In our warm latitude, this seems to be practical and an affordable way to create a weatherproof roof in any shape which may have gutters for rain catchment as contiguous in the roof shape. I am having success with chicken-wire or screen mesh to carry a canvas or cotton sheet over the shape...then coating once inside and twice outside with a 50/50 "lat-cem" mixture [latex exterior paint and cement powder with enough water to resemble cake frosting]. Allow a day to dry between layers. May add some sand to final top coat. It's great to build this on the ground and easily hoist it onto the upright supports with a friend or two. The weight is surprisingly small and durability in high winds and heavy rain storms is excellent. Proper attachment to supports is the key.