DOME HOUSING - PRO AND CON
From: Mike Voronyak <illuminated001@y...>
Date: Wed Jan 16, 2002
Subject: Cheap domes-Housing
Having been a Building contractor for over 40 years has taught me what is possible and what is not. keep in mind the winds you wish to survive will be more like 300mph, not 200, as someone posted. Few structures can withstand that. The overlying wind pressure as it passes over even the most aerodynamic dome structure will create a lift vacuum that will pick it off the earth like a dried scab and fling it into the maelstrom. Best bet is TOTALLY underground. If you insist you are exempt and still wish to build dome structures, then listen up. Cheap Domes can made.
First....dig a hole the diameter you wish, and plan on at least 1/3 of it underground to keep it anchored in place. This means concrete slab over crushed rock, with foundation to above grade level, from which point you want to attach the dome portion with steel bolts every few feet, poured in place as a part of the foundation.
Dome form can be achieved simply, by making a giant dome-shaped baggie, attaching to your new foundation
circumferance, inflating it, then spray urethane foam over it, to a depth of 6 inches thick, then a layer of chicken
wire all over that, and cover with 2 to 4 inches of ferrocement.That is absolutely the cheapest way I know to build
a dome. As a part of World Housing project, we built hundreds of these in Mexico, as housing, although above ground,
and they are very solid.
From: "B Taft" <btaft@xx...>
Date: Wed Jan 16, 2002
Subject: Cheap domes-Housing
Well here's someone with actual experience, great Mike. However I'd prefer using rebar instead of chicken wire. That's what the Monolithic people use. And for myself, I'd like to put six feet underground with sleeping areas there, with the living and working areas on the second floor. Hopefully the dome would withstand the winds being so anchored. As there are 1,000 mile winds on top of the jet streams that can whip to the ground, it'd always be a gamble but with a properly constructed dome the vibratory rate of the structure should be about as little as possible.
I recall some big winds in the Pacific a couple years ago that they figure exceeded 350 but didn't know for sure because the instruments blew away with the buildings they were attached to.
As for heating and cooling, it takes very little in a dome and if it were a third underground it should be
less yet. The foam outside the concrete seems to trap heat/cold much better than concrete over foam. The Monolithic
people have all sorts of information on their site that show this. I'll bet those domes you built in Mexico were
dandy to live in.
The Taft Ranch
From: "planetx2003" <planetx2003@xxx...>
Date: Thu Jan 17, 2002
Subject: Re: affordable dome housing
If you built one of these well away from major metropolitan centers & shorelines, in the foothills or rolling hills & buried it so only the very top was at ground level, it might be a good inexpensive way to go. The hills would protect from high winds too.
Try this: http://www.calearth.org/
Subj: [preparation2003] Helpful Information on Dome Homes
I recently wrote to seven of the most well-known and respected dome construction businesses about the increase of interest in their products. I received replies from three of the companies who all reported an obvious increase in interest and sales over the past three years. True, domes can withstand excessive winds and the like, but even the top of the line geodesic domes have a limit of about 200 mph. American Ingenuity domes - http://www.aidomes.com - did tell me, however, that they are in the process of building plans and construction of a dome that can withstand 300 mph winds and #10 seismic conditions. I'll check back with the other replies when I receive them.
It is actually the internal air pressure that bears the weight of the concrete. Or if you are using dirt as your 'frame' (instead of inflating the bag,) the dirt bears the weight. The plastic bag only serves as a barrier.
I am speaking here as a professional. I have 35 years experience in construction and have worked with stick built in place, panelized construction, steel frame and poured in place concrete (and prestressed). I have also designed and built a four frequency hub and strut icosohedron. (2X6 struts with infill). Certainly the thinshell concrete dome from the people in Italy Texas would be stronger than my building, and if you really wanted to put a dome underground theirs would be a good choice.
You have no idea how much time you can waste messing around with radial walls and curved ceilings until you have done it!
The cob construction referenced on the site:
<http://www.networkearth.org/naturalbuilding/honey.html> does not look as secure to me as they are presenting. There is no mechanism for locking the courses of bags together. The weight of the sand bags would make them slide horizontally under earthquake conditions. Even with a lot of rebar driven through the courses of bags, I suspect the same thing would happen.
For those of you who are considering a type of tornado shelter, consider getting a shipping container. Have it sandblasted and sprayed with urethane foam insulation. Bury the thing with some kind of access tunnel. Very strong and affordable. Cheaper than that are large culvert pipes.
Here is another alternative which I have contemplated but never built. Considering the various combinations of straw and binding agents such as 25% clay/sand mixes, it is obvious that there is a full spectrum of possibilities from adobe block containing a lot of clay and a little straw to straw bales with mostly straw and a veneer of plaster.
Here is a possibility that has high strength and binding that goes beyond adobe or straw bale construction.
Find someone who has done gang forming for concrete and have them design some large forms. For this technique using heavy duty forming technique, I believe only one tie about two foot up and another at the top (eight foot assumed) is necessary - go six foot horizontally. Two foot thick walls, and you need a sizable crew to place the material. Break the straw bales up and spread in layers in the formwork by hand. Have a small mixer with a peristaltic pump available to pump the binding material. The binding material will be a soil cement mixture comprised of 25% clay, 75% sand and enough concrete or gypcrete (a gypsum and concrete mix) to be equivalent to a two sack mix. The gypcrete guys will have the peristaltic pump and mixer. Pour the soil cement in with the straw in the formwork making it a continuous pour all around and to the top.
The end result would be very strong, fire resistant, and also a very quiet structure.
MONOLITHIC DOME INSTITUTE
How to Build a Monolithic Dome
1 The Monolithic Dome starts as a concrete ring foundation, reinforced with steel rebar. Vertical steel bars embedded in the ring later attached to the steel reinforcing of the dome itself. Small domes may use an integrated floor/ring foundation. Otherwise, the floor is poured after completion of the dome.
2 An Airform -- fabricated to the proper shape and size -- is placed on the ring base. Using blower fans, it is inflated and the Airform creates the shape of the structure to be completed. The fans run throughout construction of the dome.
3 Polyurethane foam is applied to the interior surface of the Airform. Entrance into the air-structure is made through a double door airlock which keeps the air-pressure inside at a constant level. Approximately three inches of foam is applied. The foam is also the base for attaching the steel reinforcing rebar.
4 Steel reinforcing rebar is attached to the foam using a specially engineered layout of hoop (horizontal) and vertical steel rebar. Small domes need small diameter bars with wide spacing. Large domes require larger bars with closer spacing.
5 Shotcrete -- a special spray mix of concrete -- is applied to the interior surface of the dome. The steel rebar is embedded in the concrete and when about three inches of shotcrete is applied, the Monolithic Dome is finished The blower fans are shut off after the concrete is set.
177 Dome Park Place - Italy, TX 76651
Tel (972)483-7423 - Fax (972)483-6662
firstname.lastname@example.org | Press Room
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