Mark Anderson

Thank you for the great responses; I will do a lot more research before I start digging and I'll check out the forum threads mentioned.

It's been a while since I've posted here, but I had a thought and would like some feedback on it. I'm very interested in walipini greenhouses and I've been thinking about how it would work to install a rocket mass heater along the back wall of a walipini and sit large water tanks on the bench part of the heater. The tanks could have fish growing in them with the fish water used on plants growing toward the front of the walipini, does anyone have thoughts on the feasibility in a system like I describe? Do you think it would be worthwhile to build something like this?

Thank you for the responses! It sounds like pumice could work as an integrated wall system if 4" of foam panel were put in the middle part of the forms in a 16" thick wall, which is thinner than a straw bale wall. My thought was that a mineral material such as pumice would have some advantages over straw bales in certain applications, though I do plan on using straw bales in my house project.

I've been thinking about a natural insulation/structural material that is not disturbed by humidity within the walls, and wondered if anyone has heard of using pumice? Here in western Washington we have access to a lot of volcanic material such as pumice (though it does have to be trucked over from the east side of the mountains). I've been thinking that pumice mixed with a little ceramicrete or mortar, then poured into forms, might make an excellent structural and insulated wall system. Many people use pumice for insulating their wood fired ovens, why not a whole house?

Seems like the best, most efficient, easiest to build roof for a round house would be a geodesic dome made out of emt (extruded metal tubing) google "desert domes" or check out kits from "pacific domes". A dome would more than double your interior volume, be super strong, easy for two people to build, have no need of interior load bearing walls, plus the dome shape naturally circulates air.

Have you considered using canvas painter's drop cloths? They are fairly inexpensive. The doping used on aeroplanes was made to be very light weight and slick, for a shed roof you really don't have that worry so I would recommend using an elastomeric latex coating which would be a more natural less toxic product. The coatings are used for sealing flat roofs, or old metal roofs on trailer homes etc... They can be tinted different colors, and life expectancy would be more than twenty years. You could even start with a layer of burlap, (burlap has large mesh openings which would allow the latex to soak through and adhere to the roof sheathing) roll the elastomeric coating onto it then put the canvas on while the latex is still wet, and another layer of the latex over the canvas. The canvas layered with latex has often been used on wooden boat roofs, so it must work pretty well. One other consideration is that using this method you could do some interesting shapes, you could even give the roof a thatched look.

Hey C.J. thanks for the link, wow, rice hulls sound great for a natural insulation material. The only all natural below grade insulation material I can think of is pumice stone, and I think it's probable the pumice could become infiltrated with water over time. Hmm... I'm sure there is something out there which could be used.

C.J. using clay slip for a natural fire retardant is an interesting idea; but... isn't clay a pretty good heat conductor, and wouldn't it reduce the insulation values of your wall? Also, if your insulation is between two earthen walls, it seems that there would be very little danger of ever having a fire in that space. I would also like to mention that straw bales will not burn, the material is so compacted that there is not enough oxygen to keep a flame going. There are straw bale homes in Nebraska that are 100 years old, I read about one that had a fire on the inside but the straw bale walls would not burn, it smoldered a little and that's all. It's kind of like trying to burn a thick book or Sears catalog, sure it will burn if you open it up and burn one page at a time, but just try to burn the whole book at once.

Yeah, styrofoam is nasty stuff, the chemicals that leach out of it in landfills have been linked to breast cancer, and ambiguouse sexual characteristics in babies; that's why I think one way to repurpose it out of landfills is to use it for insulation. Encapsulate it in the walls of a home that's going to last for generations. Seems dumb to buy foam panels at Home Depot, last thing I want is to encourage someone to make foam just for the housing market when so much of it is free for the taking. Thanks for the links, something that will make the outer surface of the foam sticky sounds perfect, that way I could just trowel the foam into my walls, or mold it into panels that can be cut with a hot wire etc...

There was a heated exchange on this site about "green cement" which I'm watching, since I would like to use a ferro cement over my tubular steel geodesic frame and recycled styrofoam insulation. There is also a spray on foam called "soy foam" but I'm not sure how "green" it is, besides the expense... at least recycled foam would be free, there may even be places that would pay to have it hauled off. There is magnesium phosphate cement called Ceramicrete or Grancrete, it looks very promissing since the ingredients are cheap; lime based cements take a huge amount of energy to produce and a very large percentage of green house gasses come from making conventional cement so I'm always interested in something greener and more sustainable that works like cement. The ceramicrete is supposedly 3 times stronger, fire proof, less than 1% water permeable, expands when drying, 30% lighter than portland cement, and a lot less expensive to produce... well, it sure isn't cheaper when I've found it for sale anywhere. The jury is still out on it, but I'm hoping it's as good as they say.

I'm glad I found this forum, most people on here are very helpful and patient. I'm interested in a life of quality, not quantity. My goal is a non-toxic, hand crafted, as natural as possible, home on a couple of acres classified as organic farm so I don't have to pay much in property taxes. It should be illegal and unconstitutional for the government to tax someone's home and property away from them. I knew people in Sequim, WA. who were retired on fixed incomes; when the area became a retirement mecca for the rich... taxes went up so much that long time residents lost their homes. This is one reason I've thought about building my little place on property that belongs to a big corporation, their little tax dodge could be my homestead until the day I'm caught living there. When I'm found out it wont be a big deal, I could just pack up and find another property to improve with permaculture. Gorilla permaculture... )

C.J. one summer I worked in an old apple orchard at Stehekin which is in the north Cascade mountains. There was an above ground root cellar built around 1918; it has thick walls filled with sawdust, when I was there in 1980 it still kept our sodas cold on hot summer days. For my little dome home idea I've thought about using volcanic pumic stone to insulate, there is a lot of it in eastern Washington (unfortunately that is over a hundred miles away). I have always liked the idea of using whatever is at hand to build with, to build smart and simple; there is no reason one couldn't have a warm snug and comfortable home made from local sustainable materials. My goal is to build a 900 square foot super efficient natural home mostly from recycled or onsite materials, for less than 20K. One idea was to collect clean styrofoam from packaging etc.. chop it up, put it in forms and add elmer's glue or ? to make it solid enough to use in walls etc.. Six inch thick panels would have a pretty good R value. Until people stop using styrofoam, it just makes sense to me to use it for the R value it provides instead of letting it go to landfills.

I've been thinking about using the ancient Roman hypocaust system to heat my home using a rocket mass heater, or a solar collector system to heat the floor on sunny days. The southern side of the dome will have a large window for passive solar, and the rest of it will be covered with dirt, soil, etc... except for a smaller window or door on the north side. I'm always re-thinking my plans, especially since coming to this site. I'm learning a lot here.

One thing is for sure, conventional housing is a racket; it seems insane to pay 300 to thousand dollars, and be enslaved to a thirty year mortgage on a modern stick built house that starts to rot as soon as it's built. I've been a handyman for a long time and involved with construction even longer, modern houses are toxic, inefficient, and dangerous... well I guess we already know all that here at Permies.

I had basicly the same question as CJ, wondering whether anyone knew if the mass inside an envelope of dirt under a layer of pond liner/plastc would have to be in direct thermal contact, not be insulated away from, the earth sheltered home. Paul Wheaton speaks about a heat cycle, and that when the amount of soil enclosed is a certain size it gains heat through summer, excess heat from the home, and releases the extra heat all winter. His point was that if it was done correctly, the home would never or hardly ever, need to be heated or cooled. I thought that if the home were insulated you would lose this effect. Has anyone had real world experience with this? I live in a moderate climate summer highs rarely above 80's, winter lows rarely below 30's (Pacific Northwest).