Housing will never be the same, nor can it. No matter where one lives, fire, storm, tornado, insects, interruption of power, heat and cold, can suddenly make our home uninhabitable. Events half way around the world can determine energy costs and whether we can afford our overhead. In rural areas, fire insurance premiums can wreak havoc. The era of abundant cheap resource is over and we must adapt for own security.
Wood is an outmoded option. There is a turning to alternative methods, but they ultimately still rely on standard materials that just don't measure up. In our home, we're supposed to be King of our Castle, secure from exterior threat. In more dense living quarters, the notion has virtually faded from reality.
What is needed is superior material with superior technique. Concrete is a superior material in certain applications. Forming it escalates it beyond a residential economy. It's making a little headway with insulated concrete forms, sandwiching it between styrofoam, but then conventional materials are needed to encase and protect the stryofoam. The unequaled weathering durability of exposed concrete is lost. But at least, ordinary materials can still create a status quo appearance and that little glitch can be overlooked, although at a premium price.
Who is progressive enough to allow function, performance, and economy to trump conventional? Only that mindset do I address here. What follows is a presentation of simplicity joining with bulk material to create a much more natural, forever enduring, and sensible construction method that liberates one from external dependencies.
This has resulted from a degreed engineer going is own way into the wilderness in a beautiful yet at times brutal environment to learn what makes sense. A long persistent run with trial, error, and revision, answering only to what's most sensible, has evolved one person's solution. Doing everything by one's self uncovers foolishness and deception in a hurry. Problem solving is much more stimulating than capitulation to the ordinary.
For perspective, it's important to know the environment from which this arose and its attendant issues. Nine thousand feet in the Rockies brings extreme cold, wind, and fire danger. Clear days are not the norm, with clouds usually dominating the sky by noon. Prolonged winter high wind is the biggest nusiance of all.
The solution becomes obvious and applicable to any environment. Moderate the extremes. That's done with mega high mass, insulation, and solar input. HIgh mass must be accomplished with bulk material, as native as possible, even water, the best of all. These insights got me started in all this by building a rammed earth house with a concrete roof. Light weight materials are insulative. A major part of insulation is obviating air infiltration. Shrinkage and contraction of building materials with temperature and humidity fluctuations open passageways in the joints of all materials. Only a sealed loose bulk fill spanning joints can be effective.
An attached southwall greenhouse for solar collection and growing ability seems the most obvious first consideration. Gathering heat from outside the living quarters and storing it within provides the greatest temperance. Moving solar heated air under a concrete slab works best. A flat, crackfree, leakproof, concrete roof allows the easiest installation and maintenance of solar hot water devices. It triples as a scenic view patio and animal free gardening area. An enclosed stairway to the roof deck empowers an open door or window to vent heat from the house and draw in cool air through lower north windows. Transporting solar heated water, the ultimate thermal mass, to a resevoir under one's house is extremely sensible.
There is no hocus pocus here, only a simple minimally clever way to combine lightweight concrete and regular concrete in its most efficient usage. I'm no graphic artist, professional writer, or any glitzed out facade. I'm comfortable roughing it and have benefitted from foot travel experiencing in third world areas, particularly the Himalayas. With affordable housing becoming an ever increasing demand, simple heavy duty solutions are necessary to provide a global standard for housing mankind. When the durability issue is solved and return on investment is extended to virtual perpetuity, alot of good things become possible.
Clearing the beaureaucratic hurdle is always the biggest obstacle for change.That has been solved with the support of a professional structural engineer. This is not rocket science or dancing around issues. The structural method employed here is the same that's used in high rise projects. To bring a sixty story building method down to a two or three story residential use is what gives catastrophe resistance and long term survivabililty. The employed patented techniques bring down costs to below coventional methods.
I'm currently getting permitted to build in northeastern New Mexico on uniquely scenic property. If you, green alternative builder seeker, would like to participate in a grass roots reformation, this may be a timely opportunity. Call if you'd like to discuss. 303 567 2415.
Here's what it's about.
Superior Use of Materials
Lightweight Concrete Modular System for Manual Assembly
Cast in Place Regular Concrete Structural Frame
Fireproof, Floodproof
Basic Versatile Geometry
"Container" Wall Can Utilize Native Bulk Materials
Cavity width begins at 8" and may be increased in 6" increments
Two Structural Systems for Enhanced Catastrophe Survivability
Myriad Applications
PE Approved
Better than ICFs, SIPs
Slash Overhead
Virtually End Maintenance
Lightweight concrete is easily drilled, (much much easier than regular concrete) and will tightly hold deck screws if predrilled. The "concrete" term comes from the fact this volcanic product is glued together with "cement paste", same as regular concrete. By being still plenty strong enough means a 16" tall panel, 2" thick, and 12" wide will support 30,000 pounds before starting to crush. A better aggregate that costs 3.5 times more supports 60,000 pounds.
When one wants long term durability, impervious to the elements, a cement pasted product is the best you can do. For lightweight to "contain" a minimum amount of high strength normal concrete becomes a new superior hybrid.
A patented technique using lightweight concrete as a stay in place cavity wall for forming poured in place steel reinforced concrete structures.
The only drawback is thermal bridging. Although there isn't much conducting mass embedded in the panel, a steel pathway is not good. Previously that was solved by placing insulating spacers between the expanded steel fastening overlap. Now, nanotechnology has come to the rescue. An insulating paint developed for hot water pipes is used to dip the embedded portion of the expanded steel into, greatly retarding energy transmission.
Clamping the expanded steel overlap together with a single bolt, nut, and fender washers is the strongest, simplest removeable connection. The double thickness further enhanced by the addition of the fender washers creates a stiff, strong assembly at the center of the cavity wall.
This simple effective method of embedment and fastening is part of the patent for this system.
The old way.
Where a strong, torque resistant, joinery is needed with a one dimensional "slide-ability", splining is the proven technique.
The same principle is used joining wall panels together:
A narrow cut into the wall panel perimeter with a small tile saw removes a minimal amount of material yet creates a high strength spline groove for high strength polycarbonate plastic strips.
Ductile joints in both horizontal and vertical directions create a massive energy absorption system and damping mechanism helping to protect the internal cast in place column, beam, and slab primary structural system.
Panel geometry and the lightweight concrete facilitate simple manual installation of the wall system. Electrical outlets are cast into the panel, allowing simple open cavity wire routing and connections.
Plumbing piping sleeves and fixture mounting holes (shower/tub controls) are also provided during casting. A two inch thickness of lightweight concrete is the best fire rating available. Here it's standard inside and out. Water saturation only makes lightweight and regular concrete stronger.
A standard of one, two, and three foot long panels allow design flexibility and the ability to maintain symmetry and aesthetic regularity.
Artistic acid staining brings out the natural "grain" of the lightweight concrete and allows endless aesthetic possibilities.
One wants a mixer large enough to use a full sack of portland cement to eliminate weighing. A hopper to fill with aggregate than then dumps into the mixer helps with lifting. Five gallon buckets are a good standard measuring unit. A full bucket is 0.7 cubic feet. With good aggregate, one mix one sack portland to 7 buckets aggregate. For a lesser aggregate it's good to cut back to 6 buckets. If that doesn't create a good mix, one needs to employ creative efforts so as to not cause the concrete to weigh too much. Remedies can be found by adding certain admixtures (chemicals) to the mix such as super plasticizers and air entrainment.
One can even use wood carvings to make reliefs for placing in panel molds:
Components for walls, windows, and doors
Alternately flipped quoins create perfect inside and outside corners
A complementary column/beam structural system may be employed by using the cavity couplers as supports and fastening devices for form boards. The regular gridwork of the cavity couplers allows simple containment for incremental sizes of columns and beams.
Internal columns are formed by simply bolting OSB board to the expanded steel incrementally as the wall goes up. Sleeves 1/3 the column thickness may be placed for passage of wiring or airflow.
The space in the wall center is filled with lightweight insulating aggregate that also supports the beam during casting.
The cavity wall is the form or containment for a cast in place column beam high strength concrete frame.
Cavity wall removed for clarity.
The finished wall and stay in place forms create the perfect receptacle for pumped in place normal ready mix concrete for reinforced concrete columns, beams, and slabs.
Below are illustrations of how the cast in place structural system is created within the cavity wall.
On exterior walls and below grade foundations, panels are insulated with two inch thick polyiso insulation board embedded into the cement paste of each panel during casting. Where concrete is poured, it's only on the exterior panel face. Inside the structural frame, both panel faces are insulated. The remaining four inch cavity gives room to bolt the panels together in the cavity center. Subsequently, that four inch space is filled with insulating bulk lightweight aggregate, filling the cavity space, eliminating air infiltration, and creating a high strength solid composite wall. The entire concrete interior, wall panels and cast in place component, are insulated from the exterior creating a huge monolithic performing thermal mass.
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 bubblewrap 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. Radiated heat is felt as four degrees warmer than convected.
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.
Click on picture below for house design sequence.
If somehow there were to be a new castable material, that is one that is formulated in a flowable form, and then poured into a mold, there is one best way to maximize the utility of that material. This patented system is it. The same law of physics which is employed by using a roof joist in a vertical manner, or a truss which uses diagonal bracing between its extremities, or a steel I-beam, or a crane boom, wherever maximum stiffness is desired from minimum material, the principle is to rigidly place that material as far from the neutral axis as possible.
What is a neutral axis? That is the location in a composite construct where all the material on one side of it is in compression, and all the material on the other side is in tension. For anything to bend, the material on one side of the neutral axis gets squeezed, and on the other side is stretched. The resistance to bending is appropriately called "stiffness". Stiffness in the scientific world and or engineering world is measured by a unit called "moment of inertia". One does not need to know semantically how these words formulate that, as they signify an abstraction of higher dimensions. The typical unit is inches to the fourth power, one level above cubic inches which denote volume. The added power references a quality of volume, namely the stiffness of it. The actual formula is: (width x depth3) / 12.
Devil in the Detail Wall Cross Sections
Simple 40'x19' Cabin
(All my plans drawn with IMSI TurboCad ver 11.2 with .tcw format. They can be saved in .dwg format but don't know how well they'll open in AutoCad. Drawings saved as jpegs for simplicity of presentation.)
Post Tensioned House with Type K Cement
Engineering and Code
Code Compliance and Wall Cross Sections
Look at Lateral Displacement, Wall horizontal load handling
Code Items and Design Parameters
New Mexico Production Facility Structural Calculations
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Issues in Post Tensioned Construction from Concrete Construction Magazine
Concrete Home Information downloads
Nanotechnology Insulating Paint
New Mexico Alternative Methods Information