Courtyard gardens are usually small and enclosed. The garden framework is significant here. Paving, walls, doors and seating play an important role in the garden. Some courtyard gardens can be sparse and minimalist while others are packed with plants and features. Many courtyard gardens will have limited sunlight so plant choice is vital
Costs: hard landscaping will be expensive
Maintenance: depends on what you go for . . .
Advantages: an extra room - outside
Disadvantages: none if you keep it simple