Seems like such a little thing: I took off the ridge cap from yesterday’s roof, which was made with cardstock, and replaced it with one made with standard copy paper. This cap is also narrower, and the shingles run vertically (as they should). In addition, I added a row of ‘vertical’ shingles on the rear loading-dock roof where it meets the wall of the main structure.
The photo may not do it justice, especially because I haven’t given it a spritz of Dullcote, but in person it makes a world of a difference.
I basically used the same process to roof the ice house, although I had to measure very carefully to account for the cupola, which is no longer removable (idiot that I am, I glued it all in place twice, and the second time around I used a lot of glue). For future structures, I will be sure to cut out the shingle-sheets before assembling each roof, so I will be able to use the roof pieces as templates. I could have saved myself a lot of time and effort if I had thought ahead about that. Anyhow, here’s the ice-house roof: