The way to go dome

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Not all the good ideas for energy conservation are new ones. Some are decades or centuries old and are being rediscovered and adapted to today’s urgent need to be more frugal in the way buildings are designed and built.

A classic example is the dome, which has been used for centuries. Examples include the Pantheon in Rome, the Duomo Cathedral in Florence, Italy, and even the igloo.

A more modern variation is the geodesic design.

Today, domed structures can be found for every building type, from two-car garages to stadiums, churches to offices, and houses to warehouses.

The modern day dome was originally developed in 1922 by a German inventor and popularized in the 1950s and 1960s by American futurist R. Buckminster Fuller (1895-1983). Among his most famous buildings are Spaceship Earth at Disney’s EPCOT Center in Florida and the Climatron in St. Louis.

A geodesic structure is composed of a repeating network of triangles. Although it looks like a dome, it is actually composed entirely of flat surfaces. The dome’s nearly spherical shape enables it to enclose more space with less surface area than a rectangular structure. Strength comes from the egg-like shape, further reducing material costs and structural support.

These advantages translate into:
• Rapid construction without heavy equipment.
• Light-weight materials that can be erected by inexperienced two- to six-member crews in two days or less.
• Low construction costs.
In fact, construction is so light, quick and easy that half of all sales are made to owners who do their own erection.

Simple and sensible

Dozens of manufacturers supply pre-engineered kits that builders can erect on a prepared foundation. Off-the-shelf designs are available for a variety of sizes, configurations and building types.

A church, for example, might have two domes — one for the sanctuary and the other for a fellowship hall — joined by a narthex. The dome gives an exalted feeling to the sanctuary and plenty of ceiling height for basketball or badminton in the fellowship hall. Or a custom design can be created by the manufacturers, usually at no increase in cost.

Because of the inherent strength of the shape, dome buildings are well-suited for difficult locations, especially those subject to extreme winds such as tornadoes and hurricanes or earthquakes.

Advocates of green building appreciate the dome’s design. Heating and cooling the dome is more efficient because air circulates naturally with few (or no) sharp corners to trap heat. Domes are especially well-adapted to solar panels. One surprise for owners might be the excellent acoustics of dome buildings, especially churches, where the sanctuary typically is open.

Variations on a theme
Three variations typify today’s options in construction components suitable for light construction applications:
• Wood panels, by Oregon Dome, Veneta, Ore., 800-572-8943, www.domes.com
• Steel-reinforced, super-insulated concrete panels, by American Ingenuity, Rockledge, Fla., 866-524-3663 or 321-639-8777 or www.aidomes.com.
• Concrete (shotcrete) applied on an inflated form, by Monolithic Dome Institute, Italy, Texas, 972-483-7423 or www.monolithic.com.

For a  more complete list of dome building manufacturers, visit www.thomasnet.com and search for dome. Some links in thomasnet are broken.

Oregon Dome publishes a list of prices, ranging from $13,000 to $65,000. Prices typically include design and the services of a factory specialist to supervise the dome raising. Accessories that complete the framing of the dome are available. The most expensive is $9,800.

Standard packages are available for houses and garages. For example, a 45-foot-diameter Pioneer dome package provides 1,466 square feet of living area on the first floor and 572 usable square feet in a loft.

How big is big enough?

Geodesic buildings typically are described by their diameter. For example, “30 ft 4 freq.” indicates a diameter of 30 feet and a height of 15 feet. The higher the frequency, the more spherical would be the shape of the dome and the smaller the triangles. An 8-foot triangle obviously is easier for builders to handle than a 16-foot triangle. The Web site for Good Karma domes has a detailed explanation with illustrations at www.goodkarmadomes.com/dome_basic.php.

After the geodesic building’s initial burst of popularity in the ‘70s, enthusiasm waned because its futurist shape was, if anything, too striking for some tastes. Further, the unusual shape required adaptations that took experience to work out.

Some typical questions, concerns and objections raised in a conversation about dome construction and dome living are discussed by online reference source Wikipedia on its dome pages at http://en.wikipedia.org/wiki/Geodesic_dome.

Yet, many of the concerns are moot points or can be explained quite simply.

Here is how Linda Boothe, marketing director for Oregon Dome, responds to some of them. Her comments are in italic type.

Concern: Spaces within curved boundaries tend to be less usable than within rectangles. The curved walls require either custom furnishings, 100 percent prefab design or an open spaces approach.
Response: That objection might apply to a second floor or loft upstairs. But geodesic homes certainly can have interior walls to divide areas such as bedroom and bathroom. A typical main floor will have 10 vertical walls and no curved surfaces.

Concern: Geodesic buildings are susceptible to leaks, due to the large number of edges created by the triangles.
Response: That’s why buildings are shingled. Any good grade of laminate shingles or shakes will prevent leaks.

Concern: Residential geodesic domes have been less successful than those used for working and/or entertainment, largely because their complexity makes for higher construction costs.
Response: On the contrary, repeating shapes make them less expensive.

Concern: The dome shape makes it difficult to conform to code requirements for the placement of sewer vents and chimneys.
Response: That is correct, but resolved with careful design.

Concern: Off-the-shelf building materials (e.g., plywood) normally come in rectangular shapes, and much material may have to be scrapped after cutting rectangles down to triangles, thus increasing construction costs.
Response: Wrong. One shape is a flip of the other. In any case, whatever waste there might be is on our end and would be reflected in our prices; and we certainly do plan to minimize waste.

Concern: Fire escapes are problematic for larger structures, and they are expensive.
Response: Indeed. Meeting codes is not difficult, just expensive. One solution is to use a lower profile dome without a second floor. We recommend this approach for most commercial buildings. Again, simple and repetitive is the way to save money.

Concern: Windows conforming to code can cost anywhere from 5 to 15 times as much as windows in conventional houses.
Response: Wrong again. We use conventional lines of windows in our domes. Windows certainly can be customized, but it is not necessary. As before, to the extent this might be a problem, it is addressed at our end, since we ship framing ready to receive the windows as specified by the owner and contractor.

Concern: Professional electric wiring costs more because of increased labor time.
Response: Not true. Where there is curvature as in a loft room, we use more interior wall lights.

Concern: Air stratification and moisture distribution within a dome are unusual and tend to quickly degrade wood framing or interior paneling.
Response: In a dome, you don’t get air stratification because it provides continuous air circulation. Bathrooms and kitchens are vented to the outside, and if the owners use the vents, interior moisture is not a problem.

Concern: Privacy is a problem because a dome is difficult to partition satisfactorily. Sounds, smells and even reflected light tend to be conveyed through the entire structure.
Response: If you try to live or work all in one room, this is true. Framing to the ceiling will provide sound and light separation.

Concern: Floor space next to sloping walls can be difficult to use due to lack of headroom. This creates a volume that might require heating, representing an energy cost, but that cannot be lived in.
Response: As said, some edges in a loft might have less than 5 feet of headroom. So make it a closet. But it is not a heating problem because air circulates.

Concern: The circular floor plan lacks the simple modularity provided by rectangles. Furniture manufacturers usually design with flat walls in mind, so placing a standard sofa, for example, results in the waste of a half-moon behind the sofa.
Response: Custom furniture is a complex solution to a non-problem. Our ground floor typically has 10 flat walls. There are no circles inside the dome. When I design a kitchen, I make it with right angles so you can hang cabinets. In a bedroom, a pie shape becomes a closet. We provide simple modularity for the interior plan. Right angles come off exterior walls.

Concern: Dome builders, using cutboard sheathing, find it hard to seal domes against rain because of their many seams. Also, these seams may be stressed because ordinary solar heat flexes the entire structure each day as the sun moves across the sky.
Response: Same in a rectangular structure, only worse: hot on one side, cold on the other. It is the roofing that protects the building, not the framing.

Concern: The most effective waterproofing method with a wood dome is shingling, but even this can be a problem at the top of the dome, where the slope is less than that required by most roofing materials. One solution is to add a peaked cap to the top of the dome or to modify the dome shape.
Response: A cupola is a lovely solution. It gives indirect light and ventilation and permits a steeper roof.

Get volunteers to pitch in

Because of the simplicity of construction, some geodesic designs are suitable for projects that might have to depend on volunteer labor, such as churches and schools.

Concerned about a lack of emphasis on art, parents in a school district in Cottage Grove, Ore., began exploring ways to raise money for an art teacher and art building. They were successful on both counts, although volunteers would have to do most of the construction work. Fortunately, one of the volunteers was general contractor Swearengin Family Construction in Cottage Grove.

Ground was broken in fall 2007. The concrete foundation was created with Amvic insulated concrete forms. Materials for a 61-foot diameter geodesic dome was supplied by Oregon Dome. Swearengin expects the building, which will boast 2,941 square feet of space, will be ready when school begins in September.

Total contributions for the project will come to about $150,000 in cash, time and materials, Swearengin said, including $37,000 for the dome kit, which also was paid by a donor. To have completed the project at prevailing labor rates would have cost at least $250,000, Swearengin said.

Why a geodesic dome? The lead donor wanted a unique building and enough space for creative activities. The dome answered both needs at an affordable cost.

Niangua, Mo., responded to a different set of problems to build a pre-school. Located in tornado alley, the community needed a shelter that would withstand the destructive force of extreme winds. By combining both needs, the small school district was able to obtain a grant from the Federal Emergency Management Agency (FEMA).

The solution was a steel-reinforced, concrete building by Monolithic Domes. It will cost $311,750, with 90 percent coming from the federal government. The school was expected to have been completed in March. The 2,941 square foot dome has a diameter of 61 feet.

The new building will enable the district’s preschool children to move from double-wide trailers — famous as tornado magnets —  to a secure facility that keep 400 people safe from extreme weather.

An important side benefit will be the anticipated energy efficiency of the building, according to David South, president of Monolithic. A dome can cost as much as 50 percent less to heat and cool, compared to a conventional structure of the same size.

“The energy savings alone will usually pay for the total cost of the structure within the first 20 years,” he said.

Schools, sports and shelters

Gyms are especially well-suited for dual purpose school-and-community shelter functions.

The construction method for Monolithic Domes is as unusual as the buildings themselves, South said. The process begins with the placement of a ring beam footing and the pouring of a circular, steel-reinforced concrete slab floor. In many cases, a stem wall then is erected to give the building straight walls and a more conventional look.

Next, crews attach an Airform, a tarp made of tough, single-ply roofing material, which is inflated using giant fans. Once the Airform is inflated, work moves to the interior where treated wood is attached to frame the windows and doors. Three inches of polyurethane foam is then sprayed on the rest of the Airform, and a grid of steel rebar is attached to the foam.

In the final step, crews spray on a layer of shotcrete that ranges from 4 inches at the top to 8 inches at the base. The result is a permanent and virtually indestructible building, South said.

The durability of dome buildings is no longer in question, although some of its advantages can be seen as disadvantages. For example, the Chinese Alliance Church in Wheaton, Ill., was designed for 250 members when it was built in 1993. Although its paired domes — one for the sanctuary, one for a fellowship hall — have served the congregation well, according to the Rev. Danny Ma, pastor, its acoustics are so good that they can become annoying. A whisper at one end can be heard clearly at the other end. Moreover, the church has grown to 400 members and is not quite sure how to expand the sanctuary.
But the congregation got exactly what it wanted when the church was built: a finished cost under $1 million (plus land), erection of the structure in one day, an exalted space with sight lines unrestricted by structural columns and a distinctive shape that has remained the talk of the community.

Oliver Witte teaches journalism at Southern Illinois University. Contact him at orlwjr@gmail.com

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