wait a sec. the middle part is 1.8m. the wals willbe ca. 0.12m so 1.8+2×0.12 = 2.04 fot middle entrance plus walls. the exterior walls are 2×ca.0.4m so you got 2.04+0.8=2.84
the house is 7m - 2.84 for entrance and exterior walls. so the rooms flanking the entrance are 4.16m/2 or 2.08m. so toilet and kitchen needs to be there.