The materials costs were paid out of earnings, by the year. Soon after finishing the dome, additional layers of copolymer plastic sheeting were added from inside for insulation. Some areas still intact, received 9 layers of co-poly with air spaces between each plastic layer. Interiors are still in various stages of deferred completion. I mounted a regular paint roller on to a 16 ft pole and laboriously painted most all surfaces, reaching from the ground and from the deck on top.
Water run off tends to be more concentrated away from the arch seams.
Below is a photo from the fiberglass dome's first winter which shows the level purlins. These purlins were very minima, just enough to hold screws. In addition to them, i reasoned that roving would be a good additional measure to add. Admittedly, this was a wasted effort. See a wilder biaxial building concept .