	Original state	Layer	Approach	Method
Wall	Red brick wall without insulation. 370 mm solid brick masonry wall Insufficient thermal resistance	Performance layer	Cavity insulation	Inject loose or foam thermal insulation materials into the existing cavity of the wall to increase thermal resistance. Performance depends on the depth of the wall cavity
		External finish coat	Repair/replace external finish coat materials	Use paint or stone to replace/repair the external finish coat to protect the performance layer
		Performance layer & External finish coat	Internal Insulation	Add gypsum board to internal finish coat to improve thermal resistance.
			External insulation	Attach a double-glazing on the inside
			Ventilated facade	Attached rigid thermal insulation board and cladding to external finish coat to improve thermal resistance.
Window	Single glazing, Double casement window Insufficient thermal performance and poor sealing	Window system	upgrade	Add double glazing and install on existing window frame
			The second single/double glazing	add a single/double glazing inside
			Replace	Replace window with triple glazing
		shading	Fixed shading	Shading devices on the outside of the window, such as hanging, fixed blinds.
		shading	Adjustable shading	Adjustable shading devices on the inside or outside of the window, in the form of movable sun visors, blinds, etc.
		Space intervention	Enlarge windows	Enlarge original window and replace with new one
Roof	performance layer: insufficient insulation of precast concrete slab. Waterproof layer and leveling layer: insufficient thermal resistance	Performance layer	Asphalt insulation	Insulation between rafters and suspended ceiling to increase thermal resistance.
			Top floor insulation	Prevent thermal loss
			Flat floor insulation	Additional insulation and waterproof layer on the roof panel
		Performance layer & External finish coat	Green roof	Additional insulation layer, waterproof layer, soil and plants are provided on the roof panel
		Performance layer & External finish coat	Flat to slope roof	Add insulation on roof panel with hanging tiles to increase the thermal resistance