4. Thermal insulation (Maximum one page): Identify an exterior wall of the selected building (item 2) where the most heat transmission occurs during summer or winter (attach a photo). Please explain why you chose that particular wall. Next, draw a scaled section (1:10) of the selected wall and include the materials used along with their respective thicknesses, based on your knowledge and opinion. Then, calculate the thermal resistance of the wall. Finally, propose the addition of a cavity or insulation layer to the wall to double its thermal resistance. Please specify the thickness of the cavity or insulation layer that you recommend for achieving this enhancement