Good time to construct an underground shelter? (farmer, winter, negative)
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With something that size the airform cost will be the least of your expenses and worries.
Actually, that's incorrect. Concrete / cement is one of the cheapest building materials. The trick is getting it to cure in the shape of a house.
(The previous example of an airform 64' dia., w/ 4" concrete skin would run roughly $12000 for the concrete - slab and walls. A $25k airform is twice the cost of the concrete.)
The low pressure inflated form has been around far longer than "Monolithic Domes."
One pioneer is Lloyd Turner - - -
He and his wife sewed their own airforms, and made their dome-icile. Lloyd Turner - Flyingconcrete
The process is to inflate the airform, spray polyurethane foam (4" - 6"), hang rebar from the cured foam dome, incrementally shoot a concrete dome within.
Concrete itself may be cheap, but the equipment to spray it with shotcrete and the labor involved is going to cost you on a project that size. You're not getting that much concrete sprayed for $12,000. Not to mention the 6400 square feet of polyurethane sprayed at 4-6inches. That's easily going to be well over $20,000 just for the foam job, if not more. Then the excavation costs, then you got to add in all the other stuff....
Not trying to argure, just saying a dome that size is going to be pretty expensive no matter how cheap the airform or concrete is. Something like the hobbit house you linked to would be much more doable for an owner builder both labor and cost wise.
Concrete itself may be cheap, but the equipment to spray it with shotcrete and the labor involved is going to cost you on a project that size. You're not getting that much concrete sprayed for $12,000. Not to mention the 6400 square feet of polyurethane sprayed at 4-6inches. That's easily going to be well over $20,000 just for the foam job, if not more. Then the excavation costs, then you got to add in all the other stuff....
Not trying to argure, just saying a dome that size is going to be pretty expensive no matter how cheap the airform or concrete is. Something like the hobbit house you linked to would be much more doable for an owner builder both labor and cost wise.
EPS foam + cement house: JAPAN DOME HOUSE
(Imagine replacing the expensive EPS foam panels with inexpensive precast foamed cement panels)
LAMINATED FERROCEMENT
Martin Iorns invention : laminated ferrocement Laminated Ferrocement
Laminated Ferrocement was put forth by Martin Iorns, and his workers, who built commercial boats and other marine applications in the 1970's. . .
The technique is very simple. . .
You will need a mold which is water proof, as you don't want moisture wicking away from your mortar. On this mold a thin layer of 1/8th inch thick mortar is laid. Scratch this layer as needed, and push expanded lath into the mortar. Once this layer has been embedded in, fill the mesh with mortar until a 1/8th layer of mortar covers the mesh, and repeat the process. Theoretically two layers of mesh makes ferrocement but Dr Naaman suggests that three should be the minimum amount. Since the stresses opposed upon the ferrocement are pushed to the outsides, the mortar covering the piece should be only deep enough to cover the mesh (2 to 5 MM's). Martin Iorns used six layers for a product that was just less than an inch thick, but furniture, doors or doghouses probably would be fine at three layers.
(More details on the page)
The tirolessa is a great sprayer for smaller projects. It sucks down the air though and you really can't have a large/fast enough compressor while using it. Still the easiest and cheapest way to spray concrete for the DIYer IMO.
I've made lots of EPS crete with chopped up scrap EPS foam and portland. It makes the concrete a lot lighter but not as strong. I've experimented with different batches and ratios and have made some very EPS heavy mixtures that were a majority foam. I have about 10 cubic yards of ground up recycled EPS foam waiting to be used again. I wouldn't use it underground though, only where light concrete is needed. Grinding up scrap EPS is time consuming and messy.
Ferrocement is always fun and incredibly strong and uses surprisingly little amounts of portland. It would be a great material to build homes out of in certain climates.
I planned on doing this if HRC secured the election due to her enthusiasm for war with Iran and Russia. Now I foresee a significant threat towards "socioeconomic" unrest. I think our social fabric is unraveling and will likely get much worse.
I can't defend this big house against a mob. I could easily defend an underground bunker. Which, by the way, would be very easy to maintain at a comfortable temperature.
Maybe you could defend it. Then again... maybe the mob will decide to pour about 50 gallons of gas down the ventilation shaft.
Maybe you could defend it. Then again... maybe the mob will decide to pour about 50 gallons of gas down the ventilation shaft.
I have a design that can deal with that.
It is all about how you design the vent shaft.
A straight tube is useful only for weather shelters.
(And even they need protection, from the elements.)
The tirolessa is a great sprayer for smaller projects. It sucks down the air though and you really can't have a large/fast enough compressor while using it. Still the easiest and cheapest way to spray concrete for the DIYer IMO.
I've made lots of EPS crete with chopped up scrap EPS foam and portland. It makes the concrete a lot lighter but not as strong. I've experimented with different batches and ratios and have made some very EPS heavy mixtures that were a majority foam. I have about 10 cubic yards of ground up recycled EPS foam waiting to be used again. I wouldn't use it underground though, only where light concrete is needed. Grinding up scrap EPS is time consuming and messy.
Ferrocement is always fun and incredibly strong and uses surprisingly little amounts of portland. It would be a great material to build homes out of in certain climates.
Have you ever built any stressed skin sections?
Ferrocement skin + EPS crete + ferrocement skin?
Maybe you could defend it. Then again... maybe the mob will decide to pour about 50 gallons of gas down the ventilation shaft.
Save the gas, just plug all vents by laying something over it with a heavy rock on top. One CoG shelter was defeated in their startup test/evaluation with some branches and mud from on-site. When disabling ventilation, a combination of oil, dirt and water works very well because it basically gums up all the internal counter systems. You can clog check valves, diverters, flushers and even air injectors get all fouled up when basic batter trash is used. If all you have in nature, a whole bunch of pliable vegetation and branches can clog pipes pretty good. All you want is to keep the air from safely entering.
I think the hardest part most face is identifying the vents themselves. A good design would have decoy vents on one side of the plot with workable ones located on the other side and well camouflaged. Thermal imaging can easily catch the covert exhaust. With low cost add ons to smartphones, any Joe can now find exhaust vents. Intakes are a bit more tricky but once you identify the exhaust, the intakes are in the vicinity. Often a simple brush fire and watching for the tell-tale slip stream into the ground exposes the intakes. However, I find they are usually just lines up with all the other "out-of-place" bunker giveaways.
So, save the gasoline for the occupant's cremations.
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