The Ecphorizer

Paint It Yellow
Gareth Penn

Issue #26 (October 1983)

I like to think that people who buy lemons are pioneers. I like to think it mainly because I've bought so many lemons. Lemon buyers are the people who lead the way through uncharted economic minefields. Our social usefulness is enormous yet is usually the object of much sniggering and tittering. Next time you don't buy something because it is a proven loser, don't forget to thank the guy who proved it.

[quoteright]The biggest lemon I ever bought was a geodesic dome house. I have been sounded out recently by quite a lot of people who want to know whether they should build one or not. My standard lecture on this subject is becoming a bore. I'd like to use this forum to set it forth in print, so I can just refer inquirers to it and keep the conversation on some more interesting topic, like sex.

Many people who ask me about domes start off with what I call The Pyramid Question. Doesn't it do something to your energy? Yes, it used up quite a lot of it. I mean, doesn't living in a round house rearrange your psychic makeup? Well, I don't know about that, but it did rearrange my financial makeup considerably. It gets worse from there.

The glossy color brochures that are put out by people who sell dome houses are masterpieces of understatement. The things they don't say would fill a Britannica. One of their favorite buzzwords is "efficient"   It takes less building material, they say, to build a dome than a conventional house of comparable floor space. What they don't say is that every 28-square-foot triangle in their kit was made out of a 32-square-foot sheet of plywood. You pay for what they lopped off at the factory. You also pay for all of your own scrappage. Their argument is basically true -- after you have carted off to the dump all the scrap lumber, etc. When you have done that, there is indeed less building material left standing on site. The rest has gone to join the other detritus of civilization in some landfill.

The typical penalty you pay for the wonderful experience of building a geodesic dome is 10% of your roofing material, 15% of your drywall, and 20% of your insulation. The problem is that manufacturers of building materials make everything in 4x8-foot modules with square corners. They don't make plywood, for instance, in triangles, stars, trapezoids, pentagons and parallelopipeds.

It's hard to make off-the-shelf building materials fit the domes. It's even harder to get a contractor to do it for you. Drywall contractors, for example, bitterly resent jobs where they are required to use trigonometry. It results in very high bids. When it came time for me to tape out my house, a job which in a conventional house would take one man at most 1-1/2 days to do, I got a bid of $3000. I did it myself - in six weeks.

Another phony claim is that domes are energy-efficient. The reason they say that is that since the dome has a near-circular crosssection, it presents less surface area to the environment per cubic foot of enclosed volume than, let's say, a ranch-style house. This is true. But they don't point out that you have to be 15 feet tall to get the full benefit of the enclosed volume. Heat-loss savings are actually marginal, and could easily be made up for in a conventional structure by doubling up on ceiling insulation or putting in doublepane glazing.

Code in most places in the Bay Area requires R-19 in ceiling insulation. Most of a dome is ceiling, hence most of a dome's insulation in these parts must be R-l9 or better. Everybody is familiar with fiberglass insulation, the fluffy stuff with the aluminum foil backing. It's easy to use -- you can just stuff it in and lop off the excess with scissors. It's also cheap. But R-l9 fiberglass is 6 inches thick. The stud space in most dome kits is only 3 inches deep. To get R-19 into a 3-inch space, you have to use solid plastic foam. It comes in 4x8-foot billets (with square corners). You have to cut it with a power saw, and dome kits take 14 different kinds of cuts, seven of which are mirror-images of the other seven. Laying this out and cutting it in such a way as to minimize waste is worse than one of George Towner's treasure hunts. Square foot for square foot, plastic is about four times as expensive as fiberglass. And by the time you've thrown out all the scrap, it's even more. And if it ever catches fire, it will take Red Adair to put it out. And some of the more interesting combustion products of foam insulation are carbon monoxide and hydrogen cyanide.

If you build a dome with a cupola, as I did - to let in light and air so the house doesn't look and smell like a cave - there is no place on the roof where you can put in a legal sewer vent. Vents cannot be placed within ten feet horizontally of any openable window. People have done it and gotten away with it, but don't be surprised if you get red-tagged by your building inspector. I know, because that's what happened to me, and it took two months of down time to resolve the problem.

Roofing is obviously a hurdle. Most of the work of keeping rain out is done by the pitch, the slope of the roofing. The higher the pitch, the less work the roofing material has to do. A very low-pitched roof requires special treatment, a monomeric membrane such as NeopreneHypalon, built-up/hot-mop, or tar and gravel. Needless to say, the very top of your dome house requires one of the above. Otherwise, domes are like all other houses - except that every couple of feet in each course of roofing, there is a joint angling in at 60 degrees, and the Johns-Manville people make all their stuff with 90 degree corners. Joints just have to be scrupulously flashed. If you go rustic and use shakes or wooden shingles, you'll have a house that leaks like a sieve. And there's the contractor factor again. Roofing contractors like roofing domes the way they like having double pneumonia.

Because of their configuration, domes eat up electrical cable like a cuprophagic Pac-Man. Cable is expensive. So is labor, and it takes a lot of work to run cable through a bend every couple of feet. Smart people build houses with long, straight runs for their wiring, which cuts down on labor, either your own, if you do your own wiring (which is what I wound up doing), or the cash you pay a contractor to do it for you, if you can find one crazy enough to bid on your job.

I mentioned taping out the dome. Sparking tape is the stuff that covers up the gap between pieces of sheetrock. Tape itself is dirt cheap, but it takes x number of hours of labor to put in a hundred feet of it. Increasing the amount of tape increases labor costs. The rule of thumb used in the building trade is that the linear feet of tape required to finish a house is roughly equal to the square footage. A 1500-square-foot house, in other words, should take about 1500 linear feet of tape. I built a 1500-square-foot dome house. It took 3000 feet - twice as much work.

The thing is, conventional housing built by pros is built the way it is not because builders are unimaginative sticks-in-the-mud who wouldn't know Bucky Fuller if he stepped on them. They do things the way they do because they are keeping down overhead, especially labor costs, to make their product economically competitive. Anything that requires modification of off-the-shelf materials potentiates labor costs, mostly for measuring, cutting and fitting. If you build a dome, you can count on having a number of occasions on which you will spend half the day paring and scraping on a four-foot-square chip of drywall, trying to make it fit a geometrically complex hole. I purchased 200 sheets of drywall to finish the inside of my dome. Out of 200, six went up as is, with no more modification than a hole here and there for a switch or outlet. 194 required higher mathematics.

If you're determined enough, you can do anything. You can make a dome kit work. I did. But the question is, do you want to build a house you can afford and want to live in and have enough time left for other pursuits, or do you just want to prove yourself the equal of Prometheus? Take my word for it, life is too short. Or as Prometheus himself so aptly pit it, "Deliver me!" 

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-Illustration by Burt Schmitz

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