You can remove your cofusion regarding wall in the blue print whether to be cosidered in inch or ft , be sure, it has to be in inches to be considered , with the scale of 1: 10 and specific mention of length of the wall 8 in , we have to cosider length of wall : 8 inch x 10 inch / 1 scale = 80 inches ( and not 80 ft ) , and in terms of ft it would be = 80 inches / 12 inches per ft = 6.6666 ft