The only permanent structure that was on our land when we bought is an outhouse. It's perfect... except for one thing... the roof leaks like a sieve.
It rains as hard inside the outhouse as rains outdoors - the worst part is sitting down on a wet toilet seat (or maybe it's when the toilet paper gets soaked, it's all terrible).
Our land gets a ton of rain (and snow!) in spring and fall, so we had to do something to preserve the building (and our sanity). The umbrella was an OK temporary fix, but we needed a permanent solution.
We found a roll of tar paper on the land - the previous owner had no doubt planned to tar paper (and maybe even shingle) the roof. So we lucked out materials-wise because we only had to buy the shingles.
Chris cut the tar paper into three strips in the right size to cover the roof with a 1-inch lip on all four sides, and we still have a ton left over that we can use for other projects.
We decided that it was safer for Ruby to climb up there than for Chris because she's pint-sized - we didn't worry about structural stability. Plus she's not afraid of heights.
This was one of those times where specializing by skill sets and physical capacities really worked well for us. Chris offered directions, support, and spotting from the ground while Ruby scrambled around the little roof.
She climbed up on the roof (with a big boost from Chris), lined up the tar paper, and stapled it into place. Being so short, it was tough to get up and down - the ladder was just a little bit short so she had to kind of "jump" on the way up and "hang" on the way down to bridge the gap between the ladder and the roof.
It rained that night. We waited an hour or so before checking the outhouse... and guess what?! It was bone dry!! We haven't even put up the shingles yet, and already we've solved the rainy outhouse problem.