[Ferro List] Hawk Nest Home & Land for Sale

[Doug Lacy]

Yes, the pumping or pump could be cost prohibitive from a certain point of view but this is an interesting point because I can show that the pumping or even hand bucketing is the base reason why this system still achieves a unique cost-effectiveness.  

The pump was a difficult obstacles but I found a deal, around 3.5 Gs, on progressive cavity pump that was intended for the food industry because it had a softer rotor that was made from stainless steel instead of the chrome steel that cement sprayer rotors are made from.  The 2 hp electric motor could easily handle the low demand cellular fill and neat cellular concrete has no sand and is non-abrasive so it was a good match for that particular job.  Too bad I couldn't have coughed up a Moyno 2L4 mortar spray rig because that could do both the plastering and cellular pumping.  

I am glad, however, that I had the chance to explore hand applied techniques because it has led to some interesting discoveries about HP mortar encapsulation of lath and the development of the fresh slip floating techs that had surprising benefits and it has allowed for the development of an all hand-tool version of the system -'cept for the mixer of course, oh yeah, and the hog ring tool would be hard to give up but doable with wire ties, and, of course, a compressor really helps that hog ringer tool work better and a compressor helps produce foam at an amazing rate.

That 8,000 dollar pump is a squeeze crete or Gypcrete Rig that has a mixer, sometimes a hydraulic bag lifter and mixer dump system and large diameter progressive cavity or squeeze-crete style pump set-up that can pump 1/4 inch aggregate.  This is a lot more than what is needed for neat cellular concrete pumping and mixing and I don't see how those guys can even cover their expenses at 1500 a day with one of those high dollar maintenance deals. 

 If you explained the low-wear and low-damage neat cellular material to a local plaster pro who has a little spray rig that can move several yards of material down a hose in an hour, like the 2L4 Moyno or size equivalent, they may even trust you with their rig and hose unsupervised for maybe 250 a day.  Don't tell them you are going to experiment with spraying shell material too because they probably won't let you near their equipment.   

My pump motor was improperly wired and blew a start up capacitor in the middle of the pour.  We finished the house by making a human chain of four people going up ladders with buckets of the light fluffy stuff and that worked out good but took 5 people at the same rate that one person and one pump could do.  Still, the labor cost of mixing, transferring and placing material, even compared to using on site easy access dirt of the same volume, is a tiny fraction with the cellular because the mixer and aerator is doing a big chunk of the work by almost magically producing the large majority of the aggregate literally from thin air.  The pump is equally as cost labor saving but can be a marginal or no savings if the project size were small enough.

To do a quick comparison to help bring this economy thing into focus using my most recent 30 bag shell project, With the sand cement and steel and all other materials, I used about 1/2 of a full ten yard dump truck load of material.  If I had built this same structure out of mud adobe like material, it would have taken 3 full 10-yard dump truck loads.  Forming that into bricks, transferring it into its place would be an expense that is beyond measure from my point of view but you can get the economy idea by just looking at the two piles of materials for the same job.

Also, cellular concrete is just a base way to demonstrate the system in its best spare-no-expense form that is easier to calculate its thermal performance and still cheaper than stick and frame. The project I am working now, however, the little sea-shell 30 mix house, allows on site material to be more practical because of the small size of the project.  The heating and cooling demands of this 640 square foot two story sea-shell rose bud looking thing is very different because of its compact size so just insulating the slab and footer allows the thermal mass to come more into play and that relieves the necessity for the semi-insulating cellular concrete fill. I am going fill with sand pack boulders and rocks with just a small amount of Dry cement powder layered with a light sprinkling of water.

 Economy of size and economy of form powerfully effect costs in surprising ways too and affect the success chance of a project.  Once we open our minds to consider something beyond what we have been habitualated into believing we need in terms of size, we find ourselves on a new frontier of architecture for quality of life, sustainability and effectiveness for providing homeownership where it otherwise could not be achieved.  The curvilinear architecture made possible by ferrocement means we can do a lot more with these smaller spaces than what our current imaginations are likely to be able to see and appreciate at this stage of exploration.  We are talking about a size scale range that is larger than travel trailer size but less than trailer house size but with a likely comfort level that is equated with mansions by most.   

That recent seashell house in Mexico City was great but it was single plate shell construction, no chance for customizing effecting thermal mass and insulation to an area, although not needed in Mexico City.  Also, the home had a design focus of ornate ness first rather than allowing practicality or utility of design based in the economy of form employed by nature, like in termite mounds, sea shells and bones, dictate the design first so the ornateness is revealed as a natural effect from giving those design parameters objective priority.  Those upper rooms could have been opened up a bit with tons more of natural light and natural convection by replacing the confining spherical forms with taller forms that flare up and out to balance light and dark in a sharper way.  

I am making some clay sculpture of the home designs and working out a good system for cranking out little clay sculptures based on wire frames with lift away pieces to reveal the innards of these life-like small home forms.  This work is no small task in itself but it is worth it because I am realizing it is not possible to draw any useful representaion of these complex curved forms.  I am finding there is just an innate limitation in making 2-D representaions of non-abstract natural geometry.
 Even when the clay sculpture is mapped onto the actual site it was intended for, the changes caused by fine tuning into the many specifics of a particular site causes the form to be transformed completely.  Still the clay model is very useful.
The potential diversity of home design is exciting from this perspective and I am glad to have the chance to explore these forms using more complete and meaningful principles economy of sustainability. 

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