Shadiversity Winterfell Build

Shadiversity (the YouTuber responsible for increasing the use of the word Machiculations by 5,000%) made his own Winterfelll build (available on YouTube: Here). I enjoy seeing how different people interpret the same source material. I think if we built all of Westeros to this scale, we would need a lot more server space.
 
One point he made in a previous video on Winterfell (talking about the show's version of Winterfell), is that the flat roofs on towers would be a bad choice for heavy snow. He suggests that the snow would accumulate on a flat roof and not slide off, potentially causing weight issues.

I feel like the flat roofs in our version would probably cause the same problem. Are those canon?