EarthCrete Systems

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Here is a simple powerful way to make a wall that creates two units of interior wall cavity volume for each one unit of wall volume. The workhorse unit is a 24" long by 16" high by 2" thick precast of lightweight concrete weighing only 37 pounds. No other wall system gives more strength with the least amount of material nor has the versatility of applications. The product serves as a finished wall, stay in place concrete form, and a container for any bulk material. A cast in place concrete frame consisting of corner columns and a top bond beam further strengthens and reinforces the wall's structural performance. The efficiency and economy gained from this strategic use of materials is the best solution for ultra safe and energy efficient buildings, at or below the cost of conventional more vulnerable methods.
 
Other cast stone products are used as simply veneer, offering no structural enhancement to the building, and requiring an existing wall to place against. This system is self standing with an extra large footprint for stability and strength. These wet cast lightweight concrete panels are glass smooth. The panel perimeter is beveled 3/8". The surface is highly reactive to penetrating acid stain for brilliant coloration and can be cast with integral color pigments. It may be sealed or left porous. It can be exposed to the weather and the sun's ultraviolet indefinitely without deterioration.
 
The eight inch wide interior cavity may be filled with anything: dirt, rocks, sand, mulch, concrete, nothing, or whatever for limitless creative application. It's the best way possible to give high thermal mass. Because solar heated air or water can be introduced to the center interior of the wall, it becomes permeated as the heat conducts to the outside of the wall, allowing a prolonged, gentle radiance. This form of heat feels 4 degrees warmer than convected heat, so an immediate 4 degree temperature differential is pocketed as savings. During the summer, like in a cave, the high mass construction feels cool eliminating air conditioning.
 
Suffering glare and overheating from the traditional method of large south facing windows is eliminated. This technique has probably set back the acceptance of solar heating more than anything else. Wall and floor surfaces are easily overwhelmed from the rate of heat coming in being much greater than the surface being able to conduct it into the mass. The excess inflow is what causes overheating.
 
It makes traditional housing obsolete and not a minute too soon. With the dangers of fire and extreme weather being more and more problematic, taking refuge within an inexpensive reinforced all concrete home is the smartest move. The sense of security and comfort within a high mass enclosure is striking.
 
We are looking at change in the most fundamental way. Increase the mass of our dwelling by a huge amount. This most simple sensible idea flies completely contrary to our common sense. More mass is more weight, is more stuff, is more handling, is more money, and therefore is too expensive. However, we choose cunningly easy way to manifest mass. And, this mass is fireproof, vermin proof, immune to water damage, and will basically last forever. Houses aren't trivial things to buy and flip anymore. One needs low overhead secure sanctuary from which to venture out and tackle life, immune to budget devastation from spiraling energy costs.
 
The first mass is lightweight concrete panels that serve as the finished wall and a stay in place form for the second mass, regular concrete. This is a key efficiency as the major expense for using regular concrete is the forming expense. Precast lightweight concrete panels installed as the completed wall eliminate this expense. The most powerful procedure in construction is pumping concrete into place from ready mi x trucks. Concrete trucks are the heaviest vehicles on the road and they can deposit their load in minutes as they feed a pumper. This mechanical transfer of mass forms the internal structural frame within the wall cavity. It's insulated from the exterior wall thus becoming part of the internal thermal mass.

 

The third form of thermal mass is the most expedient of all. Water, like our oceans, is the ultimate for temperature moderation. It holds four times more heat than soil or concrete (62.4 compared to 15.7 btus per cubic foot). Foundation walls and the ground are a ready-made water receptacle. They are easily insulated with a 4" thick layer of polyiso for R-30 heat retention. The water is contained within a pond liner. Being protected from direct sun, it will perform for a very long time. Multiple layers can be installed for added insurance. The water is added through either roof run off or the water supply. Water needs to be aerated to not smell and remain fresh. A solar powered compressor serving submerged air diffuser stones will do the job easily. The expense and labor of embedding plastic pexpipe with n a concrete slab is eliminated. Since the structure is tied together with elevated concrete slabs, the material to form an elevated slab is already at hand. A drain under the foundation makes managing the water easy.
 
The high conductivity of even lightweight concrete enables the interior walls to conduct the heat from the water warmed base slab and conduct it throughout the building. Steady state equilibrium is established and all surfaces, floors, walls, and ceilings, become an omni-directional long wave radiating mass.
 
This three pronged strategy to maximize heat storage will see one through stretches of cloudy weather. In the West, winter weather patterns are usually the warm before the storm as cold air pushes warm air in front of it, then the temperature drop with the snow, and then clear after the precipitation moves out. Sun usually quickly returns after bad weather. Should power lines go down, small solar panels provide electricity to run low power circulating pumps.  Absolutely simple thermal circulation and storage is utterly reliable. The horror of losing power and therefore home heating after i.e. storms need not ever happen again.
 
All climates benefit from high mass construction. Even in desert extreme heat, walls can serve as evaporative coolers by spraying water on the interior faces within the cavity. When one employs solar equipment, it's a great help to have easy safe access to it. A flat roof gives that type of access that also doubles as a rooftop patio. Many concrete buildings in Asia utilize this feature.
 
The simplicity and efficiency of this system is using molds to make building pieces that fit precisely with each other. A mold doesn't seem like much, but that's the first big challenge to figure out. Because the building blocks (panels) fit in an abutting manner, flush against each other, the molds that produce these panels need to be extremely accurate. Also, the panel needs to be easily and quickly removed from the mold, which implies some sort of releasing and resetting mechanism.  Solving this riddle has been the most laborious and time consuming component in the development of the system. There has been a multi generational evolution of techniques gained from persistent experimentation and constant upgrading. Molds reproduce the accuracy of their formation to give a repetitive, precise product hundreds and thousands of times subsequent.
 
To have the right stuff to put into the molds makes them worthwhile. There is a very narrow range of what will work. When one speaks of lightweight concrete, it's usually a concrete that has its largest particles, (gravel aggregate), replaced with an aerated lightweight volcanic product. Regular sand is still used and the weight is reduced from 145 pounds per cubic foot to about 110 pcf. That's nice but is not light enough for our desired application. We need the gravel and the sand to be lightweight and get the weight to about 82 pounds per cubic foot. Lightweight aggregate, specified as a "quarter inch minus" mix will weigh about 57 pounds per cubic foot. That is as light as we can go and still maintain a strong enough concrete.
 
It has to be this light because the pieces are manually handled and installed. The most common form is expanded shale, although expanded clay and cinders can also work. The key is a "well graded" mi x, which means an even distribution of aggregate sizes. One does not want strictly coarse quarter inch and fines without the intermediate sizes. Although lightweight concrete is 40% lighter than regular concrete, panels still contain substantial weight. The predominant panel weighs 37 pounds. Installing this system has the fringe benefit of creating fit, muscular workers. Heavier corner and door frame pieces are easily handled by two people. The feeling of accomplishment that installation yields, going from empty space to a completed, superior wall, provides ongoing motivation.
 
Portland cement is Earth's best glue that ensures durability and longevity. It comes in the heaviest sack that can be carried. It's a simple one cubic foot unit of volume, weighs now 92 pounds, and costs about 12 dollars (up from four dollars about ten years ago). One can buy it in bulk for less than half that amount but then one needs to provide storage means (silo), depending on the seriousness and commitment of the operation. Investing in a silo along with weighing and dust control systems requires a sizeable investment. For now, we like our sacks, premeasured, standardized, and ready to go. This does require a large enough mixer, at least 5 cubic feet, to use a full sack of cement.

 

Beginning installation occurs on a concrete slab or footing. Slots are sawn into the concrete 10" apart to match the panel slot spacing. A four inch tile saw with a wet cut diamond blade works best, making a shallow cut 3/8" deep and 1/10" wide. At corners, the slots are of course at right angles. One then applies a thin bead of silicone in the slot followed by inserting the strip. The silicone is pushed out sealing the strip and eliminating any water path. Then the one piece corner quoins are placed aligned with the strips, and when they seat down they are rigidly locked into position and vertical is defined. The straight wall panels are then placed, abutting and aligning their slots with the strips. Each side of the wall progresses from the corners to the middle, where they meet. Vertical is checked and the couplers are bolted together, locking the wall into perpendicular.
 
Exterior panels are installed from the interior slab, using a rolling scaffold as the wall increases in height. No scaffolding or ladders around the building perimeter are needed. The joints around the panel sides are lightly grouted to seal the joint and round in the small crack space between adjoining panels. There are easy tasks for anyone to do, from children on up to seniors. It's a fun, easy process that quickly creates a super wall that's beautiful.

 

Lowest Cost

One employs the best biggest sack of glue, Portland cement, to bind volcanically aerated lightweight aggregate in a precision mold good for thousands of uses. Anyone and everyone can be involved doing productive tasks. Cutting polycarbonate strips to length, preassembling nut, bolt, and washer groups for ease of handling during fastening, cleaning molds for reuse, applying mold release, installing expanded steel couplers after casting, tightening nuts and bolts, precutting and tagging electric wires, there is so much to do at a leisurely pace. There is no pressure or urgency at all except for meeting one's goals. Another large benefit is that there is no waste therefore no onsite dumpster. Tri m and finish carpentry are eliminated. Drilling through framing for electrical and plumbing is eliminated.

The need to pillage foreign forests and their inhabitants is no longer necessary as wood is only used for column containment within the cavity.

 

Expertise Too

The big day is when the regular concrete is poured and pumped. The columns and beams are easy, but doing the slab is the call to experienced expertise. There is never too much help doing a slab. Modern concrete tools such as vibrating screeds, roller screeds, lightweight power trowels, and plasticizing admixtures help make it easier. However, the variables of temperature, wind, and strategy make every pour a unique experience. Accomplishing a flat level slab is a demanding work of art. It's a powerful ability to have and there are so many options for how it will look.