This file explains about the Temporary Wooden Rib Support System which supports the American Ingenuity prefab panels until concrete is applied in the panel seams and on the entryways, dormers, link, cupola, etc.
American Ingenuity’s Prefab Home Kits are erected using a system to temporarily hold the panels in place until the seam concrete, concrete on the entryways, dormers, cupola and link has cured and the entryways and dormers are framed in. The system is dismantled upon completion of the dome and the 2x4s are recycled as part of the interior framing. Shorter 2×4’s can be used to frame the second floor perimeter knee wall. Behind this knee wall, electrical, plumbing or ducting can be run or the space can be used for storage.
The dome prefab panels can be a Do It Yourself project or a builder can be hired. Either the owner builder or the builder can hire the Kit Assembly Consultant to supervise the kit assembly.
The Rib System consists of using your own 2x4s, bolts/nuts/washers purchased from Ai and steel hubs on loan from America Ingenuity to assemble a free standing framework which matches the geometry of the dome. Or Ai can cut, drill and paint the ribs and ship the 2×4’s on the truck with your building kit.
- The rib system dictates exact panel placement.
- As the building kit is being assembled upon the temporary wooden rib system, extra 2X4s or 2×6’s for larger domes are used to support the panels and the steel hubs.
- The steel hub rental charge is a $800 deposit with the hubs being kept for five months. After that the rental fee is $20 per month. The bolts/nuts/washers are purchased from Ai and are not returned. If the hubs are returned to us intact within the five month period, the complete deposit is returned. Thereafter, we subtract $20 for each additional month the hubs are kept and we subtract money for each hub that is missing and return the deposit difference to the client. The hubs are returned to Ai via UPS or common carrier at the client’s expense. Please box the hubs in a sufficient number of boxes to assure that the boxes are not too heavy for the trucking company employees to move around. When boxes are too heavy or improperly taped, they rip open during transit with hubs lost along the way. Please reinforce all interior sides of the boxes with extra cardboard to toughen the sides.
- The Rib System is bolted together from your 2x4s (or 2×4’s purchased from Ai) and color-keyed hubs on loan from Ai. The preferred method of assembly is called the “Bottom Up Method” where the riser legs are installed first. Call or email us if you would like to receive a document describing the rib assembly.
- The advantages of using the Rib System Option are:
- With a Rib System in place, a crane can be used to set 1 row of panels in one day.
- Since the Rib System reflects the dome geometry, a panel cannot be inadvertently positioned incorrectly.
- The Rib System is utilized for all the different dome size assemblies.
Q: Can I purchase the 2×4’s for the rib system precut and the holes drilled in them?
A: Yes. Due to fluctuating prices on the 2×4’s please call us for pricing. The pricing will be for the 2×4’s precut to the proper length with a predrilled hole. The 2×4’s that are used are lightweight wood, not pressure treated. We ship the precut, predrilled 2×4’s on the truck with your building kit. Remember these “supports” are temporary there is no wood in the shell to interrupt the insulation or to rot or for termites to eat.
Q: I would like to have the rib system assembled by the working consultant. Will the working consultant cut the 2×4’s to length, drill the holes and assemble the wood skeleton? A: He could. But it would be most cost effective to purchase the precut ribs from American Ingenuity and have them shipped on your truck with your kit. Or Ai can email the cutting specifications for them to be cut on site. Click on Kit Assembly Consultant learn how he is best utilized.
Q: How many 2x4s are needed for the rib system? A: The 15′, 18′ need 75 - 2×4’s. 22’ and 27’ need 75 - 2x4s eight feet long. The 30′, 34′, 36, 40′ require 135 - 2x4s eight feet long. The 45′ and 48′ require 135 - 2x4s ten feet long.
Q: Can I remove the temporary supports too soon? A: Yes you can. The dome shell is not self supporting until all the panel seams are concreted with two layers of concrete and all the building options have been concreted and the entryways and dormers framed in. The Assembly Manual that is shipped with each kit contains complete details.
Q: Why can the dome shell be self supporting with no need for interior load bearing walls to support it?
A: Manufactured geodesic dome home kits are constructed using a triangular network to form a spherical shape. The triangle shape is the strongest shape known to man and with the seam areas acting like steel beams. (seam areas are about 3″x5″ with overlapped, locked steel mesh and onsite concrete applied. Concrete averages two inches thick). The geodesic dome construction method using triangles, provides for a free-span, self-supporting structure requiring no internal supports such as roof load bearing partition walls. This allows for maximum flexibility of floor plan design and utilization of interior space. Suspension rods with top plate can be installed in the seams during kit assembly to support second floor areas. If there are not second floor framed walls to hide the suspension rods, some rods may be visible. During finishing the exposed rods can be covered with PVC or wood.
As an architectural form, the dome is one of the strongest structural forms devised and built by man. Domes that were built centuries ago enclose many of the great cathedrals of Europe. Domes are structurally superior to rectilinear enclosures. The partial sphere is an aerodynamic shape that is very stable in high winds and can withstand heavy snow loads. For these reasons, residential domes greatly exceed the structural requirements of the major building codes in the United States.
The dome, or partial sphere, is a geometric form that encloses the greatest amount of volume with the least amount of surface area. Historically, massive domes constructed of stones, brick or concrete were common in ancient Greece and Rome. In modern times, Buckminster Fuller was the first to formulate geodesic principles for constructing a spherical surface by triangular subdivision.
Q: What methods are used to lift the panels?
A: The methods used for lifting the panels includes; Man lifts, Small cranes and Highlifts (all terrain scissors forklifts often used by roofers).
Monthly rentals on transverse lifts also called Boom Lifts, Horizontal Boom Fork Lifts, Roofing Lifts, Shooters are available from National Rental Chains like US Rentals, Hertz Equipment Rentals, United Rentals, etc. The companies can be found in the telephone book
Ai now has lifting spikes that can be borrowed for a $100 deposit. It makes the attachment of the panels to the hoisting mechanism easier.
Tools and Materials needed to assemble the Rib System:
- Set of steel scaffolding to reach at least the dome height plus three feet (the dome height can be estimated by taking one half of the diameter of the dome.)
- 9/16” wrenches and ratchet
- 46 hubs, 255 bolts, nuts, and washers (borrowed from American Ingenuity) (three frequency domes 30′ - 48′)
- 15 diagonal braces: 2x4x8’ studs
- Vertical support for under each hub.
- Precut and color-coded wood ribs (2×4’s used are lightweight wood, not pressure treated).
- The 40′, 45′, and 48′ rib system requires 135 - 2×4’s
- The 22’ and 27’ need 75 - 2×4’s
- If you do not want to buy the 2×4’s and cut them to length, color code them and drill the holes, purchase them from American Ingenuity. Due to the fluctuating cost of 2×4’s pricing is determined at time of purchase.
- Two pounds 12d or 16d common nails
- 400 Galv. 2 ½” deck screws - if three freq dome
- 60D Nails for top of Support boards
- 3 – rolls soft steel Tie Wire
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27′ Dome being assembled with rib system
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34′ Dome being assembled on top of full basement
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The rib system has been assembled using the steel hubs and 2×4’s.
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The riser wall and one row of triangles has been installed onto the rib system.
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