EarthCrete Systems

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To achieve energy independence, a large solar input coupled with massive storage is necessary. An attached south wall greenhouse provides solar heating input. Plenum fans high on the south wall suck in warmed greenhouse air and force it down under the first floor slab.

 

Hot water solar panels on the roof provide heat input to a pool of water under the first floor slab. Because water holds over four times the heat per unit volume over concrete, four feet of water is the thermal mass equivalent of sixteen feet of concrete. The water is infused with air bubbles to keep it fresh. A bubble wrap floating cover controls humidity and insulates the water surface to allow extra heat for prolonged thermal storage. A sun protected pond liner contains the water for a very long time. Drains and multiple water inputs allow for simple long term management.

 

The conductivity of the interior concrete distributes heat throughout for a full enveloping radiating mass for optimal heat distribution efficiency.

 

By maintaining a healthy greenhouse environment, one reaps the reward of organically oxygenated and humidified air for utmost invigoration, while reconnecting to the free natural bounty of the Earth.

 

Insulated Foundation

Having continuous insulation between the internal thermal mass and the exterior can be tricky. A solid concrete foundation wall supporting a slab is difficult to design without a continuous concrete path that will leak energy. Protecting exterior insulation can be an awkward process. This foundation cross section provides a simple solution and also displays possibilities for diverse approaches.  At minimum a two inch polyiso board is embedded into the cement paste when the panel is cast. Intense high frequency vibration coerces the lightweight aggregate to interlock like puzzle pieces fitting together. This packing displaces cement paste to the top of the mold when well graded aggregate is available. The tar paper polyiso face makes a tenacious bond with the cement paste.
 
Under milder requirements insulation of both exterior and interior panels will leave a four inch void that can be with concrete. An interesting composite is achieved, two inches of lightweight concrete, two inches of polyiso, four inches of normal cast in place concrete, another two inches of polyiso, and finally the interior two inch lightweight concrete panel. The interior polyiso might be eliminated to increase the cast in place concrete width from four inches to six inches.

 

Panel Porosity
One way of looking at lightweight aggregate is that it's basically big bang exhaust. It is magma, the hot coagulation of the primordial material which coalesces into planet, eventually is trapped under the crust, and is subsequently spewed under pressure to the earth's surface. The vesicular (formed with gas / air pockets) nature of the aggregate creates a highly irregular surface with substantial mini caverns. The aggregate therefore holds a lot of air and absorbs a lot of water, like a sponge. This quality allows the aggregate to fiercely hold on to air bubbles. One needs to go up to a spec al high frequency vibrator with triple weight capacity to dislodge the air pockets and achieve a glass smooth, zero void (bug hole), exterior surface.
 
The finished product can be likened to a carbon block filter, as it is porous and can wick water into it. This means that a concentration or puddle of water will be absorbed and diffuse throughout the volume. It will also pass back out in proportion to the outdoor relative humidity. Using sealers can easily be done, but upon investigation they seem to all allow "breathability". The real question of breathability is during a windy period how much air infiltration there is. The vertical surface sheds water quickly and the beveled joints keep the water going down. My ten years of living with this construction has been totally trouble free in the worst deluges. It seems breathability would usually be preferable to an impenetrable opaque coating.
 
If one wishes to use concrete dyes for the coloration and not acid stain, then a heavier release oil will absorb into the exterior surface upon which water will instantly be repelled. Over time if exposed to direct ultra violet, this property will probably degrade away.