The Io-24 The Io-24 — It’s built on a three-foot stemwall and has a diameter of twenty-four feet and a height of nine feet. Ideal Rental — Because it’s practical, simple and affordable, the Io-24 makes an ideal rental for one or two persons. No Wasted Space — The Io-24 has no halls or wasted space. But its living area is separate from the sleeping area. Small but Tough! — Like all Monolithic Domes, the small Io-24 will resist natural disasters and is super energy efficient.