Questions about straw bale foundations, and exterior finish

Hello all!

I am in the process of buying a plot of land, and intend to build what I am calling an "Earthship inspired" Passive solar straw bale house. I know that there is another thread that has covered another persons take on that same idea, but many of the points raised in that discussion are things that I have already taken into consideration, and believe I can remedy.

Where I am building, the code is really non existent, so I am going to take full advantage of this wherever possible, so long as it does not sacrifice structural integrity. The location is in the missouri Ozarks, or near enough to have the same climate, anyway.

The following areas are ones that I am seeking guidance on, but I will also be giving details on how I wish to build my home. If you notice anything that you think I should be concerned about, but seem to be oblivious of, please feel free to point it out. I welcome any and all criticism and advice on my build. Thanks in advance.

The basic design I have in mind, is a 20x60x10 building, with three cob walls, and the fourth, facing south will be where I pick up the passive solar, and attack my 15' deep attached greenhouse. The greenhouse will be attached completely to this wall, and will not contact the SB. The glazing for the greenhouse will be thick, polycarbonate panels. I know the panels are not permanent but I want to go with them for the first several years at least. They diffuse light, and I'm hoping that will help negate over heating. Other steps that will be taken to avoid overheating will include large radiant barrier drapes inside the home, and a vertical, rather than slanted greenhouse wall.

For the roof I will be using a roof only pole kit, that I will insulate and vent. The floors will be insulated rammed earth. The interior will be warm earth colors to help capture more radiant heat. I will also have interior fireplaces, though not in contact with the SB walls.




The Foundation.

I intend to make my foundation with a gravel trench, with one layer of used tires above them also filed with gravel, as the foundation and a way to lift the straw bales up out of the elements. I will be plastering the bottom of the bales as I set the first run, and then build up. I will also be incorporating multiple french drains to aid in shedding water, and the soil I am building on is greater than 60" deep, and has excellent drainage. Will this be enough, should I go two layers high on the tires to further elevate my walls?

Exterior Finish.

I am currently trying to price out the use of lime plaster, both interior and exterior. I know that a permeable finish is needed for SB homes to have any kind of longevity, and this is why I am going with the lime plaster, though knowing how much I will need is proving to be a challenge to learn. What I am considering, that seems to be highly advised against, is sealing the exterior plaster. I know that sealing SB is a bad idea, as it will be unable to exchange moisture. My thought is, the entire interior will be unsealed lime plaster, and will lead to a well ventilated, highly insulated roof. Will this be enough to keep the SB in good condition? The reason I consider it, is the amount of driving rain we get in my area will make keeping an unsealed lime exterior very difficult to work with, and the high humidity in the summers will also prove challenging.



Goals.

Budget

I have a set budget goal for the main part of the house, that so far I am well within, though I am having trouble determining the cost of lime plastering 2000 sq/ft. This does not include the cost of the greenhouse, as that will be a later addition. I make very little money, and would like to own my own home, with my income, within two years. The plans that I have come up with will be very cheap, and something I can do in stages, albeit some larger than others.

Longevity

I hope to raise a family in this home, and I would like for it to last at the very least, the rest of my life, if not multiple generations. I understand that this will require upkeep, but what home doesn't.

Performance

I intend for this home to be affordable to cool during the summer, and ideally not require much supplemental heating in the winter. Our temperatures vary wildly, with colds as low as -20 some years, and triple digit heatwaves that can last weeks. With the high thermal mass, that will be painted white on the exterior, and will have a very well insulated roof, with radiant a radiant barrier, I hope to be able to manage the warm summer weather with minimal air conditioning.


Thank you for reading, if there is some detail I left out, that needs included for you to help me make a decision, just ask and I will be happy to explain.

Thanks!

Dan

I lived in a strawbale house about 100 miles north of the Ozarks. It was the dampest moldiest place I ever lived. Uugh! Probably designed wrong, knowing who was involved.

My greenhouse has polycarbonate panels. They definitely don't keep it from overheating. Opening windows and doors is my method of dealing with excess heat. Auto-openers are really clever.

Hi Joseph,

A few quick comments. Sealing the outside of your SB is definitely a baaaad idea. Essentially you are covering your SB with a sheet of plastic. When the moisture from the inside hits the moisture barrier n the oustide, it will condense which will soak your bales and then say bye bye to SB house. Or something like that. Let me reassure you! Lime render on SB is kick butt especially on exteriors. SB structures that have been rendered with lime have lasted ups to 100 years! Here is a thread where J Whitecloud gives some good examples of Lime rendered SB structures. Also here is another thread I had started discussing using tires as a foundation for straw bale. Apparently they have already been doing this in UK. Someone on the thread posted a link you can go to giving detailed plans for that type of thing.

Here is a consumption chart from St. Astier, one of the best Natural Hydraulic Lime distributors in the US. That should help get you on track for home much lime you need. Check out Chris Magwood and what he is doing making his own NHL with domestic pozzolans. You could also consider doing earthen plaster on your walls because you had mentioned wanting earth tones? I guess lime white could count as an earth tone but just wanted to let you know that you could lime the exterior and earthen the interior. Cheers Phil

Thanks! I will check out those links, and learn all that I can. Depending on the soil type in the area, I had intended to do an earth/cob plaster for the interior to match the floors, but I wasn't entirely sure if it would be good enough at the depths I would be going. I will definetly check out white clouds discussion, that guy really seems to know his stuff.

Hi Dan,

First...say Howdy...to that area, as this is where my family is from... You are lucky, as I think it is one very special place!

I hope you do enjoy and gain some practical use of the stuff I have share here at Permies, thanks for the complement...

I am not sure if you use Sketchup of just draw on paper, yet a few photos of the building site and some elicitation and plane few diaphragms or CAD models of the project would help emmensily in understanding things.

You asked about things that jumped out...

>>>

The basic design I have in mind, is a 20x60x10 building,

I am a real hound about aesthetics, the "golden mean," traditional forms and their logic...etc. Without seeing a model and the building site I can't really comment, yet the dimensions above seem awkward and a bit out of balance (too rectilinear.) This described shape can work and look good if balanced in the landscape...I do look forward to seeing more images...

...I pick up the passive solar, and attack my 15' deep attached greenhouse. The greenhouse will be attached completely to this wall, and will not contact the SB....

This could be debated as a subjective view...yet 40 years of study and observation demonstrates that "attached greenhouses" as described here are a very challenge element to the architecture. I am not a big proponent of the entire "passive solar" thing anyway, as it is implemented today. I do love "proximal" greenhouses, solarium/atrium structures that are independent of the living space but still close enough to take heat from and gain access to comfortably.

Battling over heating, high humidity and other moisture related challenges are not worth the effort for the gains received. Let Greenhouse related architecture be what they are and let your house be what it needs to be...then create comfortable and aesthetically pleasing "air lock" or breeze way between the to completely different architectural forms

For the roof I will be using a roof only pole kit, that I will insulate and vent. The floors will be insulated rammed earth. The interior will be warm earth colors to help capture more radiant heat. I will also have interior fireplaces, though not in contact with the SB walls.

Can't comment much without seeing model...I do not support or recommend "structural" SB architecture to anyone that has not been a professional "traditions/natural" builder for at least 10 years and has several "good and well preforming" SB projects to reference from. Emulating other's design in this form and style of architecture is not worth the risk of getting thing incorrect...in my view. Do some get this right? Absolutely they do...In my experience...this is the exception, not the rule. That's my 2¢ on that subject...

...gravel trench, with one layer of used tires above them also filed with gravel...Will this be enough, should I go two layers high on the tires to further elevate my walls?

Need photos of building site and model plans even if just a sketch on paper and a photo of that...

I recommend reading the entire post: Raised Earth Foundations

Exterior Finish...lime plaster, though knowing how much I will need is proving to be a challenge...

Quick note on limes...globally and traditionally "hydraulic" limes (NHL) are the acceptation and actually very uncommon. It hasn't been till since the about 1880's that these harder limes have come into vogue and that also is highly regionally specific. Sense the SB movement really started taking hold in the late 80's did we see a recergence of NHL. If they are avalable and affordable...by all means use them, especially for exterior work. However, don't worry at all if you can't afford or get them. A simple hot lime mix will work fine, and lime washed clay/cobb renders have lasted centuries on well designed structures.

...What I am considering, that seems to be highly advised against, is sealing the exterior plaster...

To quote Philip Nafziger, "...Sealing the outside of your SB is definitely a baaaad idea..."

What I would add...no matter what one may "think," theorized, or have been told.....ON'T EVEN THINK ABOUT IT!... It does not work with wood, does't work with brick and stone, it just doesn't work period for any length of time...especially on traditional and natural buildings. The interstitial damage is usually so significant that is is equated with a full conflagration of the structure...That is how damaging it is. There is some evidence for treatments, from only very specific manufactures, with "siloxanes," yet this is neither well proven, documented nor a complete conclusion of being a safe material, nor worth the risk or cost. These types of natural buildings have lasted hundreds and in some cases thousands of years without any modern plastic, paints, vapor barriers, sealers or other noxious augmentations...

will lead to a well ventilated, highly insulated roof. Will this be enough to keep the SB in good condition? The reason I consider it, is the amount of driving rain we get in my area will make keeping an unsealed lime exterior very difficult to work with, and the high humidity in the summers will also prove challenging.

No it won't (wouldn't) be enough. Build the structure with the correct overhangs, rain screen/cold roof design and natural convective flows and it will not only function but flourish and be comfortable year round...

I have a set budget goal for the main part of the house, that so far I am well within, though I am having trouble determining the cost of lime plastering 2000 sq/ft.

Not including your labor...it is unlikely to get the plastering/rendering achieve for less than $3/ft2 (national average...with a $1.75 being the rock bottom pricing matrix and can go as high as $10/ft2)

Posting an actual design schematic and budget will solicit more accurate feedback from folks...


Longevity...I hope to raise a family in this home, and I would like for it to last at the very least, the rest of my life, if not multiple generations. I understand that this will require upkeep, but what home doesn't.

If designed and built correctly most any of the suggested natural builds in the traditional/natural building venue could effectively last well over 1000 years if not destroyed by some other exterior catastrophic event; most with very little costly maintenance.

Performance will simply depend of design and facilitation of build...

Regards,

j

Hi Dan,

This sounds like a great project!

I would probably go with all cob in your climate. I have lived in an adobe house here in northern Utah for 20 years and I couldn't recommend earthen walls more highly.

Lime plaster is an excellent choice for interior and exterior coatings, but clay makes a great interior plaster and if sourced locally can be free. Lime plaster can be made from regular type s from the big box and a good sharp sand. St Astier is nice, but I don't use plaster shipped from France($$$). Anything with free aluminum and silica will produce a nice pozzolanic effect, which can make the plaster stronger and faster setting, but this comes at the cost of plasticity and workability. That's why NHL's have the numbers beside them to indicate where they fall on the scale of hardness/plasticity, 5 being the hardest and least plastic.

People tend to think this is some sort of magic, but it is a simple product that people have been using for at least 10,000 years.

Recently, I have switched to a locally made pozzolan lime plasterhttp://limestrongfinish.com, but before that, I made my own from type s lime, wood ash, quartz sand, hair(horse tails and manes) and marble powder for the polish coat. This will cost you about $1000 for a 2000 sq ft home plastered inside and out(around 6000 lbs of plaster).

Lime is not a "one and done" kind of product; it takes finesse and timing to properly install, but my 120 year old adobe still has the original lime plaster and that's not even old for this product.

I would also recommend a random rubble stone stem wall mortared with lime/sand on the rubble trench/tire founds.

Well, that's all of my opinions right now.

All Blessings,
Bill

Thanks for the replies! I really love this part of the world, and I totally agree that it is something special. Sadly I don't live in the actual Ozarks anymore, but I'm only thirty minutes away so that is nice, The climate is still exactly the same.

I will definitely read the foundation thread, and I have completely abandoned the notion of sealing. I will just use a straight lime plaster, and as this will be a labor of love, I will be taking my time to get each point just right.

I will try to get a sketch up this weekend, and an architect from Canada actually Mosseaged me and offered to draw something up just so he can get some practice with the concept, just another reason why I love this place so much.

In the meantime, the pole building roof is pretty straight forward, just poles concreted into the ground, with an open roof attached to the top, the kind of building that farmers use to store hay to keep it dry. I have some incredibly knowledgeable friends, who are very well accustomed to traditional construction, who are helping me plan that part of the project, as well as lending ideas and knowledge in many other aspects of the build. And since sealing the outside is an absolute deal breaker, I have come to the conclusion that overkill is highly under rated. So now, I intend to have the pole roof made to be 25x70, but I will keep the interior dimensions the same. This way I can have the rest of the roof cover five feet on the three sides that have the strawbale walls (non load baring), and use the extra space as a wrap around porch. It shouldn't cost that much extra, will keep the elements off, especially if i screen it, and will add a nice feature.

This means that the SB walls will not bare any load, and will be well protected from the environment. I'm also hoping that all that summer shade will help keep the building nice and cool.

As far as labor and budget goes, it will be 100% sweat equity. I have friends that regularly employ my labor at the cost of lunch and gatorade, and will be working for the same. As far as the budget goes, I want to keep it under 10k for just the structure, not including the plumbing electric appliances etc. I know this might seem far fetched, but thus far with the materials I have priced at store cost, I am well within the limit. I am also lucky enough to have several local spots that sell building materials for dirt cheap prices, so I will figure for the most expensive, and spend time hunting down deals to get this done the best that I can, without sacrificing quality.

And Jay, since you are well aware of the climate I am in, if I build this place correctly, well ventilated highly insulated attic, insulated earthen floor, keeping the interior shielded from the summer sun, what do you think my chances are of not having to have an air conditioner? I am planning for it to not be possible at all, but If I am wrong, I am EXTREMELY interested in hearing more.

I get your concerns about the attached greenhouse, and have read them on other posts as well. But I am so taken with the idea of growing tropical fruits in my home, basically in a very large terrarium, that I am married to the idea. That being said, it is going to really be more like an enclosed carport with vertical glass walls, and possibly a sloped polycarbonate roof that attaches to the front of the house. I have been learning from another post I made in the the passive solar forum that they supposedly make a type of polycarb that reflects most of the heat, but still lets in a lot of the light. I am not married to this concept yet, I still have a lot of research to do on it, but that would totally help with summer heat. And as far as winter overheating goes, I am confident that I can manage it. Yes at first raising and lowering shades and what not on that big of a wall is going to be a pain, but will be doable. After a year or two though, I am going to move to nearly full automation of both the house, and the micro farm I intend to have on the .71 acres. Sensors to measure floor and air temperature, that will raise or lower shades automatically, moisture sensors in the raised beds to turn on the watering systems for just the right amount of time, etc.


The land is pretty bare, I think maybe one or two trees, and has a slight slope to the north. Not normally ideal for a passive solar home, but the winter sun will still be perfectly in range for the passive solar concept. I am most likely going to be putting in a swale in front of the house, and between that and the building, a french drain, to keep the water well away from the house.

Bill, that cost for plaster is right up my alley! Before I knew the difference, I had priced out quickcrete stucco and it was about twice that, so I am super stoked that the proper materials for the project I am undertaking is even more affordable. S type line is easy to come buy, but I am told that we can get agricultural lime for a great price. I just learned about this today, so I haven't had the time to research it yet as a building material.

I had originally wanted to build with all cob, and the soil in Missouri is renowned for its high clay content. At least we think it is . The problem though is I would most likely have to dig it all out at the location, and for what I want, that would be a pretty big hole. Not to mention the labor involved would be incredibly time consuming for two or three people. Another concern that I have about it is that I have read about other people who have build cob homes here in Missouri, and found them unlivable during the winters. SB will provide extremely good insulation, and between it and the like plaster it should have the thermal mass department covered. I have been considering from the get go using the soil that I dig from the foundation to be used in the interior walls, but I am planning for the worst, in the event that it wont be suitable for making the interior. If it is, and will work, I might make my entire south wall out of cob, just to keep things easy and cheap.

Sorry im kind of bouncing all over the place, its well past my bedtime, and I worked a 12 last night, and am looking at another one in a few hours. Well worth it for what I'm working towards, however. I'm super pumped right now because I just signed the contract, and made my first payment for the land! $500 a month, for four months. The guy isn't even charging interest. In my county, that is a hell of a deal, especially since it will have city utilities, but the "city" is tiny and rural enough, that pretty much anything goes. When I scouted this place out a few months ago, the neighbors have everything from chicken, to sheep, to ponies in their yards, and if half of those houses would pass any kind of code, I would be suprised. Getting ahold of the city to ask about any permits or codes is pretty tough, as they never seem to be open when I call, but ofcourse, I will be double checking before I do any of this, though I am pretty confident that anything goes. I even confirmed with the county commissioner that they have no jurisdiction where I want to build, and its entirely up to the city.

I hope I covered everything well enough, without having any drawings. I will try to get something put up this weekend to give a better example of what I'm describing here.

Thanks again for the responses, and guidance everyone!

Dan

Hi Dan,

Per your last post...

...I intend to have the pole roof made to be 25x70, but I will keep the interior dimensions the same. This way I can have the rest of the roof cover five feet on the three sides...

I like the "pole frame" concept...much better.

20x60 (presuming this is finished outside dimensions?) and then roof 25x70...?? This is kinda of a "trailer size" and not even a double wide. Again I can see it fitting a tight ledge on a steep slop or cliff, or being a size needed to accommodate a given foot print (e.g. building on a floating barge, small lot with odd shape, etc.) other wise this is not anywhere within the "golden section," unless being designed as separate structures working as one. Is the .71 acres lot size the reason for the very long and narrow foot print?

I am not seeing how we get five foot over hangs on three side? That makes for a 2.5 foot overhangs on four sides, or zero overhang on two sides and five foot overhangs on two sides...?? What am I missing? I would also suggest from the perspective of overhangs, 2.5 feet is not even close to overkill and as a porch roof, as suggested 5 feet is actually very small and only if the porch (walk way) is 3 feet wide, as the minimum overhang for most "natural builds" is 2 feet.

...10k for just the structure...might seem far fetched, but thus far with the materials...

Hmmm...I wouldn't call it far fetch per se, but I am uncertain of the accuracy? This is to cover all the insulation/SB, the lime, the wood elements, tooling, windows, roofing, etc ?? If you have typed up a cost breakdown/gantt chart it would help folk to see it, either for guidance to you or (if accurate) good information for them to have...

...what do you think my chances are of not having to have an air conditioner?

Personal ambient comfort zones is really subjective, yet on average, if a natural build is design well, augmented cooling in the summer should never be a necessity accept in extremely hot weather, and even then sometime it isn't an issue either...All design, build, and material dependent...

...But I am so taken with the idea of growing tropical fruits in my home, basically in a very large terrarium, that I am married to the idea...

"Thinking" something sounds good, or falling in love with the romance of a notion/concept is often how these things happen......

Be it modern designs with too large of windows to no roof overhangs, etc. It may look good to someone, or seem like a grand plan (with future possible changes and upgrades), or just be a "I like it," matter. I will leave you to your concepts, and "wants" as these are individual subjective goals that one such as I shouldn't be critical of. However, it was asked about possible issues with this concept and if the structure is challenged in any way. I can predict with some certainty (~90%) if the current design concept is followed as described it will have moderate to sever moisture issues, or become too hot...(among several other chronic challenges with such designs)...

Even a well heeled project budget, under the supervision and direction of an experienced design/builder, who is processing a committed assiduity, and comprehension to these many modalities of means, methods and material employment as it applies to natural buildings would be hard pressed to achieve this "growing fruit" level of a greenhouse, while being well incorporated and integrally connected to the overall living space. Not without heavy incorporation of technological devices and super high end ventilation and monitoring systems. I don't see this as achievable within the current budget or skill set of a DIYer...I would pleased to be wrong on this...

S type line is easy to come buy, but I am told that we can get agricultural lime for a great price.

Make test panels, and understand very well what is being done...lime can be very challenging if just walking in cold and thinking it can be done easy. Ag lime is not for building...

As for the cobb vs SB...without designs I can't say. As for labor SB usually is less labor compared to traditional cobb. I would suggest "straw or wood ship clay slip," over SB, or cobb in most applications.

Regards,

j

"I am not seeing how we get five foot over hangs on three side? That makes for a 2.5 foot overhangs on four sides, or zero overhang on two sides and five foot overhangs on two sides...?? What am I missing? I would also suggest from the perspective of overhangs, 2.5 feet is not even close to overkill and as a porch roof, as suggested 5 feet is actually very small and only if the porch (walk way) is 3 feet wide, as the minimum overhang for most "natural builds" is 2 feet."

The south facing wall will not be made of SB, but most likely cob, and will run about right to the end of the roof, like a normal house would. This will be capable of acting alone, but will be the side with the attached greenhouse. I hope to make you a believer in the attached greenhouse, so long as, like SB construction, it's done right. The greenhouse area will also have the grey water cells for planting, as well as other growing areas, and most likely an outdoor table set up.

This leaves five feet across the entire back wall. As the interior walls will stop at 60 feet, or there abouts, this will leave five feet on each end. Now that you mention it, that would be a pretty narrow porch, but that would be something to come later. This is just an easy way for me to get plenty of overhang, to help protect my walls from the elements, and provide extra shading. The walls will also be white, so that will help them not pick up a lot of heat during the summer.

"Hmmm...I wouldn't call it far fetch per se, but I am uncertain of the accuracy? This is to cover all the insulation/SB, the lime, the wood elements, tooling, windows, roofing, etc ?? If you have typed up a cost breakdown/gantt chart it would help folk to see it, either for guidance to you or (if accurate) good information for them to have... "

Once I get the preliminary price list completed, I will post it up. I wont be surprised if I end up going over, but with luck, and help from all of the discount building supply stores in my area, I also wont be surprised if I go under budget.

"Personal ambient comfort zones is really subjective, yet on average, if a natural build is design well, augmented cooling in the summer should never be a necessity accept in extremely hot weather, and even then sometime it isn't an issue either...All design, build, and material dependent..."

We definitely get some extreme hot weather. Once I have more key concepts down, and know exactly how I'm going to build this and that, I am going to do some research on subterranean cooling tubes. But if I cant get any good info on whether or not that would work, I will just go with a regular AC unit, and run the ducts where I can. If it comes to that, since the roof will be so well insulated, and will use a radiant barrier, I'm betting I can get away with running it through the attic. I'm not really focused on that right now, but I know I can make it work if it comes down to it.

"Be it modern designs with too large of windows to no roof overhangs, etc. It may look good to someone, or seem like a grand plan (with future possible changes and upgrades), or just be a "I like it," matter. I will leave you to your concepts, and "wants" as these are individual subjective goals that one such as I shouldn't be critical of. However, it was asked about possible issues with this concept and if the structure is challenged in any way. I can predict with some certainty (~90%) if the current design concept is followed as described it will have moderate to sever moisture issues, or become too hot...(among several other chronic challenges with such designs)...

Even a well heeled project budget, under the supervision and direction of an experienced design/builder, who is processing a committed assiduity, and comprehension to these many modalities of means, methods and material employment as it applies to natural buildings would be hard pressed to achieve this "growing fruit" level of a greenhouse, while being well incorporated and integrally connected to the overall living space. Not without heavy incorporation of technological devices and super high end ventilation and monitoring systems. I don't see this as achievable within the current budget or skill set of a DIYer...I would pleased to be wrong on this..."

Don't get me wrong, I understand the concerns that you have, and am certain that your hesitation to follow this through is based on a wealth of knowledge and experience. For this aspect of the build, I will be following very closely the methods and procedures already undertaken when building traditional Earthships. There are Earthships in my climate, my area, and even hotter and more humid ones as well. Earthships, for all of their flaws from earlier designs, have come a very long way. Though I'm not incorporating the tires, the berm, or the concrete and can/bottle walls and other concepts, I will be following the successful practices that make well made Earthships something very remarkable. And these are all done without elaborate systems to shade or vent, and that is how I will do this in the beginning. The automated stuff will come later as a project for me to undertake, partly for convenience, and partly for "funzies".

And as far as growing fruit and what not, that is actually very easy to do in any greenhouse. One of the biggest gimmicks in each video released by Earthship Biotecture shows bananas being picked and eaten when there is a foot of snow outside. If that means that I have to have a rocket mass heater during the winter for the cloudy times, I'm totally cool with that. If people can grow mandarin oranges in their windows, and have plastic greenhouses hosting small citrus orchards, in Canada of all places, I'm sure of the feasibility of this and look forward to the free fruit and nice smells. Hand pollinating with an electric toothbrush will undoubtedly become a pain in the but though, I'm sure.

"Make test panels, and understand very well what is being done...lime can be very challenging if just walking in cold and thinking it can be done easy. Ag lime is not for building...

As for the cobb vs SB...without designs I can't say. As for labor SB usually is less labor compared to traditional cobb. I would suggest "straw or wood ship clay slip," over SB, or cobb in most applications."

Thanks for the heads up about the AG lime. Once I got a chance to research it I saw some people giving it a go, but not showing many long term results. And these where mostly for aesthetic interior spaces, and not so much for any other function that looking nice in a regular, modern home. I will definitely be testing as much as a can before the actual build commences, because not only am I going to be doing this myself, I'm going to have to show others how to do it the way it needs to be done, when it's time to call in the volunteers.

I will be using cob if the soil I get is right, but most likely for the interior, as I'm doubting I will have enough to both inside and out. But if I can, or if I can find a good source of local soil that I can process into useable cob, I will totally go with cob for the whole thing. It will most likely save me money, work really well, and I just like cob.

I appreciate all of the input, more is always welcome, and I will get some sort of crude sketch up this weekend.

Thanks again everyone!

Hey Dan,

I do want you to understand very well (which is hard without "face to face," conversation that I really enjoy reading such enthusiasm as you share for your plan project!

I promise to always give my very best direct answers (as I know and understand the question) and anytime I feel that the information has an overly subjective perspective, I will let that be known.

I want only success for any project shared, and have tried very hard to never share information that is not solicited first (unless I see a real risk to like/property) so if someone is just “sharing ideas, plans, concepts” without actually asking a “question,”...I have really made an exerted effort… ...to keep my fingers still and not respond...As such if anyone does ask a question..I will always do my best to give the best response I know, or have experienced….

Now to the current queries/comments…

The south facing wall will not be made of SB, but most likely cob, and will run about right to the end of the roof, like a normal house would. This will be capable of acting alone, but will be the side with the attached greenhouse.

I wish, for your sake, I could get behind the attached and full frontal greenhouse as you have described it thus far. Alas, I am afraid many years (and many careers) worth of experiences won’t allow me to “believe in” such designs being good practice compared to others design modalities.

I will try to validate a little more to garner additional trust in my perspective of this “attached greenhouse concept.” I understand that a great many push strongly for and about the exact concept you are trying to achieve, and that there are many photos and descriptions of all the positives that these bring. Most of this information comes from those selling it, and/or living in them (both of which present a rather very subjective perspective.)

I am much more than just a “natural builder.” I have studied, examined, designed and built (or been part of building) so many related “solar gaining structures” I have lost the number and account of them all. I have been part of, in some capacity, zoological artificial habitats, enclosures, vivarium-aquarium, aviary, large mammal enclosures, greenhouses, solarium, atrium, etc. This “cross over” knowledge and experience has given me an insight into these structures that the average professional design/builder doesn’t have, and seldom (not never ) DIYers.

If anyone has taken the time to read just a little of what I write, they can glean that I am a strongly pragmatic facilitator of architecture whenever I can be. I love creativity but not at the cost of “reinventing” something that already works well on its own the way it is (aka if ain't broke...don't mess with it), or trying to “make something work.” “Making things work” is a huge gift of human creativity...a big positive! Yet, with positives, often come imbalances in perspective that leads us down the path of trying to “make” anything we think of “work”...There is the paradox of pros, and cons there.

If a client requested I design and build a large atrium-solarium attached to the front of their new natural home to be functional in all four seasons and not have any (or very few) of the ensuing issues that come with them...I can do that, and probably pretty well. This design feature in any architecture will neither be inexpensive nor lack much more time to design, test and build...and I would add...probably a lot of moving parts and technology that a natural doesn't have to have to usually function very well.

Now, I can also achieve the same “affect” in the architecture with a separate (but connected) greenhouse type structure. The cost will be, at minimum, less than the other (usually), and often has more features and benefits than the other while being more “user friendly.” Just moving your concept to the side of the building with a well insulated separating wall would be a vast improvement over a full frontal concept. Moving it a bit farther (perhaps 10 to 12 feet??) with a breeze way, lanai/veranda or related type connector would be even better...

On overhangs...to be clear...has a bare-bones minimum of 2 feet and a 4 foot to 6 foot overhang much better, all design dependent of course. I should stress again, presuming you are moving forward with the design as described with a frontal "solar gain area," that “greenhouse” designs of almost all types found in “solar gaining architecture” have a much more restricted viable lifespan than any domestic/agronomic architecture. Only the very well designed and built last more than 150 years, with most lasting less than 10 to 20 at most. This is but one more very large reason not to have them be so integrally incorporated in the primary domestic architecture, as they well (not if) have to be “undone” within half a generation at minimum in most designs with over 80% replaced and/or heavily repaired in some fashion. This is an unnecessary costly event that can and should be avoided. The few exceptions to this is a design that allows expedient and easy facilitation of seasonal removal. This “transient” form of attached greenhouse is never as well sealed during colder weather as a structure built to be as permanent as possible, and often has many other challenges.

...I am going to do some research on subterranean cooling tubes. But if I cant get any good info on whether or not that would work, I will just go with a regular AC unit, and run the ducts where I can. If it comes to that, since the roof will be so well insulated, and will use a radiant barrier, I'm betting I can get away with running it through the attic. I'm not really focused on that right now, but I know I can make it work if it comes down to it...

I will try to cover a few points on the above comments.

First, as said before, I always make every effort myself to not waste time, effort and money in trying to have the…”make it work,” outcome of planning and design. Either a concept and design is well vetted, functional and logical...or it is not. Reinventing the wheel might be fun and even worthwhile pursuit, but not when we are in the realm of try to go about “living.” The best metaphor I give students on this comes from my other area of enjoyment...Indigenous and wilderness life skills. We do not “test” how long we can go without food and water when we are actually living without access to “food and water.” “Testing” is for when we have the luxury of doing it safely…not when under duress or governance of time and money (food and water.)

Radiant barriers as they are being advertised, and marketed today are only “concept” in nature and most are more “snake oil” than practical elements of design. Of all the “aluminized” bubble wrap and related types, none will last a fraction of the time of even the average structure will last. They also are, for all practical matters, nothing more than thick “plastic warps” that are absolutely not permeable in nature. They not only are blocking breathability but also form a “condensing surface.” Leave “radiant barrier” concepts to traditional modalities like the color white and related methods. I would also note that if you go to the hottest places in the world, many of the folks there dress in black, which seems counter intuitive, but until one lives for any length of time in and with “desert people,” it is hard to understand many of the “hot climate” concepts of living and building.

Earth tubes is a “reinvention” of old concepts. Some (actually very few) seem to work, while others are already having issues with mold, and moisture related issues. I am intrigued by them, but the few that “seem to work” are all the very large systems that are well below grade (3 feet minimum) and large enough to crawl through. This not only facilitates inspection, but the very important aspects of proper maintenance when needed. I do hope to experiment myself with one of these builds but it cannot be the only “cooling” element for the architecture to depend on.

...I will be following very closely the methods and procedures already undertaken when building traditional Earth-ships...I'm sure of the feasibility of this and look forward to the free fruit and nice smells...

When I read “following” when reference to something like “earth-ships” or other rather modern reinterpretations of traditional design, I become very concerned and weary. Architecture is not like cooking...it is more like chemistry. You have to get the recipe perfect or what was supposed to be a fancy souffle turns out to be a rather icky sweet omelet thingy... …I stress for DIYers to always go with “tried and true” vernacular designs that works well "as is" for a specific region/biome over “trying to make work” something they want to “try and copy." When an actual specific model concept drawing is offered we can get into a much better critique of the project.

As for “feasibility,” that goes hand in hand with “making it work,” and I have said enough about the ergonomics, economics and logic of this…

I appreciate all of the input, more is always welcome, and I will get some sort of crude sketch up this weekend

.

I look forward to your drawings…

Regards,

j

I do want you to understand very well (which is hard without "face to face," conversation that I really enjoy reading such enthusiasm as you share for your plan project!

I promise to always give my very best direct answers (as I know and understand the question) and anytime I feel that the information has an overly subjective perspective, I will let that be known.

I want only success for any project shared, and have tried very hard to never share information that is not solicited first (unless I see a real risk to like/property) so if someone is just “sharing ideas, plans, concepts” without actually asking a “question,”...I have really made an exerted effort… ...to keep my fingers still and not respond...As such if anyone does ask a question..I will always do my best to give the best response I know, or have experienced….

Once again, I really appreciate the responses and advice given. My favorite thing about permies, is that it is full of people that share some of my passions, and I love the fact that your are as excited to teach, as I am to learn. As far as waiting for something to be solicited, by all means, don't wait. You don't need to hold off and wait for me to mention this or that, if you have input, please don't hesitate to tell me what you have in mind. The attached greenhouse part, I understand your reservations, and am going to be very mindful of how all that goes down. If it ends up being a problem, it wont be hard at all for me to just take it down, and move it somewhere else. Then I could take the entire south wall down, as it wont be load bearing, and re do it so that I can better insulate it.

And in regards to your concern about the golden ratio, and the lay out, I will consider making adjustments, but I am a function over form kind of guy. The house will be long and shallow, to allow the passive solar effect to really take off. With all of the thermal mass in the walls and floor, I'm expecting to only have to fire up the fireplaces during the cloudier stretches during the winter. In my part of the world, the summers are usually pretty sunny.


As far as the cooling tubes, I have been looking into them the past few days, and they don't look very good at all. I knew there would be potential problems with mold and moisture, but nobody has really seemed to be able to resolve that, and I don't really like how any of it as come out. So that means that I will just be going with regular old AC, that I will be running through the attic.

The radiant barrier stuff, I know is a lot of hokum. I will be using a light colored, reflective metal for the roof, haven't decided exactly what color, but that will be a few months down the road. The barrier I am looking at is super cheap, and connects inside the attic, about 6" from the actually roof. Depending on the type of roofing I get, this probably wont even be needed, but I have seen promising results from this stuff being used. Some of it is totally crap, snake oil exactly like you mentioned. But in the attic, with a bit of an air gap between it and the roof, it supposedly will help keep down the heat. This would also be installed so as not to interfere with the ventilation, and can be easily removed if it proves worthless. But, given your advice, I will build it up without it first, and only add it later if I need to get my attic space cooler. If like you said, with a light colored roof, lots of ventilation will do what I need, then that's all the better.

You have to get the recipe perfect or what was supposed to be a fancy souffle turns out to be a rather icky sweet omelet thingy

I actually lol'ed at that. It is a perfect analogy, and I see what you are trying to point out. There are earthships in my climate that work just fine, so I know that this can be done. I guess an atrium would be a better way of putting, what I want for the front. Or maybe just think of it as a long, glass covered front porch. The front of the house will be built normally, as in with cob. And completely enclosed. The only way that air will be moved from the house to the atrium would be to open windows. I will have the low gain poly carb sheets for the top, that I will be able to open to vent the air when it's too hot, as well as the doors coming in from the sides, and some of the front, vertical windows will be able to be opened, to allow air to move.


Ok so for now, this is the best that I have, while I find the time to learn to use sketchup. This is a basic layout from a site that helps you design a home, so they can sell you home decor stuff. It is pretty rough, the windows are not the way they will actually turn out, on the house part that is, and it doesn't show the roof or specify the bale walls or anything like that. So keep in mind that the bale wall will be the north, and the two shorts. The south will of course be the one with all the windows. And the roof will basically be a separate structure, with this build underneath it. Remember I'm getting a haybarn kit, then converting that into an actual roof.

Let me know what you think, sorry it took so long to get this up.

http://www.homestyler.com/designprofile/a09ff2f4-aa78-42ed-af68-b503f65286f5

Hey Dan,

Looks like you are settling on a plan and I will only address points of observation that I haven't made before now. Overall things look good. The aesthetics may not mean much to you (form over function) but unless you plan on living there alone, or never potentially selling the place at all, then aesthetics are actually pretty important. That doesn't mean you should abandon your foot print shape at all, but be conscious of homeostasis in the design overall. The golden section and other "good design" methods should be looked at, learned and understood to the best of you ability.

But in the attic, with a bit of an air gap between it and the roof...

I am glad you will leave this to do later. I will add one more bit to this. I am having the conversation with another member as well about all manner of thing. She (Mariah) on here own, is starting to draw the same conclusions about "modern concepts" as I have thus far shared. "Radiant barrier" in the roof is a perfect one to look at as a comparative logic element.

It is claiming to be a reflective barrier, and like so many modern "concepts" sounds great in words and perhaps even in "laboratory application." I got to witness once, a demonstration of this material with some testing equipment of sorts. They took infrared, and/or some other monitoring/measuring equipment, I didn't pay attention to because....of what I saw and observed. It was actually a floor and roof demo of the product, and I, with several others noted that they kept whipping off the material. An audience observer questioned this and an actual company representative said,

"...Oh we have to whip it down, as it is vital for the product to not have anything on it to interfere with the reflective materials function. Every bit of dust, or particle mater that lands on this will degrade its efficiency in being an actual "radiant surface."

Several of us looked at each other and then someone else presented the observation that if it must stay free of dust to fully function and we are suppose to place it in an attic or floor area with an air gap, how are we suppose to keep dust off of it? These are two of the most prone places in architecture to accumulate massive amounts of dust! The product rep said that..."shouldn't be a problem," if installed properly. Someone else then asked again, what is stopping the material from getting dust on it? No answer but was given the last time. I then had address the issue with a direct query of observation. We are in a clean area working with this material and dust is getting all over it because of static charge...I can't see how in just 3 to 5 years this material would be rendered completely ineffective as a radiant barrier and only adds cost to a project. The company rep through out some statistics and "field data" that was less than 20 years old, and went on to deflect the observation with repeated info.

Bottom line, the material is great in concept and poor in real world...long term...function, just like so many more "concepts" being sold as well tested and vetted products. Good attic venting works great and even a black roof with proper design and "chimney effect" will vent better than most modern roofs. You will see all kinds of black standing seem roofs up here in Vermont. That is because we learn that on a well pitched roof these roof warm in the winter and shed snow, and in the summer heat up and cause strong convective drafting currents that pull air through the attic, thereby cooling it off naturally. All these little details of vernacular design that are so vital to the over all long term function of a structure working and...working in balance.

I will take a gander at the model tonight to give it a good critique....Well, maybe not

I am one of those people that see number and shapes in my head in a "3D" format. All along during this conversation the numbers didn't equate with the shapes described. I often find that folks have images in there head, but when it comes to "real world" application to the dimension they are restricted to (or have chosen) the two concepts (dimensions vs geometry) just do not jive at all. The model you shared is way out of proportion from the dimension shared. What may take you hours or days to learn/do I can do in my head and render in CAD withing a few minutes (in this case a cup of coffee while I watch the birds flit around in the back yard.) Below is the actual model that you have described in shape and dimension. I don't think it is quite what you envisioned, as the roof overhang won't really work well and has the lowest pitch I would recommend for such a build.

Email me and I can send a copy to you to play with. There is a lot of "rethinking" that needs to happen to make this a "buildable" plan to work from, but should get you moved much further along the process in achieving your goals.

Remember I'm getting a haybarn kit, then converting that into an actual roof.

Also, what does this mean? Are you buying a frame package from someone and then sticking straw bale and cob walls under it? Where is this coming from? What is the wood species? Who engineered the truss assembly? I have a number of questions about this one.

Regards,

j

Plan View


Isometric without roof


Isometric View

Yeah, that's about it in a nutshell. But the roof will be a standard style, with a 3-12 pitch, not a single slope. My cousin has a company that has been making and selling these kits for years, it's pretty standard.

http://www.balmezconstruction.com/Hay%20Barn.jpg

That is just an image I found on google, it's not affiliated with my cousins business, but it's a pretty standard hay barn. I can get it in any size I need, bigger just cost more, more materials and all that. They do these and pole house shells, workshops... that sort of thing. Not sure of the species of wood, but these buildings are designed to last for a long time with the poles just buried in the earth, I will be using concrete.

And yep, once I get the roof up, then I will ready the foundation, if not before hand, just a deep compacted gravel trench, with a few rows of tires also filled with gravel to keep it elevated. Then I will build the straw bales walls up underneath it, then finish the underside of the roof to make a good connection with the bales, finish the attic, and finish the overhangs like you would with any other house. Plenty of ventilation, plenty of insulation.

As for the greenhouse/atrium, just think of it as an inclosed carport. Below is a link to a picture that should give you a good idea of what I am thinking.

http://i01.i.aliimg.com/wsphoto/v0/560897701/bicycle-shelter-car-shelter-polycarbonate-solid-sheet-greenhouse-sheet.jpg

So the entire south side will be built like any other exterior cob wall, so I would only get the warm air from the greenhouse if I opened the house windows, but the sun will be able to shine through both during the winter, heating the interior. And during the summer will be too high to get into the house, so it will stay cooler. And with the roof of the greenhouse/atrium/carport thing being made of heat reflective polycarb, it will keep the summer sun from heating the greenhouse floor the same way it will heat the rest of the house during the winter. Or at least it will be very limited. I could even just make the roof out of regular sheetmetal roofing, like on the house, and still get plenty of light for summer greenhouse growth. I am going with the polycarb for that structures roof, because it will add more light, and diffuse it, as well has limiting summer heat gain.

As for the dimensions, I get that most people would think of 1200 sq ft as super small for a 3 bed 2 bath, but I decided on this as opposed to a regular style tiny house. I had actually spent a great deal of time planning one of those, but I opted for more space for this build because I hope to have a family living in it. I think most modern homes are WAY too big, and really like smaller, much more energy efficient homes. So even if I go with a 30x75 or 30x80 roof structure, I will still keep the house dimensions 20x60. It is plenty of space, shallow enough to really benifit from passive solar heating, and well insulated enough and with enough thermal mass to keep AC costs way low during the summer. So much so that when I do switch to solar/wind after a few years, that I wont need nearly as big of a system as I would otherwise.

I know its an odd shape, and wouldn't pass the aesthetics test for most americans, and there won't be room for 7 flat screens, two living rooms, and a billiard/game room, but that's not what I want anyway. I grew up moving a lot, and have lived in 500sq ft homes, to 3-4k sg ft homes, and I like the smaller ones better, provided they have adequate sound proofing, lol.

I really like your drawings, I need to get myself in gear and learn to use sketch up, but the new job has been running me ragged, but I am adjusting, going from sitting on my butt in an office for the past decade, to running my butt off in a factory has been a huge change of pace for me, but I'm still relatively young, and am adjusting. I will email you requesting the plans here directly, I really appreciate the offer!

That is just an image I found on google, it's not affiliated with my cousins business, but it's a pretty standard hay barn... I will be using concrete.

So we are clear Dan, that is a Pressure Treated lumber structure and is not something that is appropriate to promote or discuss here, and if this is what is being suggested as the framing material, along with OPC (ordinary portland cements) embedding methods for the planed structure, I have to withdraw my involvement...sorry

OPC embedding post systems are doomed to fail in the long run, nor reflect the logic and wisdom of more enduring and pragmatic traditional systems. Also, treated lumber have zero applicability in permaculture or natural building. It will take another 50 years to even know if Acetylated wood is applicable to natural and sustainable building. Further more, "treated" lumber isn't necessary, nor does it have the extended track record of traditional systems of building such strucutures. I don't know of a single building constructed this way, or with those materials that will endure like the countless 300 or more year old barns I have worked with my entire life. These "kit structures" have a very limited viable or economic life span comparatively. This is not a place to promote or encourage this type of building at all in my view and only detracts from the core of these discussions to continually debate it. There are plenty of "main stream" and "modern" building and contracting forums dedicated to this "mindset" and way of thinking about architecture.

So the entire south side will be built like any other exterior cob wall, so I would only get the warm air from the greenhouse if I opened the house windows, but the sun will be able to shine through both during the winter, heating the interior.

And during the summer over heating this space and the reason I do not promote them and voiced considerable concern with most designs of this nature, I have seen that often fail to perform as intended. Planning (or hoping?) the sun's equinox will be at an acute enough angle to stop overheating is not worth this design approach compared to others. I have had this dialogue so often that I can almost "boiler plate" the conversation. I have these designs explained to me so often, just as in this case, as if the "planner" had built and designed 100's of them. The language is very "factual" and "directive" of will take place, and I can assure you from experienced...it is not the case at all, and if half of what is "planned" actually works I would be surprised.

It sounds like you have really set your mind and heart to the "ideas" you have of how this "should" work, so I will have to leave you to them and hope for the best outcome possible to take place...

Good Luck,

j