City (With plenty of FISHy opportunities)...

[zizi666]

True, 5mm foamcore will give you much stronger buildings, and your walls won't have that concave look.
But do be careful with the glue you use.
I've got pieces that suffer from discoloration where to much glue was used (green spots). I now try to spread PVA thin and evenly before mounting the paper on the board.

[Commander Vyper]

True, 5mm foamcore will give you much stronger buildings, and your walls won't have that concave look.
But do be careful with the glue you use.
I've got pieces that suffer from discoloration where to much glue was used (green spots). I now try to spread PVA thin and evenly before mounting the paper on the board.

I don't use PVA, good quality prit stick (large stick does the trick, also use the highest quality paper you can, (I had mine printed out at staples on the heaviest weight I could).

[zizi666]

I don't use PVA, good quality prit stick (large stick does the trick, also use the highest quality paper you can, (I had mine printed out at staples on the heaviest weight I could).

I thought Priit wasn't permanent ?
As for paper, I print on 250 g/m2 coverpaper (about the heaviest my printer can handle)

[Modhail]

Thanks for the advice, Zizi66 and Cmd. Vyper!
Those paper buildings were designed to nest into each other for storage. If I added foamcore to the walls, I'd lose that storage feature.
I could try 1 or 2 mm thick card? That should just fit. Or Just try heavier paper (I used 160g/m2 for these, it was the heaviest the local shops had available).
I'm still deciding how much effort to expend on the paper buildings though. They're really only intended as a stopgap until I get far enough along with my scratch-built structures. Which means, depending on the amount of hobby time I can muster, they could be needed for only a few months, or much, much longer.  

Oh, and a question: Anyone have any advice on doing a roof?
I tried making one from card, with strips of tiles glued on. But despite pressing it all down with a fair bit of weight while drying it still warped to hell....   And I'd only done the first half of one side of the roof.

[Commander Vyper]

Advice on doing a roof? yup, use foamcore!