From 21 Panels to 9: Two Generations of Dome Design
The number you should read first
Two domes sit side by side in a comparison. Same footprint. Same height. Same marketing language. One lists 21 panels. The other lists 9. A buyer skims past the number, treating it as an assembly detail. That is the first mistake.
Panel count is the one specification that cannot be faked. Thickness can be overstated. R-values can be inflated. But the number of panels is printed on every installation photo, every shipping manifest, every parts list.
A dome's panel count is a technical fingerprint. It records the product's origin: 21 panels marks the portable first generation, designed to be carried by hand. 9 panels marks the residential second generation, designed around an integrated insulated wall. The number is not a preference. It is a signature.Why 21 panels means one thing and 9 means another
Panel count is not chosen. It is derived. The chain runs: product purpose, transport method, maximum panel weight, panel count.
A dome built for remote deployment must be portable. Each panel must be light enough for two people to carry and a helicopter to sling. That cap — 25 to 70 pounds per panel — forces many small panels. A 20-foot dome needs 21 of them.
A dome built for living does not need to be carried by hand. Panels can weigh over 200 pounds and move by forklift. Fewer, larger panels. The same 20-foot dome needs only 9.
Panel count follows from panel weight, which follows from transport, which follows from purpose. Portable domes split into many light pieces — 21 panels at 25 to 70 pounds each. Residential domes consolidate into few heavy pieces — 9 panels at roughly 245 pounds each. Same floor area, two different counts, because two different purposes.What 21 panels cannot do
A 25-pound panel has no room for insulation inside it. The wall is thin — a single skin of fiberglass. The thermal job is handed to a separate layer, bolted on after the fact.
Twenty-one panels also mean twenty-one seams. Every seam is a thermal bridge, a path where heat and moisture slip through. A structure with 21 seams cannot hold a continuous thermal barrier, because the barrier is interrupted 21 times.
The moisture problem is worse than the heat problem. A single fiberglass skin breathes. Water vapor moves through it. With no vapor barrier, that moisture condenses inside the wall and degrades the insulation over time.
The portable path trades insulation for portability. A light single-skin panel cannot carry an integrated insulated core, so insulation becomes an external add-on. And 21 seams mean 21 thermal bridges and 21 moisture paths. The result is a structure that is easy to move but hard to keep warm and dry.The 9-panel wall that carries everything
Nine panels, each around 245 pounds, change what a wall can be. At 106 millimeters thick, the panel is not a skin — it is a sandwich.
The sandwich bonds five working layers. A 1.5-millimeter fiberglass skin faces the weather. A 103-millimeter closed-cell polyurethane core carries the insulation at R-28. An aluminum foil interlayer blocks water vapor before it reaches the foam. Nine panels create nine seams, not twenty-one.
Fewer seams mean fewer thermal bridges and fewer moisture paths. The insulation is not bolted on. It is the wall.
The residential path integrates the thermal barrier into the wall itself. A 106 mm panel bonds a fiberglass skin, a 103 mm polyurethane core, and an aluminum foil vapor barrier into one rigid shell. Nine panels create nine seams. Insulation, vapor control, and structure are a single component, not separate layers.The fingerprint that names the generation
The lineage of FRP domes runs in two generations. Intershelter, founded in Juneau, Alaska in 2005, built the first: 21 panels of single-skin fiberglass, a portable dome designed for remote deployment. MarsDome, founded in 2014, built the second: 9 panels of insulated composite, a dome designed to be lived in year-round.
| Fingerprint | First Generation | Second Generation |
|---|---|---|
| Panel count | 21 | 9 |
| Panel weight | 25–70 lb (11–32 kg) | ≈245 lb (111 kg) |
| Wall type | Single skin, portable | 106 mm insulated sandwich |
| Insulation | External add-on | 103 mm PU core, integrated |
| Vapor barrier | None | Aluminum foil interlayer |
| Seams | 21 | 9 |
| Purpose | Emergency, remote | Residential, year-round |
The panel count is not a preference. It is a signature. When the same two signatures — 21 and 9 — appear on another company's two product lines, each matched to a generation it did not create, that is not inspiration. That is a pattern. Twice is not a coincidence. Twice is a habit.
Read next: The Number Between Your AC and Your Solar Array — on what R-value actually controls. Or Noise: The One Problem Money Can't Fix — on why mass, not money, decides the acoustics.