There is 18-30" or 24"-40"...

Im thinking 24-40 might be too big on most domestics as im around 6ft anyway. The reason im asking is in my own house obviously u cant reach the ceilings on your own so I measured up 24" up the wall with a tape and then a further 6ft. This showed me that if I was on a 24" set of stilts the top of my head would be touching the ceiling???

Any help appreciated