We have demonstrated $4/sq. ft. costs for lifetime building in the last post â€“ based on using on-site earth as a low cost building material. When our CEB machine is optimized to 3000 bricks per day, this option becomes really attractive as a viable option for global village construction.
When our sawmill comes on-line, we will eliminate more of the costs â€“ roof truss members, roof planks, top plate, plus window and door framing lumber.
Further cost optimization is possible â€“ without sacrificing any building performance. If we do the work in the summer, we will eliminate the need for cement mortar â€“ and go back to earth slurry as the mortar of choice. From our experience with the present CEB addition, we conclude that if we have sufficient roof overhangs on the building, along with proper earth berming â€“ then soil around the foundation will be dry â€“ and will become more dry over time â€“ such that additional moisture protection measures will not be necessary on the foundation and outside walls. Plus, we are convinced that cement-dipped CEB blocks can be used as a substitute for rock foundations â€“ so we will also eliminate the cost of gravel. The roof can be sheathed/shingled, and soil cement may be used to fill any questionable cracks. Nonstructural, insulating CEB block can be used to reduce the insulation costs.
The new bill of materials for the ~1000 sq ft structure look like a whopping $430 total:
This is 43 cents per square foot. People, this is radical, and hints at abundance. Just by having the infrastructure consisting of a CEB press, sawmill, and LifeTrac for power and earth moving â€“ we can produce housing at under $1/sq ft in outsourced building materials. We are assuming that LifeTrac technology is all under our control â€“ that we can fix and maintain it without having to buy any expensive parts. Maintenance cost reduction on LifeTrac relies on producing the steam engine propulsion system â€“ with integrated hydraulic pump â€“ currently in progress.
All of the above relies on good timing by working in the dry season â€“ where moisture does not turn our experiment into a mudslide. I can tell you â€“ these bricks are rock hard when properly cured â€“ but not so when they are wet. We will also consider simple kilning of these bricks, by arranging bricks into a kiln structure, and simply covering with corrugated metal. We can also consider using the building itself as a kiln â€“ by starting a fire inside during construction time, covering the structure, and letting it bake for a day or so. In situ kilning is not a bad idea.
On top of this, we can go even deeper in the future construction of our village. If we dig down, say 6 feet with the versatile LifeTrac backhoe â€“ we can make an earth-sheltered underground house. By using proper solar design and at least 1 foot of soil on the roof â€“ plus adding further nonstructural, insulating CEB bricks â€“ then we have not only created tornado-proof housing, but also reduced the cost by the price of industrial insulation.
Add a masonry oven with masonry chimney, with Nickâ€™s steam engine ($200) plus cooking surface â€“ an in-house well that we will dig with the future LifeTrac well rig â€“ and you have an autonomous house that produces its own electricity and water, is heated primarily by solar gain, and has accommodations for cooking, living, and working via wireless internet.
Two missing links that still need to be brought in from the global supply chain are mortar and nails. Well, weâ€™ve got that covered in the future. A small CEB kiln where we fire limestone is a time-proven technique for producing cement on a small scale. See Small Scale Cement Plants in the AT Sourcebook. The next one is metal melting â€“ and extruding a wire. Wire of different diameters is used to make nails, screws, bolts, and all kinds of fasteners. This is not a far reach for a small wire extruder â€“ if weâ€™ve got the know-how, and some scrap steel â€“ which today is an abundant, industrial detritus.
We will be building this concept house and revolutionizing the zero energy home industry â€“ our cost of under $500 for this is lower than the $10000k for structures of similar performance. The most difficult part will be laying bricks and cutting lumber. There is no substitute for honest labor with these, but brick laying can go at a rewarding pace. Both tasks are assisted with LifeTrac materials handling.
And of course, weâ€™ll cover glazing later â€“ if we have metal melting infrastructure, it is not a far cry to melt scrap glass, or even start from sand. Anyway, you get the picture. Absolute prosperity on a small scale â€“ if we integrate ancient wisdom with modern technology.
Welcome to Factor e Farm â€“ where we are building abundance.
You guys are doing well, but I didn’t see any labor hours included in the cost. How many man hours do you have?
Also, lumber is something that you will bring from the outside. For most places, we don’t have forests that we can cut down for roofs. For our underground house, we have used ferrocement for everything, walls and roof. It will last forever. It costs us just under $10/sf including electricty, windows, floors, everything finsihed out with passive and active solar heating and energy. Rebar can be made with steel extrusion methods and so can lathing and mesh. You can use roman concretes or gropolymers for the covering to bring the cost even lower.
What are you making the shingles out of? I think you guys should seriously re-evaluate your roof system. Concrete or even earthen domes will last much longer and will prove to be cheaper in the long run. Ferro cement houses don’t have to be buried to be tornado or hurricane proof.
But the earth blocks are a good idea on the walls. Many off-grid projects focus energy on the walls, like straw bales, earth blocks, adobe, papercrete, etc. But the real cost and longevity of a building is in the roof. Don’t make it weaker than the walls. It should be as strong or stronger. You can drive a full-sized backhoe on top of a ferrocement dome. Could you do that with wood trusses?
Also, I assume you are using wood for a bond beam? A good excercise here is to examine really old buildings. Like more than 1000 years old. They rarely have any wood. They are built round, usually out of earth or geopolymer and have earthen roofs, usually domed or arched. That is real longevity right there.
Also, for and in-house well, that’s a no no. Check out rayon and other underground gases. Put it outside, or at least in a separate building.
Good work you guys! Great to see the progress.
there is no well inside the house
the wooden trusses were designed to support a living earth roof, so probably several tons of soil. There will not be shingles
Ferrocement does not have the same insulative value as the CEB blocks they are using. They have used earthbag and cordwood for other structures, but they like this method for large scale building. Cordwood, given the wealth of availability of saw log in our bioregion, is possibly one of the most appropriate. However MidWest Earth Builders and many others in the midcontinental region have found CEB to work very well.
For the windblown loess soils in the grand river basin, NW missouri, CEB works excellent because the soil is practically ready for CEB pressing.
In our bioregion, there is a wealth of forests. This is why they are developing small scale sawmills, so that people can mill it for their own use insted of having to pay to have it milled. This would reduce their cost by several dollars a square foot.
What do you know of which is appropriate with what they have that could be used to support a living roof? Can ferrocement be made strong enough to support that kind of weight? Also, they have not developed metal extrusion for rebar, so that will take some time. Steel is very expensive now.
As far as ferrocement is concerned, they are looking into using ferrocement for catchment cisterns and possibly building. They are designing a kiln to make their own cement from limestone, as well as for firing dishes and other uses. You should read the last post, where they go into a lot of detail on their plans.
For the well, I was referring to the future plans for the well. They mentioned a well in the buried house for temperature control and water, but wells inside a dweling are a big danger.
Ferro-cement far exceeds wood in strength and longevity. Sure, it doesn’t have the same insulation value as CEB for walls, but if you are burying a house, that doesn’t matter. For living roofs and buried homes, ferro-cement is the obvious winner. There is no way you could drive a backhoe on top of a wood roof, but I have seen this done several times with ferro cement. It has the added advantage that it is fireproof, rot-proof, and is easy to build with minimal skills and tools.
The question “Can ferro-cement be made strong enough to support that kind of weight?” is really not appropriate, because it is the BEST solution for that kind of weight. Wood will fail inevitably, it is just a matter of time. I have seen ferro-cement buried under 4 or more feet of soil without any sagging or strain. I have seen them hold up backhoes and large machinery. It will hold the weight, and it will hold it for a long time.
The thing here we need to keep in mind is what is the BEST solution for replication in the Global Village model. Wood is not. The majority of the planet is brittle, non-wooded envorinments. It is great that they have plenty of wood in their area, and they should use it where it is best: for cabinets, furniture, floors, and finish work. But remember, if we are developing models here, we need to consider what the rest of folks have access to: clay, sand, rocks, some steel, some cement or limestone, and/or the makings of geopolymers and roman concretes (these are longer lived than modern “portland” and don’t require heat for manufacture).
For structures, earth materials are the most durable. How many wooden structures did the Romans build? How many of those are still around? How about the Greeks? Or Mayans? All of the major civilizations used wood as finishing materials, not structural. There are a few exceptions, but not many. Studying old buildings can give us clues as to what materials last longest and what methods produce the benefits we are looking for.
For me and my projects, we have these goals in mind: longevity, cost, skills required, replicable, and materials availability. For these goals, CEBS with a ferrocement living roof is the best solution for an above-ground building. For below ground, go ferro-cement and save a lot of man-hours.
I am right in the middle of building a section of our partially buried ferro-cement house here in Mexico. We have a few workers from the village helping us and none of them had prior experience with this type of construction. It took about 2 hours per person to learn all of the necessary skills to build a ferro-cement house. We are nearly complete with the walls and have about 10 days so far in the entire structure, including foundations, walls (armature and concrete), electrical, window frames (passive solar gain), and finishing work like shelves and creative elements. This section of the house is just beyond 400 sf, and for this stage, including labor, we have $1,800 in the structure (that includes electrical, windows, doors, and structure). We’ll need another $1,200-$1,500 for the roof and finishing. Floors will be red bricks that we estimated at $500. So, for just under $10 a sf, we have a structure that is here forever, was built fast will low-skill levels, and meets all of our requirements.
All I am saying here is consider a better roofing system. CEB walls are great, so why finish with a weaker roof system? At the very least, do a CEB dome, that would be much better than wood roofs.
Abe, do you have someone with a videocamera to document your work, or could you invite some help with that? That would be extremely helpful, I think. 2 hours of skills sounds very interesting, like an immersion youtube kind of thing.
When I say “extremely useful” I mean “extremely useful for _many_ people”.
Following on Lucas’s comment – Abe – you need to document what you are talking about with video. A video is a thousand pictures, and a picture is a thousand words.
What you are doing can provide excellent side-by-side comparison.
How many people do you have working on the 400 sq ft addition? I am not yet convinced about the ergonomic efficiency of ferrocement. My readings from the AT Sourcebook indicated that it can not compete with the ergonomics of CEB – assuming a rapid production machine such as ours is used.
Tell us more about the relevance of geopolymers and Roman concrete.
Yes, we do want to consider the best solutions for _lifetime_ design.
Our 43 cents is materials only.
Probably not either-or, depending on availability of lumber, land and many other factors. Where I live there’s not much land or lumber, in proportion to people, so I bet we’d want to have living roofs of any kind. If the first user-communities are light on the land, they may not want or be able to build something that lasts for many centuries, if they are quite experimental or if there are regulations about how to build.
OTOH, this kind of friendly competition can only produce benefit for all, I guess. Soon I’ll start seeing “religious wars” like the ones that have been going on among lovers of different flavours of Linux, with people wearing asbestos suits and all that. 😛
Seriously now, I’m glad you’re all providing data and documenting stuff as best you can. IMHO, _this_ is what’s going to speed up the changing of what we humans do on this planet. Lots of serious fun to be had by all involved.
Yes, I do have a few videos, but nothing that would be good enough for a “how to” ferrocement. There are tons of resources online for ferrocement.
We have a total of 4 people working on the addition, and it is underground, which is why the walls are ferrocement (actually, the south wall is exposed because we are on a hill). The people are me, my wife, and 2 friends from the local village.
The reason I mentioned Roman concrete and geopolymers is because both of those could replace store-bought Portland cement. So, instead of a mix of 3 parts fine sand to one part portland, you could use your own customized mix. Roman concretes are very good for this and would greatly reduce the cost and environmental impact of concrete in general. Basically, you don’t need heat to make it, and it stands up much better than Portland, even in salt water!
I will try and get things together with the videos and some write-ups after we break for the holidays. It is hard to find time to document, so we usually do it after the project is complete, like we have done with the adobe t bricks, chispito wind generator, and other building methods on our site: velacreations.com.
For now, I suggest reading up on all the ferrocement sites and forums you can find. You can spray it, plaster it, even blow it up with a balloon, and there are tons of people doing it in every imaginable way.
Happy Holidays to all!
open source steel rolling mill, anyone? one mill with multiple dies could be used to produce rebar, bar, wire, pipe, etc…
Here are some simple questions on your project. Please fill out:
1. Size of addition
2. Cost of concrete/mortar for addition ferrocement walls
3. Man days required to put up ferrocement walls
4. Roof construction technique used
5. Specifications of rebar/wire used
6. Cost of rebar/wire used
7. Man days to install roof
Also, on Roman concrete – have you done this? Do you have a good reference on how to do this?
I ask the details on ferrocement because from what I know – it is definitely more labor intensive – as it can’t be mechanized. But, the longevity issues are in your favor. We’re finishing our roof, and I feel rather dissatisfied with the technology choice of trusses. I can’t see them being a lifetime solution: trusses with 2 layers of 7/16″ oriented stand board on top don’t sound like they would last more than 20 years, from the looks of it. Posssibly up to a 50 year life.
Congrats on all your successes. Looks like you all have been working very hard out there!
A couple questions…
How many hours do you account for in the ~1000 sqft addition? I didnt see it in the BOM.
When you say ‘lifetime building’, are you implying that the bricks will last one lifetime? How have you tested this? Also, how are the CEB bricks holding up in Missouri rain? It’d be great to see some sort of report on the ability of these bricks to hold up.
Also, did you ever use that fly ash? I know they wanted a report on how successful you were in exchange for letting you have it. Any success on that??
I would like to ask if you have a copy of Nader Khalili’s first book?
He created soil based bricks, then fired them, fusing the brick walls into one piece of ceramic with the use of 100 gallons of diesel fuel, gravity fed to a simple burner (like the round cylindrical propane heaters used on construction sites). This made them completely insect and draft-proof in addition to greatly increasing the strength (essentially the bricks were surface-bonded as a result of their being fused together).
If you feel uncomfortable with using diesel you could use a gasifier process to produce woodgas and burn that.
What we are trying up here in Canada is CEB/Strawbale hybrid. CEB walls – put on roof (nice big overhangs) – wrap north/west/east walls with strawbale South is glass exposure. Works like a charm, any thoughts?
[…] same chopped straw for insulation. If the bricks and hay are essentially free, we are talking of low-cost housing, and a super-insulated structure at that. The insulated cavity and its thermal performance is […]