Takes 1 sheet of A4 2mm card.
Total size to be marked out. 180mm X 170mm
Each box is an 80mm cube. As it has to be glued along tab
lines, each box needs a 10mm lip at the end for the edge and a 10mm lip to support the roof.Basic roof would be built with an 80mm square of card, though you can make an 84mm square and add a 10mm lip to two edges which can be glued in place along the non lipped walls to make a stronger hold.
Once built cut remaining card into shapes, to add texture and surface to this build and you have a shanty ready for your 28mm war gaming. Playing with different idea's will allow you to build different shapes and different structures. Experimentation is the key.