The common parts of a property include: 

• The structure of the building (including foundations) 
• Roofs, chimneys, gutters, down-pipes, attic space 
• Common close stairwell, windows, doors, door entry systems 
• Backcourts and bin-stores 
• Common electrics, gas, water, rising mains, tanks, cables, aerial systems, stair-lighting. 

Please refer to your Deed of Conditions (Title Deeds) for further information pertaining to common parts of the building.