Underground housing

What if I just buy home depot lumber and build? What kind of overbuilding would I need from typical framework in order to support the additional load of earth?

I do not know to be honest with you because I thought of this myself. I have built above ground structures for my barn that was REALLY cheap (see the link regarding my 30 X 48 Barn for $4450). I can walk on that with ease and no deflection, so maybe by beefing it up a bit I could build a stick-built WOFATI. Now honestly that sounds like an oxy-moron (a stick built WOFATI), but the genius of the thing is its versatility.

I don't have time to look up the load bearing characteristics of wood, but I did the 8 x 8 beams in my house and since the beams are sharing load points (and not a single load point) it could hold over 4500 pounds. In practical terms, that is the ability of (2) 8 x 8 beams spanning a 12 foot stream and still hold up my bulldozer without breaking. That is a lot more stress than dirt spread evenly over a broad surface!

I do not think it would be that hard though. Built up framing lumber into beams has more strength then squared timbers so you could easily make carrying beams over windows and doors, then for the rafters, just go with 2 x 12's instead of 2 x 6's, or use more carrying beams so the spans were half as long. For posts...if you are not against presure treated wood, is to insert that into the 4 foot hole, then stagger the joints a foot or so out of the hole and then scab on regular framing lumber to form (3) 2 x 6's to make a built-up 6 x 6 post. I am probably not being very clear, but you would end up with the bottom 4-5 feet being pressure treated. I have seen a lot of buildings built like that and are still standing. Of course if you are opposed to pressure treated wood, you could just char it, or have rot-resitant wood like hatchback or cedar sawn out for you.

One thing I plan to do is use a membrane for my umbrella like everyone does (and rightfully so), but for the ceiling I plan to install steel roofing. This has some advantages. It adds lateral stability to the structure thanks to the seams that "lock" it together and keep the building from wracking. It would also be a second level of protection from water infiltration if the umbrella leaked. But it would also help support the soil. Steel is very strong which is why I can walk on such thin sheets on 4 foot rafter spacing's with 2 foot spacing's of purlings. I will have to look up at it as I live in my WOFATI, but we have the look in my barn and I kind of like it. And it should not rust or rot as the soil above should always be dry.

If you read extensively in Oehler, he mentions that he has a lot of troubles with gophers. You may or may not, depending where you are. But critters live in the ground, and this must be taken into consideration. Maybe a lining of hardware cloth or some other kind of wire mesh between the soil and the plastic would be helpful.

Also, plastic breaks down over time. Not so that it goes away but so that its structural integrity is compromised and it breaks into microparticles. So you might design so that in ten, fifteen years, it would be accessible to go in and replace the plastic.

Alot of issues , including cost, can be solved by building the structure in concrete block.

Its easy to learn (lego for adults) solid, Inorganic ( which helps eliminate mould ) ,critter can't get through, Fireproof ( a huge plus) and easily exolated with either foam sheets or mineral wool.

It is also easy to make a curving or circular house using blocks.

Insulating under and around the whole structure a must.

Electric heat cable can be laid in the floor slab or at least in the bathroom

On the interior finish a parge or stucco in any style or colour you like . Or raw block can be strapped and covered with panelling or surface of choice.

Important tip on insulation. Do not use foam on the inside, only outside and preferably only under ground or against ground.

If interior insulation is needed use compact mineral wool , Roxul comfortboard IS very nice and takes stucco very well as it is made from stone.

As a mason , I am always wondering why more people don't do these builds in block which is also very economical .

The groundwork is all important. COmpact 3/4 - gravel, preferably of limestone, as a base. Don't lay out more than 6 inches per layer. Keep it as level and smooth as possible.

Lay out the foam ( min. 1.5 in) two feet past where the edge of your slab will be.

Lay out steel mesh(6 in x 4x8 ft) with re bar around perimeter.

Pour minimum 5 inch slab .

You should have the slab engineered if there is to be heavy load or other special conditions.

Build your block walls on this. Let slab extend minimum 1 foot past wall and foam under slab past this.

Common or recycled brick will make nice partitions, 4 inch block also good for these.

Again, As a mason  I believe in this simple building method but mainstream building is all wooden framing with all its layers and cavities - rodent heaven!!

The exterior of the structure is easily waterproofed with a paintable membrane and then a blueskin or other heavy membrane. THe heavy industrial ones that are welded on by specialists are the highest quality and probably advisable under or against the ground.

I just wanted to add a tip about insulation. The foam should always be EXTRUDED RIGID type, do not use the white styrofoam , even if it costs alot less. It will break easily and the little balls of foam it is made of are perfect for ants to pick out. They will hollow it out.

We have Seen older white styro sheets completely gutted by ants. Only the outer shell/stucco remaining. The rigid foam is inpenetrable.

Just wanted to pass these tips along. I still see people building without insulated the foundation at all or using the white foam.

ALso that a "cob" look can easily be obtained using block and mortar and a brush.

Most trade schools/community colleges offer basic bricklaying/block courses. But its easy to learn the basics , maybe hire a local mason to get started a few days.

posting here and on 48hrs as requested. Thank you for your time. Also, I realized that I wrote "I have to know before I forget". How rude can I be. ugh!!
> I'm reading as fast as I can, but I have to know before I forget. Regarding a post from 2009 Underground Housing, did you build the structure pictured for $1k?
>
> Post by: paul wheaton , master steward
> Jun 10, 2009 07:29:23
> +1 -1 Quote Report
> So I'm combining a lot of ideas from a lot of people and coming to a new space amd I just need to express it.
>
> First, we have
>
> Sepp, building a shelter in a day (above).
>

> Total cost for the structure is about $1000 (two layers of felt and one layer of pond liner) plus the cost of the track-hoe.  Note that the soil is a meter deep over the structure.
>
> And then we have Mike Oehler's designs that are in many ways similar - with light coming in all four directions.
>
> Then add in the idea of the umbrella architecture:

below this was a picture of the dwelling

Shelah Horvitz wrote:If you read extensively in Oehler, he mentions that he has a lot of troubles with gophers. You may or may not, depending where you are. But critters live in the ground, and this must be taken into consideration. Maybe a lining of hardware cloth or some other kind of wire mesh between the soil and the plastic would be helpful.

Also, plastic breaks down over time. Not so that it goes away but so that its structural integrity is compromised and it breaks into microparticles. So you might design so that in ten, fifteen years, it would be accessible to go in and replace the plastic.

Just to clarify on this point, the poly plastic breaks down under UV exposure. Since it's buried in soil it doesn't receive that exposure and won't break down. The main issue is punctures during installation or not screening the soil you add as described in Mike's book and then that rough rocky soil presses against the material and causes a leak. As described in the book, if you have 2 layers of plastic with several inches of soil between it can help minimize the risk of water getting through both.

For critters, I think Mike mentioned that one time he had an invader, who made a straight shot to his root cellar or pantry where he had some food not properly sealed up. After cleaning that up he didn't have further issues (from what I recall), but had regular issues with them in his greenhouse.

Seen a sort of cave/cellar made in sandstone. The place never gets wet/humid, no matter how much is rains, (and it does rain a lot around here). All the other cellars I've seen around here are always damp and often have mold. This sandstone place is super simple, just a hole in the hill with a door, but could easily become a pleasant little home. Unfortunately students go there and get drunk and there are broken glass bottles everywhere. I get real angry when I see this. Something similar I was in one of the canary Island La Palma, there where caves where people used to live in, but because there were so much more people around in the area, they were somehow converted to toilets, you could see toilet paper everywhere in them, disgusting. These caves could have been great places to live in.

My one take on underground buildings is simple:  it'll eventually leak.  There are SO many variables.  Even the PAHS homes have issues - and they are only partially underground.  i spent an engineering career in commercial and industrial building operations... and even with their $$$$ budgets and toxic waterproofing materials used - eventually even they leak:  cracked floors, shifting & leaking roofs, etc.   The big issue is TIME:  you might be alright for the first 5 years - but eventually the ground shifts, shit happens, and triple+ waterproofing cracks.  Water intrusion and even worse: freezing water/moisture eventually erodes the building's substructure.
My advice:  find a nice cave, and let nature do the work, or maybe re-incarnate as a ground hog :-)

Fred Klammt wrote:My one take on underground buildings is simple:  it'll eventually leak.  There are SO many variables.  Even the PAHS homes have issues - and they are only partially underground.  i spent an engineering career in commercial and industrial building operations... and even with their $$$$ budgets and toxic waterproofing materials used - eventually even they leak:  cracked floors, shifting & leaking roofs, etc.   The big issue is TIME:  you might be alright for the first 5 years - but eventually the ground shifts, shit happens, and triple+ waterproofing cracks.  Water intrusion and even worse: freezing water/moisture eventually erodes the building's substructure.
My advice:  find a nice cave, and let nature do the work, or maybe re-incarnate as a ground hog :-)

That could be said of any building though. Eventually the roof will fail, animals will get in the walls, the plumbing will go, etc... Time wins against all of humanity's creation, even nuclear waste will eventually return harmlessly to the earth if your patient enough.

A lot of the issues with underground homes is extremely poor planning, really just not thinking it through. Thinking over application of water proofing will solve the problem of water. Or forgetting about frost heave, or animals.

You can plan ahead and build underground and earth sheltered well. You can do things like Oehler and others have figured out to head off many of the worst mistakes commonly made by those trying to build underground. You can be prepared to excavate and fix replace things if something does go wrong.

Or you could do things like Baldassare Forestiere http://www.undergroundgardens.com/about



Or you could do it like Ra Paulette https://www.atlasobscura.com/places/ra-paulette-s-hand-carved-caves



And build highly different types of cave homes using unique properties of uncommon types of earth and then use methods similar to any burrowing animal does to control heat and cold and water.

My point is, it is easy to say something will happen, but you can plan the best you can and be prepared to fix what has to get fixed. As well as remember most stick homes these days start to fall apart 5-10 yrs. They sure don't make 'em like they used to.

This is why the home I am designing to be an earth sheltered home is basically a timber frame home. Timber frame lasts 100's of years if done right. It is extremely good at baring heavy loads. In an earth sheltered situation, it could handle being unearthed and reburied.

Mike Oehler spent 30 years in his underground house (which the wofati is based on), and passed on what he learned compared to building the "first thought house" that most underground houses are based on, with water penetration the #1 issue. While it's inevitable that a leak will develop over the years/decades, that's true of any home. A big tree branch can fall and puncture the umbrella sitting a foot under the soil surface, and can also fall through the shingle/sheeting roof of a typical frame house. A french drain sitting at the edge of the umbrella could be poorly installed and fail to drain or clogs up and lets water back up under the insulated mass or even worse reach the buried posts. Or the building is placed in a flood plain or in a location that a french drain can't handle.

But all of those issues are either out of your control or due to poor planning/design, and not so much due to structure itself.

I just want to state that this thread now has 702,726 views.

I remember when this forum was super tiny - I was just starting it.  And I saw in another forum a fella tried to ask about this stuff and he was shouted down in a particularly ugly way.   So I wrote to this person and invited him to post here - and told him he would not be shouted down.

This is thread number 959.  So when this thread started, there were not yet 1000 threads on this site.  And now there are over 100,000.  

I just had a warm, fuzzy feeling to share when I saw this thread being bumped.

That is awesome Paul. Thanks for putting this thread into perspective.

If I had an excavator** or a bunch of strong young backs, I'd site a PAHS 'umbrella' house on southwest sloping land - for max winter solar gain.  I'd only put 1/2 half (the north side) of the house underground.  I'd put in a deeply anchored rubble or cinderblock wall (maybe two walls with a french drain in between) on the north side and/or a combo of Sepp Holzer's root cellar designs to prevent future 'mudslides'.  the airflows and thermal mass storage of the PAHS are ingenious... ( The initial PAHS concept came from   Dr. Hiatt of RMI in the 1970's) .   The underground roof part would be tricky... eventually it'll leak (just ask the GAP facility manager who maintained the first green roof in South San Fran in the 1980's) - plant roots are amazing and water will follow!    ....when the 'bird of paradise' deposits  some willow or elm tree seeds on the roof...

**  Excavation is the cheapest form of construction.

Has anyone tryied to build a Kiva-style home? Or a Hogan-style home. The kiva is essentially a hogan-like many-sided or round stone structure build underground, with a hole in the roof to enter. Hogans are octagonal (or maybe more sides) log structure, and the roof is constructed by reducing the diameter with each successive layer of logs., until the hole in the center can be bridged with logs. it uses a LOT of large logs! I'm wondering if a Hogan structure would be strong enough to be buried?

Fred Klammt wrote: **  Excavation is the cheapest form of construction.

Particularly if digging initially involves mining for opals and the resulting tunnels and holes become well insulated homes:

https://www.outback-australia-travel-secrets.com/coober-pedy-underground-homes.html

Susan Monroe wrote:One thing I just read was a link from this site, Capturing Heat While the Sun Shines, to Warm Your Home Next Winter
at http://greenershelter.org/index.php?pg=3

This article may have some bearing on what you're trying to do.  Be sure to go down to the very bottom of the page and click on "Requested Paper for the Global Sustainable Building Conference 2005, Tokyo, Japan, Sept. 2005" for more details.

It sounds like you're planning on buying an existing house and moving it to the site, is that correct?

I don't have any excruciating interest in underground homes, but I've read about a few.  And if memory serves (always an iffy thing), all of them seemed to have an outer shell of stone or concrete.  EXACTLY how do you intend to deal with the termites? I just have a funny feeling that it isn't possible to bury a wooden structure underground without them causing a major problem.  My main issue is the weight of the (rain-soaked) soil on top of a termite-damaged support structure. 

Great strides have been made in thin-wall ferro-cement in the last twenty years or so.  Do you think it would be possible to place a wood-framed home on a concrete pad, and then form an outer shell of concrete?  It might not have to be very thick... maybe.

It's an interesting concept, but without an ironclad plan against the termites, I'm not sure this would be feasible.  And I don't think being trapped (sorry) underground with poisons would be a good thing.

Have you ever investigated stone/concrete slip-form building (I think that's what it's called)? I know there is at least one book on the subject, although it may be out of print. Build your perimeter and supports this way, then backfill it the way you planned?

Here is one site on it:  http://www.hollowtop.com/cls_html/stone_home.htm

I would like to hear more about this, what your final plan is, how you do it, etc.  Low-cost housing is something that many people would be interested in.

Sue

One thing you didn't mention is ventilation.

Miners had to dig vertical tunnels to allow for fresh air into a mine.

If you remain in a closed space (aka your nice insulated AIR TIGHT space), you could suffer from suffocation. You also will have humidity skyrocket (mold issues too).

There is also a Radon Gas issue depending on your geographical area unless you are air tight.

Dirt is indeed a thermal mass. BUT it has low temperature swings 5 feet down or lower depending on your zone. Stone is best for even temperatures underground. Caves are pretty much ideal.

One guy (youtube) made a hugelgarden and next to it he dug 5 foot trench a few feet wide. He then drew plastic sheeting over all that and suspended it above his normal raised bed gardens adjacent to the Hugel/trench arrangement. Kept his garden growing all winter.

In the dead cold, the outside temps were quite COLD. But the bottom of the trench was a balmy 55 degrees F.

I could live in 55F year round pretty easily. Supplemental heat in winter and blankies in the summer.

https://www.offthegridnews.com/survival-gardening-2/an-underground-greenhouse-its-not-just-a-fad/

Same principles apply to insteading (what you are trying to do).

You must have an air exchange!

Relying on an electric fan is ill advised. If the fan fails or your supplied power fails, you could be in bad trouble.

Now, you could install a rocket mass heater/stove combo with piping from outside for combustion and ventilation as well as exhaust piping.

Even if the stove isn't lit, you can still have some natural ventilation. But you need 'makeup air' in all cases.

Or just a small vent tube going up through the 'roof' and another one coming in down low.

Some information:

https://www.houzz.com/magazine/how-to-artfully-build-a-house-on-a-hillside-stsetivw-vs~17696835


Might I suggest you have 3 sides in the ground and one outside the ground (for view, easier access, ventilation, safety, etc?


You might need a geologist to determine the ground water levels, strength of the surrounding rock, etc.

I have seen pix of houses built on relatively flat ground and then nearly covered over with dirt.

https://www.zillow.com/blog/hobbit-house-222609/

Here is one from youtube:

There is a series of forts built along France's Eastern border in the late 1800's. Some were built by the French, some by the Germans, and they were all built in-ground with enormous Earth berms. The idea was to be resistant to shelling and hard to spot. They became obsolete with the advent of aircraft.

The construction was vaulted stone masonry. The buildings themselves were two or three stories tall, all with a couple meters of earth bermed from the exterior up over the top, leaving large interior facing courtyards.

All this without plastic membrane.

I have visited three of them. Some of the interior space is rented out as offices and art space, but even the unrenovated sections are still in solid shape. So why can't we build houses like this? Where's the dreaded water leaking in and tree roots crumbling the structure? These places are covered in forest!

You can Google "fort de tamié", "fort du mont, Albertville," or "fort Kléber" to see the ones I've been to.

Nathanael Szobody wrote:There is a series of forts built along France's Eastern border in the late 1800's. Some were built by the French, some by the Germans, and they were all built in-ground with enormous Earth berms. The idea was to be resistant to shelling and hard to spot. They became obsolete with the advent of aircraft.

The construction was vaulted stone masonry. The buildings themselves were two or three stories tall, all with a couple meters of earth bermed from the exterior up over the top, leaving large interior facing courtyards.

All this without plastic membrane.

I have visited three of them. Some of the interior space is rented out as offices and art space, but even the unrenovated sections are still in solid shape. So why can't we build houses like this? Where's the dreaded water leaking in and tree roots crumbling the structure? These places are covered in forest!

You can Google "fort de tamié", "fort du mont, Albertville," or "fort Kléber" to see the ones I've been to.

The term we have today is called 'designed obsolescence'.
They want to make cheap housing, sell it for a high price, then get you o repairs down the road.
Same way with old appliances vs new ones. Tools too. Cars, everything.
Anything to get your money as often as possible.

About those bomb shelters - how thick were the walls and ceiling?

They also used excellent concrete - not the poor grade stuff we use today.

They also let it cure at one inch per day too back then. Slower the cure the harder and longer it will last.

Today they usually add chemicals to give it a fast cure.

And the steel reinforcing is sub grade steel and not even galvanized.

Kai, so what you're saying is, we could build that way today. I'm just hating the whole plastic membrane thing.

The walls were about 1 meter thick--two walls actually, with a rubble and mortar mix in between.

Nathanael Szobody wrote:Kai, so what you're saying is, we could build that way today. I'm just hating the whole plastic membrane thing.

The walls were about 1 meter thick--two walls actually, with a rubble and mortar mix in between.

well you could mix up some cement and line it that way.
All natural.
Just check on the source and see how much lead and stuff is in it first.

Plastic can have some value in certain circumstances. I prefer not to use any but if I have to then I will.

Sometimes there is no reasonable way around it..

If you line your garden with cement, you might want to make it 4" think or thicker to handle the weight.

Did you know that some people make their hugels out of horse watering troughs?

this is a good idea until it rusts out:
[youtube]
https://www.youtube.com/results?search_query=watering+trough+garden[/youtube]

Kai Walker wrote:

Nathanael Szobody wrote:There is a series of forts built along France's Eastern border in the late 1800's. Some were built by the French, some by the Germans, and they were all built in-ground with enormous Earth berms. The idea was to be resistant to shelling and hard to spot. They became obsolete with the advent of aircraft.

The construction was vaulted stone masonry. The buildings themselves were two or three stories tall, all with a couple meters of earth bermed from the exterior up over the top, leaving large interior facing courtyards.

All this without plastic membrane.

I have visited three of them. Some of the interior space is rented out as offices and art space, but even the unrenovated sections are still in solid shape. So why can't we build houses like this? Where's the dreaded water leaking in and tree roots crumbling the structure? These places are covered in forest!

You can Google "fort de tamié", "fort du mont, Albertville," or "fort Kléber" to see the ones I've been to.

The term we have today is called 'designed obsolescence'.
They want to make cheap housing, sell it for a high price, then get you o repairs down the road.
Same way with old appliances vs new ones. Tools too. Cars, everything.
Anything to get your money as often as possible.

About those bomb shelters - how thick were the walls and ceiling?

They also used excellent concrete - not the poor grade stuff we use today.

They also let it cure at one inch per day too back then. Slower the cure the harder and longer it will last.

Today they usually add chemicals to give it a fast cure.

And the steel reinforcing is sub grade steel and not even galvanized.

I am not so sure...

A lot of what happened in the years past was, they had no real scientific way to test their ideas, so they over-built things. That is okay, such as the Empire State Building; they had no idea what the stresses would be, so they doubled everything. It literally could go up another 100 stories. That is fine, except it was also 100% wasteful. That is what engineering is; designing something to support the intended load, granted with some redundancy, and no more. Any more is wasteful. I mean why use 5000 PSI concrete when 3000 PSI will work? It is not stronger, it just has time and money making it 40% stronger for a load it will never see.

But there is another aspect to underground building...or any building that I do that I must ask myself...How Hard is it to Redo?

For instance I just built a bridge that was made out of wood, cost me $16.50, and took only 8 hours to build. People on another forum wanted to know how long it would last. What point of taking 1 day to build, and costing $16.50 was missed? I could build a replacement every ten years for fifty years and not come close to what a plastic culvert would cost. And who is to say in 10 years, it will be even easier, faster, and cheaper to build? In the meantime, I am using a bridge.

And that is why I do not have an issue with underground houses either. Really how bad would it be to take an excavator and peel off the soil and redo the sealing method of the house again? It is a quick, fast, inexpensive job today: I cannot imagine it will be harder 25 years from now. I do not expect to live in my conventionally built homes for 30 years with no work, why would I ever expect that from an underground house?

But when, and if I do build an underground house. I do not plan to use a plastic liner however. Here we can get steel roofing cheap, and it last forever on a roof as is. I plan on using that, in part because I like its tensile strength, but also how its ribs lock the building together and keeps the building strong and resistant to twist, and how it is lightweight and waterproof.

Travis,

Steel roofing? You mean like the galvanized stuff? That will rust in very short order when moisture is held against it. Even stainless steel will rust when buried.

Nathanael Szobody wrote:Travis,

Steel roofing? You mean like the galvanized stuff? That will rust in very short order when moisture is held against it. Even stainless steel will rust when buried.

Yeah I suppose that will not work will it, kind of like pine siding on a house, it will last forever as long as air dries it out now and then. Asphalt does the same thing. The Federal Government pays to grind up hot top, but bury it in the ground and it disintegrates in a few years time.

I will keep thinking about this problem, although it looks like plastic.

I got to thinking about this, and I was wondering why there would be moisture in the soil on top of the steel roofing?

Just so everyone understands what I would be doing with the steel roofing, I would be using it as a ceiling/support of the earth above. I would also put 2 inches of styrofoam insulation on top of it because the University of Minnesota did studies and found that was a superior underground build. So as I plan it, the soil would not be in direct contract with the steel roofing. But even if it was, how much moisture would there be? The home is pumping out heat at 70 degrees 24/7, so the soil trapped between the steel roofing and the initial membrane would be most likely dry...very dry.

I could see where moisture from life in the home: cooking, cleaning, bathing, etc would pump some moisture in the air, but that is the same problem ultra efficient homes have too, and they just put their bathroom power vents on a timer to exchange the air on 30 minute intervals. I would think for an underground house, that would be required as well...but hardly a big issue.

Travis,

Does it not rain there? The soil biology makes it rust--in party due to the acids they create. That's what soil biology does: mines rock for minerals.

If you're using styrofoam, might as well use plastic too.

Nathanael Szobody wrote:Travis,

Does it not rain there? The soil biology makes it rust--in party due to the acids they create. That's what soil biology does: mines rock for minerals.

If you're using styrofoam, might as well use plastic too.

But that does not make sense to me fully. For instance, when I finally got around to logging some old growth forest I had, the ground was red shortly afterwards. When a wetland specialist was here to determine if wetlands were in the area, he saw the red color and mentioned that this had been old growth forest, he knew because the iron in the soil was churned up and rusting. If the area had been logged before, or had been used as a tilled field, or even as a pasture, the animals hooves would have kicked up the dirt, and it would have rusted. It was confirmed old growth because the iron had sat dormant in the soil.

I would say that maybe the iron is rusting and I just cannot see it without the soil churned up, but then why is it still in the soil?

I would think the rate of rust would depend on how much oxygen is in the soil. I know if we bury stumps deeper than a foot of soil, they will not rot. That is why a lot of Hugels fail, people compact the soil too much and decay stops.

And just last week I dug up some wheels off a cart that have not seen the light of day since the 1800's. If steel rusts to oblivion in soil, how come I was able to find them, and a ton of other stuff from the 1800's off this farm?

What you suggest just does not match my experience with steel in soil.

Will your metal roofing not be exposed to oxygen from the INSIDE?

I asked a friend what they used for earthen roofs in the olden days.  They came back with birch bark.  I don't know much about it but I do know that birch bark doesn't compost hardly at all when it gets into my compost pile.  I'd imagine an overlapping shingled birch bark layer could do a decent job of keeping moisture out of the dirt below it.  I don't know if the moisture would wick back up between the layers and get through to the soil beneath.

When I was at the PDC, we had some discussion about natural moisture barriers for Wofati. Like a lot of permies, using pond liners or billboard tarps or any other man made thing seems like a compromise. We even thought about some ideas for natural insulation layer.

What we sort of came up with as natural idea for moisture barrier was some sort of man made caliche.

https://en.wikipedia.org/wiki/Caliche

Caliche is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt.

Forming some sort of caliche as a barrier against water might be a long lasting and nature way to do a wofati.

As for insulation, we had a thought of using biochar.

It would be interesting to see if this could be done and work. While I would love to do it for the home I am planning to build, I am thinking I might want to do a small scale test structure and then if it works, since if it fails for a home, that could be rather catastrophic, and Murphy's law says it would happen at the worst of times.

Mike Jay wrote:I asked a friend what they used for earthen roofs in the olden days.  They came back with birch bark.  I don't know much about it but I do know that birch bark doesn't compost hardly at all when it gets into my compost pile.  I'd imagine an overlapping shingled birch bark layer could do a decent job of keeping moisture out of the dirt below it.  I don't know if the moisture would wick back up between the layers and get through to the soil beneath.

Have you ever done a forty year compost pile with birch bark in it? I would think that forty years is a good target lifespan for a natural house.

We have lots of slate here, but it is only going to add to the weight of the structure.

Devin Lavign wrote:When I was at the PDC, we had some discussion about natural moisture barriers for Wofati. Like a lot of permies, using pond liners or billboard tarps or any other man made thing seems like a compromise. We even thought about some ideas for natural insulation layer.

What we sort of came up with as natural idea for moisture barrier was some sort of man made caliche.

https://en.wikipedia.org/wiki/Caliche

Caliche is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt.

Forming some sort of caliche as a barrier against water might be a long lasting and nature way to do a wofati.

As for insulation, we had a thought of using biochar.

It would be interesting to see if this could be done and work. While I would love to do it for the home I am planning to build, I am thinking I might want to do a small scale test structure and then if it works, since if it fails for a home, that could be rather catastrophic, and Murphy's law says it would happen at the worst of times.

Honestly, I think this would work. Basically, its lime concrete. Not that it will never crack, but it will fill it its own cracks with lime crystals--self-repair, in other words. The key would be to make the wall and ceiling in masonry. It would have to be vaulted. Then, if water is ever leaking, you actually see it trickling down the wall. The edge of the floors around the walls could even have a  moulded dip in them to take eventual moisture to a drain.

I built a water tower with brick and mortar. No concrete, no rebar. It cracked, as expected. Water leaks only when it is nearly full and the pressure has built up. Otherwise, the cracks have calcified and it holds back mild pressure. Why not a roof with moist dirt on top? Add a layer of limecrete over the masonry vault, cure it well and cover.  

Nathanael Szobody wrote:

Mike Jay wrote:I asked a friend what they used for earthen roofs in the olden days.  They came back with birch bark.  I don't know much about it but I do know that birch bark doesn't compost hardly at all when it gets into my compost pile.  I'd imagine an overlapping shingled birch bark layer could do a decent job of keeping moisture out of the dirt below it.  I don't know if the moisture would wick back up between the layers and get through to the soil beneath.

Have you ever done a forty year compost pile with birch bark in it? I would think that forty years is a good target lifespan for a natural house.

Nope, just a year or so.  The main idea is that since it was used in the distant past for sod/earthen roofs, at least it's an option to consider.

For fun, I doodled a retirement home for my wife and I yesterday. Not all the details are right just yet, but while it is a very simple and small underground house, its shaping up to be a nice build. It will only be 28x 24 in size, one bedroom, one bathroom, with a shared kitchen and living room. It will also have a shed roof for simplicity, a concrete slab with radiant floor heat, and will be timber framed.

There is a high probability of us actually building it because our town has no building codes so we can actually build what we want. With the type of people we have in our town, that does not look like that will ever change, so we should be good there. But we also have a gravel pit, and a sawmill with our own woodlot, so we can produce most of our own building materials.

We even have a site picked out, a place on top of a hill, but with only a few inches of topsoil so we can build the structure on top of bedrock, but has a nice view, a southern exposure, and a four season road going to it, and is within 250 feet of the power grid. We may, or may not go off-grid, I am not sure, but it is always good to know that it is possible in the future without costing a lot of money.

We always wanted a house up there, but with it come a major issue: WIND! Building underground was really the only viable solution we could come up with to deal with the wind!

Katie and I discussed where we should situation the underground house, and after a little bit of discussion, decided at the very top of the hill would be the best spot. It has the best view of the Western Mountains (Mount Washington), and yet is close to the power grid if we decide to go that route. It also has a road, but is not well graveled, but that is easy to fix.

The other location had a better view of Maine's Northern Mountains (Mount Katadin), but was situated quite a bit farther from the grid (1000 feet instead of 250 feet). It has a better road leading to it, but it would be longer to traverse as it winds its way up the hillside.

This is where we want to situate the underground house. The picture with the sheep is looking due North, and the picture with the baby is looking due South. Sorry about the baby, but I normally do not take pictures of boring ole hayfields. It does show though that there is plenty of southern exposure.

What is not apparent is the wind exposure. This hillside is so windy that a power company wanted to put (3) mega-wind  turbines here in this field, but the town voted them down. My Uncle has a small wind turbine and gets about half his electricity from the wind, and he is on the lee side of the hil!! The wind ALWAYS blows here! We are located at the height of land a few miles from the coast, so we are always been the warm and cold fronts of the Gulf of Maine, and Maine Land Mass. Really the only way we see surviving up here, would be to go underground.

I just recently found out that conventional construction has standards for and actually builds wooden basements.
Call "permanent wood foundations", they look a lot like the stick built WOFATI mentioned earlier in this thread.

William Bronson wrote:I just recently found out that conventional construction has standards for and actually builds wooden basements.
Call "permanent wood foundations", they look a lot like the stick built WOFATI mentioned earlier in this thread.

When I was out in the mid-west at a home building center, they had a design book on what amounted to a pressure treated wood basement. I bought it because while I do not like pressure treated wood, I have plenty of wood types that are rot resistant like white cedar, and hackmatack. Not always, but most of the time I can substitute boards for plywood, so I can build naturally using naturally rot resistant woods with wood coming off my sawmill.

I have no idea what happened to that booklet, but I remember reading it, and realizing it would be a very easy to build a wooden basement.