Very cool project. Great attention to the real longhouse structure. You could use these photos to explain the Scandinavian longhouse at school/university!
Thanks Anselm, but I've really cheated and taken too many shortcuts for this to work as any kind of true model: the proportions, structures, and joins are far from authentic. For example, I deliberately made the house too short, so its footprint on the table isn't too big. I merely try to give the impression of a longhouse...
Anyways, roof structure is progressing, I can now separate the basic structure from the house itself. It holds together and retains its shape, and it will get much more rigid and robust once I start with the horizonal planking. Now would also be the time to think about which type of material to use for cover: thatch or shingles? I've ruled out peat roof at this point.