The area is very important to consider because the granny flat cost can increase if you do not think it through. For example, if the street has limited access you may need special equipment to bring all the materials and machinery. This means that you will have to pay more than initially calculated. Plus, the soil in that area is also something to consider. Based on its type, the construction team may need to adapt which also means more money. Maybe they need to dig more or the soil needs special equipment, so keep that in mind.