wofati eco building

Some drawings from my friend geoff badenoch. 

So, this would be early in the build.  The structural poles are in and the poles to hold the dirt are starting to go on.

Geoff's images use logs with bark, although I think wood without bark would be better (and look brighter).

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New to the forums here.......so you have not actually built this yet? I was thinking of crossing the pass in a few weeks to attend your workshop. Though I doubt my husband would ever consent to this style of building, I am very interested in earth sheltered technology.

Most of the design is based on the works of Mike Oehler.  Many Oehler structures have been built.  And I have videos of several on his property in Idaho.

A wofati would be an oehler structure, with a few changes.

Speaking of Mike, I got the DVD set, and he added the greenhouse book!  I'm thrilled, because I had that book on my list to get later!  My DD has been watching the videos (she's autistic, loves how-to-do-it videos) and I've been listening to them as I work, getting ready for a bunch of company next week.  Lots of good info in those! 

Kathleen

I just started an Appropedia "stub" page on  wofati buildings - stub meaning that it's just a useful link or two and a very brief intro to the subject. It would be great if anyone was inspired to expand it- just click "edit" and add - you don't even have to register.

Here's the article: Wofati eco building


Questions about the building: They look like they'd be a bit dark inside - if you wanted skylights, how complex or expensive would they be? and how would you go about it, and be sure not to have a leaky skylight? Leaking heat would be an issue as well - you'd want maximum light for the heat loss.

First post here, so this will have to be my introduction as well...

I am in the process of building a modified Oeher style underground home (and I disagree that is an offf putting term or in any way inaccurate.. ) which is also on a steep slope which I hope to use for a forest garden via Sepp's methods..

I had also thought of extending the dry earth barrier some distant, purely for concerns of water meeting wood, but I am thrilled to discover additional insulation value as well. I was able to get some polyethylene at a great price, all black and 10 mils thick which is 2.5 times what Mike used in his $50 underground house, and even more than he was suggesting before he began experimenting with EDMA.

I suppose I should look for the thread on french drains to offer up my objections to their descriptions... but suffice it here to say that I will be relying upon them for excess surface water (as is the case in every installation of french drains I have done or ever heard of...if ground water is getting so high that it would hit a french drain, then necessarily it could never drain any water at all! )

Instead of wood duff per se, or the earth that Mike suggests between roof layers, I am planning on using rice hulls which are readily available where I am, and which are remarkably inexpensive. To protect the poly, I am planning on using brown paper feed sacks available freely from a neighbor who has cattle.

Two thirds of the south wall (also the uphill wall) will be glass, but I have little concern about heat loss or gain even with that much glass on that side. As for heat gain, the trees on the uphill side will protect from any direct gain, and as for loss, well with most of the house underground, there is such an efficiency as to handle some loss. On the north downhill side there will also be some windows (gable end as well a one hollywood wing) which will allow for more light and of course the wonderful views.

Even though I am already in the building stage (with luck the final excavation will happen this week) I really appreciate all of the information here. Thanks to Paul and everyone else..

I have no experience with rice hulls, but the numbers are pretty good. I bet they'll be great for you.

After more thought on it, I am considering back filling with the rice hulls with earth on top, say the top couple of feet. As' the rice hulls break down I can add earth of course. This gentle adding should make rips in the plastic completely avoidable, and at the same time make backfilling VERY quick (maybe a day or two at most of back filling... See any problems with this approach?

While I do not dispute experience, I do not understand the rational of plastics use here... bags, liner, etc. would trap moisture, which is present, and it would seem, hasten the rot process?

I am now convinced thanks to the experience of folks here, not to go with the bags, though I honestly doubt whether my well cured wood would have enough moisture to be a problem. Instead I will go with the vapor barrier which not being enclosed will keep moisture on the earth side away from the wood, and allow any on the inside of the home to evaporate.

Vapor barrier is a great solution, though I've never seen a product intended for constant moisture exposure... which is why it is a vapor barrier, not a water barrier. It's funny that 3D renderings and engineered building products are making their way into a discussion about primitive huts- Pine Tar?

All water barriers are vapor barriers even if all vapor barriers are not water barriers..

Yes I am using a "water barrier" in the form of 10 mil polyethyline and probably something else, perhaps something like what is used in conventional stick built construction between the foundation and sill plate, for under the posts. I don't expect to collect enough moisture inside the home for the plastic to cause any problems.

I do recognize that I have some advantages here as well, for the site is quite steep, so moisture is taken away very quickly even in the hardest of rains. The soil here remains powder dry just about 16 inches down anyway, meaning that as long as the top portion of the home is protected, the plastic lower down will never come into play. Finally I am also looking into a dehumidifier as a last line of defense and a supply of "distilled" water, thus reducing the already small threat from interior moisture.

The shower, which would be the primary introduction of moisture into the home will be vented with a powered fan. Cooking for the most part will be done outside a window, much like Mike Oehler's own design. This leaves very little cause for the introduction of moisture into the home.

All of these elements combined leave me confident that I won't have rot problems due to condensation on the plastic.

Not sure if I'm following here or not..... but

So your underground house built along the lines of ]Mike's instructions (http://www.undergroundhousing.com/) must have internal moisture issues..... Mike addresses this, but people may still be concerned.

In this case I would not change the building design, but include good venting as part of it. 

or build in a desert.

The act of living in a home creates moisture, whether from showers or cooking (the two biggest contributors) or merely from the water vapor from our bodies. Since we are dealing with cooler surfaces in an underground home one of the first concerns or objections raised is that of condensation on the plastic which keeps water from entering the home. I tend to believe that unless you live in Houston, Texas or a rain forest, simply opening doors and windows is plenty to keep moisture problems down.

That said, since it does not interfere with how I want to live, I am incorporating very inexpensive safeguards as well. I want to cook on the outdoor fire outside the window, and a powered vent in the shower area is inexpensive and easy to install.

In regard to moisture I think the big brains have done their work. I just wonder a couple things that may or may not be of note

#1 could a desiccant be of help?
how bout bales of hay, moved from high air movement locales in the home to the green house or garage?
#2 would a point of condensation, kill two birds with the same rock? Ie; a copper pipe exposed to the outside temps. with proper frillage on both ends, so as to be good collectors and receivers. I like more usable water out of the air!
#3 is a lighting change over the shower a good idea. Lets play survival distillery shall we. If you use a medium  over the shower, and orient it in an upside down fashion,why cant it drip a lot of your evil moisture down the drain.
  Beyond this line I want to hear from the go getters who placed an add in the local add paper, who got more used pool liners, than they have home and out building dreams for.
Old pool liners Hmmm! OK OK Im New Here Yall Ya probably heard it a thousand times. I just got all these ideas, and my head hurts. AND YOU FINE FOLKS AREN"T CALLING ME WACKO yet!
I don't mean to bleed here, but just seems to me that with all these fine minds, we should surely be able to find a hugely better way forward.        May the masses wake up and follow common sense !!!
Can I say tyranny sucks here?

Paul I aint pretty, but dambit, I mean to shake your hand. You live in an out of the way spot. Ok fine I'm coming to see you! Spring is almost here. Life will renew. Mankind has yet time to make a reasonable attempt to be harmonious. I aint talking carbon BS or chains on my Brothers. Im talking about GMO. military sponsered spider goats, and a host of other apparitions that are in most folks diets today.
I have yet to see a thread on D.U.  Does a platoon have to die before your eyes, before that and others is spoken of. 
Sorry here but this hush hush so called poilitical stuff affects us all. A good soul with D.U. makes his wife a cancer victim and his child a freak with 3 legs.
You can talk poop all day long about what you know you will be supported by. Question is will you grow to the horror of what our govt. has supported.
  Don't Dumb out here! 25% of THEM are now, born as freaks. Iraq Is a land radiated from hell from our D.U. weapons. The next generation is expected to be around 50%
Pay no attention to the fact that our munitions in contraverse of guidlines by our own Govt say this stuff is a deadly plague of last result. Chill Dude it is a mere 50 Billion years. all will be fine by then no doubt.

#1 could a desiccant be of help?

What did you have in mind?

So, when indoor temperatures (during winter) are mentioned/predicted for wofati house structures, do we have more specifics like degree days, specific locations, r-values and heat loss calculations?

Or are these extrapolations from other/similar Oehler projects?

Thanks in advance,

troy

Behold!  The Psychrometric Chart!

Example:  Lets say it's 70° and 50% humidity in your structure. Find 70° on the upper left side and follow the line down vertically until you get to the 50% humidity curve.  Look right and you see you have 55 grains of moisture per pound of dry air.  Look left along that horizontal line and you find you get to dew point, 100% humidity, condensation, at about 51°.   Try other temperatures and humidities to get a feel for how this works.

You can use this chart to figure out what the dew point will be at any given temperature and relative humidity.

Too many people think that water will vent out rather than condense (and grow mold) on a cool surface.  This chart is how you tell what will really happen.

The key is to keep the interior surface temperature high enough that moisture in the air never finds a spot below dew point. 

The worst thing is if it migrates through a wall and gets to dew point temperature while inside the wall.  Then the condensation will happen inside the wall, and that's where rot and mold will grow.  This happens most when there is air movement through the wall, carrying moisture.

The best strategy is to prevent moisture at it's source, by venting cooking and bathing moisture, and by using good membranes to stop ground moisture from penetrating the building.  Foundation drains should drain to daylight.  There must be good drainage planes on vertical foundation surfaces.  Interior and perimeter drains should be through separate lines.  Floor drains should be separate from both of those.  The above ground layer of your house with the lowest moisture permeability should be on the (warm) inside, and any moisture that gets through that should be able to dry outward, driven by the small amount of heat escaping through the walls.

Having the whole place underground is going to make it hard.

Dan

How about a temperature/hunidity/dew point calculator?

http://einstein.atmos.colostate.edu/~mcnoldy/Humidity.html

The page may be saved to your computer as an .htm file and run from there.

It is considered valid for
air temperature:  0 °C < T < 60 °C
rel humidity:        1% < RH < 100%
dew point temp  0 °C < Td < 50 °C

I have a few concerns for the wofati design.

1 - Extending the umbrella on the uphill side of the house.
John Hait's umbrella design hinged greatly on the fact that heat moves very slowly through dry earth - supposedly 20 feet over 6 months if my understanding is correct. This is the reason for the umbrella extending 20 feet in every direction.  By not protecting the uphill side of the house from water, you are not only cutting the thermal mass in half, but allowing the heat to take a shortcut from inside the house to outside with very little thermal inertia. This shortcut wouldn't allow the remaining thermal mass to charge nearly as much as it would otherwise (even if the waterproofing only extended 10 feet).

2 - Too much weight for a pole structure.
From my understanding, pole structures are meant to be lightweight structures. This is why they can get by without having a foundation. When you have a green roof, you have a tremendous amount of weight on each of these poles, which act as stilts effectively. I predict that the weight would simply push these stilts deep into the ground, and your house would have some major issues with sinking - it's simply not buoyant. Either it needs less force pushing downward (a more conventional roof) or more surface to push against (a full foundation). Also, don't forget to consider soil type.

3 - Calculation of the r-value.
This one isn't nearly as significant an issue as the previous two issues, but when calculating the r-value of the roof, I don't think the dirt above the upper layer of plastic can be counted as insulation. During dry periods, the calculation would be fine. The problem would occur when it is raining, and the outside temperature of the rain penetrates the upper layer of dirt with ease. This would cause any heat in that upper layer to transfer into the water and be washed away. Again, a minor issue in my opinion due to the low calculated r-value of that dirt, but something that should be taken into account.

These are meant to be constructive criticisms, so if they come off as at all negative, I will try to rephrase. I think the work you are doing with trying to push alternative building designs is very good and needed. Keep up the good work!

Paul-
Looking forward to your hour long ++ interview tomorrow on TheSurvivalPodcast.com about wofati building.  How cool is it that Jack say's you're probably his most popular guest?

Paul, pole construction swapped with ferro cement watertank like construction might make the whole thing a little easier to put together. Not as 'green' as your construction method, but not overly expensive, easy to spread the umbrella out, inherently waterproof with the right mix and reinforcing material. I think making it like a sunken igloo with a simple pipe out the top could solve most of your internal moisture issues. Just a few thoughts to add for now.



On a side note, if you wanted to be brave, you could build a tube in a tube and raise fish in your walls

I am new to this thread, as well as new to eco building.  I have been an architect for over 30 years and understand the concepts and theories presented, but being detail-oriented, would like to hear and see (particularly see) real time designs and results (those that worked, failed, or are just problematic).  I admit that I have not looked at ALL the information out there and that I have much work to do before I build my underground, earth-sheltered, PAHS, eco-integrated abode.

The discussions about the good and evil of building codes are understandable, but not really helpful.  If we, as a community of alternative designers and builders can build a body of information, perhaps we can convince others that there can be alternatives to "conventional" construction that meet the intent of the Code.

Excellent follow up show with Jack at thesurvivalpodcast.  And look forward to the rest.

Constructively critical thoughts:

Duff, while inexpensive, will not do the same job as high density styrofoam, as advocated by John Hait in umbrella houses.  For "cold climates" he suggests r-20 in styrofoam above/around the earth/thermal mass.  That's at least 4".

My experience with "conventional" above ground houses built with r-50 levels of superinsulation suggest that no amount of thermal mass will fix the absence of good insulation. 

This does not mean that your wofati concepts are not LEAPS AND BOUNDS better than the current status quo.  Of course, it is worthwhile saying that the status quo is hideously bad, from a thermal performance point of view.

The use of duff in a wofati structure, where the average weekly temperatures are above freezing might work beautifully.  But in the sustained cold climates, I think you will regret not having the insulation. 

I just don't want to see your first built example (in a cold climate) to overpromise and underdeliver.

Which brings me back to my prior question.  Where exactly do the numbers come from for your predicted indoor winter temperatures?

Finest regards,

troy

TofiKrol wrote:
The discussions about the good and evil of building codes are understandable, but not really helpful.  If we, as a community of alternative designers and builders can build a body of information, perhaps we can convince others that there can be alternatives to "conventional" construction that meet the intent of the Code.

Hi,

Thanks for your thoughts. I do believe it is helpful for people to at least understand why building codes are in place. It gives a reference point on which to build upon when approaching building officials with alternative designs. Whether people like it or not, it's part of the process when building in areas that require permits and the more informed people are, the smoother sailing it'll be on a personal level and the entire alternative building/design community.

Re your comment on "body of information", I'm not sure I understand what you mean. "Wofati" aside, there's a tremendous amount of readily available info on alternative construction and design from hobbyist, architects/designers, builders and engineers alike from books, DVDs, the Internet and workshops. Unfortunately, most of it is either completely unknown to the masses or downright ignored.

In terms of "convincing others", one of the larger pieces of the puzzle in my humble opinion is getting alternative designs through the permitting process so these places can be built in populated areas that will receive attention by the masses. Last year, I helped an individual with a passive solar strawbale home in a metropolitan area with a population nearing 500,000. The owner tells me he is worn out from all the attention he's getting. Few people would have known a thing about that house had it been built in a remote area having no code enforcement. Had the owner gone with his initial preconceived idea with building codes though, he'd be living in a conventionally built home now, turning a technological derived dial to stay warm and cool while incessantly burning up resources. Instead, he enjoys year round comfort with no dials or need for them. People who see and/or feel this for themselves are amazed this can be done without expensive energy-hungry gadgetry.

That said, yes I do believe it is helpful and very important to talk about codes and the permitting process so these type of solutions reach a wider demographic. There's no excuse why every home built today can't be designed to take advantage of the sun and other natural occurrences.

Garbage Warrior gives a good look into the process: http://www.youtube.com/watch?v=b1cUa4yWQp4&feature=player_embedded#at=11

Regards.

I opened this thread this morning and left it on my desktop so i could get to it before my big trip today.

Awesome stuff!

Unfortunately, I have to go and am out of time.  I'll try to get to this during my trip!

"In terms of "convincing others", one of the larger pieces of the puzzle in my humble opinion is getting alternative designs through the permitting process so these places can be built in populated areas that will receive attention by the masses."

Amen!

We can't get the word out fast enough.

I built a 30'x70' shop behind my house.  Pretty straightforward double wall construction to yield foot thick walls, blown full with cellulose, full vapor barrier, full house wrap.  Really, nothing exotic at all.  Late 70's to early 80's "technology".  Fully insulated 6" slab, with 4" of the dreaded styrofoam.

Since my building inspector couldn't find "this method" in "his" code book, it took enormous wrangling to get it done, and it set me back more than a year and a fair pile of money.  Bob would have had an aneurysm if I had wanted anything remotely alternative like straw bale, cob, wafati, umbrella house, etc.

We have to have options for people who live in suburbs with code dictators.  As a percentage, we can't relocate a huge percentage of the north american populace out to places that don't have or enforce code.

Conceptually, building code can be prescriptive (this is how you HAVE to do it, so stop asking about all this weird crap!), or it can be performance descriptive (this is the desired outcome we need in terms of thermal performance, show me how you're going to achieve that.)

Most codes, and most inspectors are prescriptive, not descriptive.  My current code guy is an ass clown, my code guy in Castleton Ontario Canada was awesome.


Please carry on,

troy

This is kinda cool too, although I am not sure of the advantages, if any, compared to a wofati.

http://www.instructables.com/id/How-to-Build-an-Earthbag-Dome/

To further elaborate, I have added to my last post.
Thanks.

Re my comment on "body of information."

You are right about the wealth of information available on the internet, but I find that there is much "noise" and little real substance.  I would like to see a "wikidetails" site.  Years ago, I coauthored a back page column in the AIA magazine called the NEAT File (No Excuses After This), which started in our office as a place to store details (pre-computer days of course).

TofiKrol wrote:
Re my comment on "body of information."

You are right about the wealth of information available on the internet, but I find that there is much "noise" and little real substance.  I would like to see a "wikidetails" site.  Years ago, I coauthored a back page column in the AIA magazine called the NEAT File (No Excuses After This), which started in our office as a place to store details (pre-computer days of course).

Yeah, it would be nice if there was a single source of details on the Internet. Alternative construction is so varied though, and unlike standard building materials, there are no "standards" with natural materials. Additionally, the alternative/natural building arena is still very new and experimental, relatively speaking that is. An Internet based interactive Architectural Graphic Standards of sorts for alternative/natural building would be a big undertaking.

While not perfect or easy, there is currently plenty of drawn details and related info in various books and the Net to arm one with enough info to run with and persuade many building officials to let them build. It can be a lot of work compiling the literature in a presentable form but it is doable. Also, depending on the locale and proposed method of construction, some officials will want the plans stamped by a licensed engineer.

There are going to be a lot of dogmatic officials that will flat out say "no way" but there's only one way to find out; get educated, compile your info and put on a smile.

another idea I ran across looking at some ideas was Insulated Earthbag/Geotextile Basement Walls. The fun in it is it has not been tried but should work . Looks promising. I always like combining as many ideas into as simple of a way as possible.

http://www.motherearthnews.com/insulated-earthbag/geotextile-basement-walls.aspx

--

Here is a link to appropedia's wofati page. The page also has links to other related topics like compressed earth and living roofs. http://www.appropedia.org/Wofati_eco_building

My favorite line from Paul's article is
"..to flush that idea like the stinky turd it is"
He's talking about the conventional house roof shape. I laughed hard.

BTW, folks reading this,  Paul's WOFATI building design method described in his article is some of the most up to date and logical approach to this kind of structure I have seen anywhere.  Nice one, Paul! I am going to reference this document in my workshops.

I've studied PAHS a lot, experimented a little, and can't say enough good stuff about the book by John Hait. 

Another important note is that using PAHS isn't restricted to just earth-sheltered houses.  Anyone heard of Solviva, and Anna Edy?  I'm sure you have!  Great great stuff to build on. http://www.solviva.com/index.htm

Also, I would like to say that I am actively looking for more opportunities to assist people with PAHS designs.  And, I will be teaching this summer with Earthen Hand Natural Building using the PAHS techniques as well as many other innovative methods.  Straw-clay, Earthbag, Meshbag(hyperadobe, Cob, Dome, Vaults, and so on.

Cheers,

Let me suggest considering cement with vermiculite for the roof.  It is vastly lighter, and a few inches  has the insulation value of 20 inches of cement.

I'm building a Wofati/PAHS type house using hyperadobe, pond liner, and modern amenities in Sequim Washington this summer!  Come participate in our workshops on this building if you like.  [Two 4-day events, end of july and end of aug, see www.earthenhand.com/workshops.html ] Earthbag building (hyperadobe) will be the main topic of these events, and not PAHS, but we will discuss about the later.

My main questions about the design so far is:  Will the water table moisture under the house be an issue for my PAHS?  I dug some 5-6 foot holes by the site and some were wetter than others down at the bottom.  None were sopping, but had moisture like a dry cob would.  Is this going to negate my underground umbrella?

I'm not even going to talk about french drains.  Put that in a different thread please, guys.

Wet soil behaves much differently than dry soil in terms of thermodynamics.  But it's pretty tricky to define wet, vs damp, vs dry.

So...maybe.

If you can significantly lower the water table by using trenches/gravel/perforated drainage pipe, all driven by gravity, that would be a big plus.

troy