well, in less than a generation.

Since the only really stable ground is on the hilltops (and even then I've come to think of a building as "floating" on the surface rather than anchored there) That's really the only reasonable place to put it.

3. In the winter time, especially in the spring breakup, the ground turns into a bottomless quagmire of clay and mud. My ancestors used this fact and built roads along ridge tops wherever possible, so that the roads would be dry and solid faster. In order to make a driveway to the keypoint on my property (which consequestly is under rushing water a couple times a year, would be a huge undertaking, and require lots of gravel and rock to build up a base that isn't just mud.


I think the house design is forgiving enough with concern to environmental variables that it won't be as affected by the things that Mollison notes are negative about the site. It's not perfect but I feel that it's the best solution for the situation that I have at hand. I wish I had a place where Mollison's principles would work, but I don't have a textbook property.

My thinking is that a hillside is the perfect place to build.  Why would you want to not build on a hillside? 

Of course, if you are building a box on the ground, well, then, yeah, a hillside seems like a bad idea.

But an Oehler structure:  a hillside seems perfect.

any of you seen the 50$ underground house videos?  I saw some posts on it but  figured i would say do in this posting. Personally i think the hillside is the best but if all you have is flat ground its got to do..  Its allot easier to deal with drainage on a hillside..  Beyond all the other smaller issues..

I own the videos and have seen them.

The videos do an excellent job of showing how to keep the roof design and to get sun coming in from all four directions.

Here is a video tour of Mike's $50 house and $500 house:

Hi all.

Sorry to be double posting, as I'm copy/pasting from the ridgetop house thread, but I thought it was appropriate here.

Obviously the loads that bermed/wofati/underground walls have to withstand, both vertical and horizontal, are very significant.
I'm currently of the opinion that  properly insulated earthbag laid in profoundly curved/circular shapes would be the best option for exterior walls rather than lumber.

The sand solution to the termite problem also seems appropriate as a protective layer for the "pond liner" type moisture barrier.

paul wheaton wrote:

PSP has no cement.  It is logs (from your property) + wood planks + black plastic.  Inside your home, it looks kinda like a wood cabin.   But the real magic is with the windows facing uphill.  It sounds wacky at first - but once you understand how it works, it seems (to me) to be damn smart.

Gee, you're right about it sounding wacky at first Paul.
Losing all of that low angle sunlight that is so important in winter..
Could you point us in the right direction to some info that will help us understand the concept?
Thanks

The wofati article is a good start.  Then there is mike's book.

Having thought about it,  a pole structure similar to the log built Holzer animal shelter in the slow-down-lardass article, using a profoundly curved/circular shape rather than square/rectangular for the exterior walls should be able to withstand the horizontal forces fairly well if thoroughly braced internally.

but I'm still struggling with the benefits of having 50% of the uphill wall being windows if cold is ever an issue.
They would never receive direct sunlight for thermal gain, and any warm air in the house would naturally rise towards the windows so they would only contribute to thermal loss. In winter (assuming downhill is sunward) the space directly in front of the uphill windows would also be in constant shade and further contribute to heat loss.

I don't want to be a party pooper on this aspect, but the drawbacks relative to the benefits seem fairly large. Obviously double and triple pane glass would alleviate the problem, but it's a huge expenditure to have a view of a wall in the shade. Would significantly reducing the uphill window area be a bad thing?

Please fill me in if I'm on the wrong track.
Thanks

You could reduce it if it is to your liking.  Mikes thing was that he thought anything above the soil should be glass for the most part.  It keeps you from feeling as if you are underground. 

We have 16 feet x 6'4 or so glass looking into the uphill patio.  We have a greenhouse over it so it is not as cold as outside but I don't keep it well sealed.  The earth keeps the cold away so well that heating is not a problem for us.  Months of 80 degree nights here do make me want to seal things up better and insulate the parts that poke out of the ground to the south and west. 

My wife wanted it more like Mikes ridge house for her views on those two sides.  We do get light from 4 sides as Mike felt it was important.

Styrofoam releases some off gasses and its not very green.

I also would avoid building on a promontory.  On a slope is better.  It also makes earthmoving easier.

Were I live there were thousands of Black Locust trees planted in the 1930s 

I wonder what the inside of a house made of black locust would smell like.  Good?

As for the glass letting the heat out:  it also lets more light in.  But here is another thought:  a lot of your walls can be adding heat in the winter and sucking heat out in the summer. 

I plan to use aged black locust for my next construction... I have never noticed any odd smell from green B. Locust - smells good to me.

Hard woods expand (circumference not length wise) when they dry. I am planning to use the cord wood construction for parts of the wall and B. Locust is my wood of choice.

ronie wrote:
Hard woods expand (circumference not length wise) when they dry.

Yowza!  That one is new to me.  In fact, it seems the opposite of what I always thought. 

In fact, I've found lots of folks against cordwood buildings because the wood shrinks and the wind just whistles on through.  But if it expands, then it seems that the wall would fall apart.

Expands isn't the right word. Hardwoods get slightly larger (circumference) when they dry. Now if you really want to be confused... they get larger by contracting!   As the wood contracts it splits causing a slightly larger circumference. SO if you have a piece of firewood say 3 inches in diameter and maybe 2 ft long... it is nice and tight until it dries then there is a V  split all along the two foot edge... now the diameter is 3.1 inches because of the space of the  V.  (NUMBERS ARE GUESSTIMATED NOT TO BE TAKEN FOR EXACTA.)

But what if i split the Black Locust 4 ways and age it a couple years before using it? Then keep a bit of expanding foam handy and stay on top of any wind that might whistle through.  Another option might be to cut the wood 7 feet long and age it two years then use it standing up for a wall.

Hardwoods if wet enough will expand enough to blow a wall apart also per Rob Roy as I recall.

Dry softwoods are better. 

Yep. Rob Roy had that problem when building with hard wood.

Yes Rob Roy and others have said that the hardwoods get bigger when they get dry..

The reason that i wanted to use Black Locust is because of its natural ability to resist decay - even when used ground contact/underground.

I should add that my comment as to why hardwoods get bigger as they dry is my own hypothesis. I couldn't find a reason so i looked at hardwood and made my own.. It would explain why people with log end walls see cracks as the wood shrinks and also explain why Rob Roy and others say that hardwood gets bigger as it dries...

So maybe my hypothesis is a working theory until  maybe someone finds a better answer.

Why has no one mentioned that termites don't like burnt wood.  Not that I suggest using wood in direct contact with the earth, but in such circumstances i.e. chicken coop, temp housing, etc, it would be feasible to burn/char posts that would be buried.  Posts have been found that are very old like this still intact.

sixnone wrote:
Why has no one mentioned that termites don't like burnt wood.  Not that I suggest using wood in direct contact with the earth, but in such circumstances i.e. chicken coop, temp housing, etc, it would be feasible to burn/char posts that would be buried.  Posts have been found that are very old like this still intact.

Good point sixnone... I believe that Mike Ohller has recommended that in his book and Paul has mentioned it.

Mike did recommend it and I did it on the ones I put in the plastic bags - about six each, but the plastic bags got and held moisture in from the still damp poles and rotted out within about 3 years - started showing damage then.  I had to replace them at about 6 years after a couple years of settling, fungi and termites.

I do not recommend plastic over any poles.  Just charred would likely have done better without the plastic.

Fortunately my ground is so hard here I stopped putting them in the ground and went to driven steel pins, vapor barrier, about 2 inches of pretty dry concrete just under the post end then temp bracing until the backfill was accomplished.

The Troglodyte wrote:
Mike did recommend it and I did it on the ones I put in the plastic bags - about six each, but the plastic bags got and held moisture in from the still damp poles and rotted out within about 3 years - started showing damage then.  I had to replace them at about 6 years after a couple years of settling, fungi and termites.

I do not recommend plastic over any poles.  Just charred would likely have done better without the plastic.

Fortunately my ground is so hard here I stopped putting them in the ground and went to driven steel pins, vapor barrier, about 2 inches of pretty dry concrete just under the post end then temp bracing until the backfill was accomplished.

That's what  i thought wud happen to wood in plastic bags... Thnx for the info.
-------------------------------------------------------------------------------------------------------------------------------------------------------

sixnone wrote:
Why has no one mentioned that termites don't like burnt wood.  Not that I suggest using wood in direct contact with the earth, but in such circumstances i.e. chicken coop, temp housing, etc, it would be feasible to burn/char posts that would be buried.  Posts have been found that are very old like this still intact.

I wasn't really planning to use wood ground contact for home construction , was just saying that it is decay resistant.. they use B. Locust here for fence posts. I used it for raised garden beds. 

I was thinking of using the Earthship  (rammed earth and tires) for the base and then the cord wood on top of that , but ran into the
problem of hardwood getting bigger after it dried.

So i wonder how much charring is the right amount If you charred too much it seems that the wood would be hard and brittle, too little and the sub T termites would smell food and dive in.

I started this post over a year ago. It was my first post on the forum, and I've gained so much knowledge since... Glen, I've also posted on your forum, if you'll look back a few months. I think it's amazing that this particular post has gotten over 10,000 views, and several have contributed to the way I look at my ever changing design.

I do eventually intend to build something along these lines, but a diminishing economy leaves it just out of reach for now. Someday..... For now I am renting a 5 acre farmstead, surrounded by state land and hoping that the extra space can allow me to mock up and pre-assemble some portions of the house prior to actual building. My end result should be something like log cabin meets post and beam, meets earth contact. I'm a classic outside the box thinker, so i never follow the directions to the letter... 

Quittrack, I also learn everyday from others knowledge on the forum. 

Since this type of building is not covered by codes and in my estimation exceeds the codes, you will not find it in many places other than forums or books like Mike Oehler's.  I ignore the ones that get into major concrete and engineering.  They are for people with way too much money.

In reality, if you use your natural resources and salvage you can still do the underground cabin very inexpensively.

On a side note, I just gave permission for pix of mine to be used in a UK school book.  We'll see if it really happens within the next year or so.

Mike's design made sense to me the first time I read about it, because I knew that the natives in Alaska and other areas used to build their homes underground of wood.  Now, they had some problems with those homes because they didn't have any good way of waterproofing the structures (so they usually lived in tents in the summer, because the underground houses got damp).  But we have plastics that do an admirable job of keeping the house dry.

Kathleen

I love this post...still new here but versed well. 

I have a rammed earth tire foundation sunk about 4 foot below grade, 16 inches thick cob wall on top of that.  Working on ferrocement roof this summer.  There has been no water penetration.  Its been up since 1999.  The stucco for the rammed tires is cement lime mix.  It is also wrapped with some roofing/tar paper, and some plastic.  And just to be sure that no water gets in, I used clay sloping away at a downward angle...then backfilled with sand and gravel.  I read a book (cant remember which one) about using clay as a sealant for underground houses.

There is plenty of good clay here.  It really does the trick, of course if your using wood without some sort of plastic barrier, it would not, and I would not.

Wood underground just doesn't seem very viable long term, to many if's, but thats my opinion.  I'll still visit if you chose to use it.

I've got 8 years in mine, and it looks like with the occasional repair it could make another hundred.

It is also strong enough I could drive my 4 wheeler on top of it with no worries.

Water problems - occasionally especially when the gophers dig a new hole somewhere around the perimeter.  I would suggest adding French drains whenever possible and extending the EPDM umbrella 10 feet or so if possible as Hait recommends in his PAHS method.  I will add them to mine around the inside perimeter of the back and side walls in 2 areas, then either drill out to the outside for the drain or just put a sump in.

Repairs are not too hard to make - even changing a post is possible if necessary.

sixnone wrote:
I read a book (cant remember which one) about using clay as a sealant for underground houses.

I would be very interested in learning more about this if anyone else out there has any information.

Bradon Wesche wrote:
I would be very interested in learning more about this if anyone else out there has any information.

Bentonite clay used for waterproofing - here's wiki link...   http://en.wikipedia.org/wiki/Bentonite

Bradon Wesche wrote:
I would be very interested in learning more about this if anyone else out there has any information.

Found it!  The book is "How to Build Your Own Underground Home" by Ray G. Scott.  The reference I refer to is on page 122 and continues for a few pages with a few diagrams.  Makes perfect sense and works. First edition 1979.  ISBN 0-8306-9744-6

I was hoping someone would have found it for me....

sixnone wrote:
I love this post...still new here but versed well. 

I have a rammed earth tire foundation sunk about 4 foot below grade, 16 inches thick cob wall on top of that.  Working on ferrocement roof this summer.  There has been no water penetration.  Its been up since 1999.  The stucco for the rammed tires is cement lime mix.  It is also wrapped with some roofing/tar paper, and some plastic.  And just to be sure that no water gets in, I used clay sloping away at a downward angle...then backfilled with sand and gravel.  I read a book (cant remember which one) about using clay as a sealant for underground houses.

There is plenty of good clay here.  It really does the trick, of course if your using wood without some sort of plastic barrier, it would not, and I would not.

Wood underground just doesn't seem very viable long term, to many if's, but thats my opinion.  I'll still visit if you chose to use it.

sixnone can you post a pic or two of this place?

ronie wrote:
sixnone can you post a pic or two of this place?

Sure, here is one for starts.

This was taken last fall.  Not a good view of rammed earth tire depth but keep in mind below bond beam is about four feet.  Originally there was going to be a second floor/porch or deck.  I can only do so much as one person.  Haven't had a lot of help through the project. Its all been hand dug...I retired a shovel...rest its soul.

I'll post more as I can.

Ooops.  How bout now?

That does look like a lot of work... What is the plan for the roof? Is it a cellar or room addition?  Is that a cement cap between the tires and the cobb?

ronie wrote:
That does look like a lot of work... What is the plan for the roof? Is it a cellar or room addition?   Is that a cement cap between the tires and the cobb?

The roof has a frame made of bamboo as a temp forming system to get the curvature I want. Over that I put www wire (?) same stuff you put in concrete you buy by the roll.  I got a steal at a local scape yard that had a full roll, saved 100$.Then I stretched burlap over that, then some rebar, with the idea of creating tension rings.  then I will go with some chicken wire and another layer or two of burlap. Coatings for ferrocemt mix with acrylic latex.

But don't want to hijack a thread that is intended for underground so I have include a picture of the in-ground portion.  Rammed earth tire. Yes that is a cap (bond beam) you see.  Did not really need it.  Tires are so solid.

It is an addition,  I bought the 4 acre place with a 71 mobile home on it.  It wont last too much longer and I really don't like the look of it plus, the insulation is not that great.  Wanted something simple, and easy to heat me, food and water.  Something I can leave unattended without utility bills...thats the goal.  When addition is done I plan on dismantling mobile home and building more cob in its place.  North to south orientation runs diagonal from bottom left (north) to top right (south).  New build will be more properly oriented.

I believe everything can be done, others don't.  I cant tell you how many people will tell you this kind of thing cant be done.  Don't ever doubt yourself!

Man I love this design... Be careful or you will have Paul out there with his video camera .

Ok so what is the plan to keep water from freezing?

Is that a sears forever shovel i see in the pic?

ronie wrote:
Man I love this design... Be careful or you will have Paul out there with his video camera .

Ok so what is the plan to keep water from freezing?

Is that a sears forever shovel i see in the pic?

Thanks.  Thats funny.

Water will be stored underground in mass.  Pex tubing and a drainback system for inactivity.  That should work.  I may have a week at most of 0 degree weather.  Usually teens to 30 degrees for 2 months.

Dont know about shovel type...just know it works.

Have you looked at any of Ernie's rocket mass heaters to use for heating?

ronie wrote:
Have you looked at any of Ernie's rocket mass heaters to use for heating?

I've got one I made 2 yrs ago, not sure I have seen his but they are all about the same principle.  I love it.  It will be in cobb addition.  It has been used in mobile home for one year.

I'm going to start a thread. No more post here exept for link.

If you want to start new thread... But for real your design is close enough to keep here IMO.