The reason I used foamboard was that it'll last longer and won't damage as easily. Yes, when painted, it warps. But I learned to crack the other side to straight the walls out. You NEVER notice in my dios that the walls were originally warped.

Now, I suppose I could tape cardstock ON foamboard and go from there. Mind you, I had 2 boxes full of foamboard walls so I could use them over and over. That's also the reason why I used thick wood for the base and L-brackets. I can remove the walls, but I'll have the base that I can take anywhere and change the walls up as much as I want. Taller, shorter and at times, longer or shorter corridors.