Problem
As the life in a building changes, the need for space shrinks and swells cyclically. The building must be able to adapt to this irregular increase and decrease in the need for space.
Solution
Make at least some part of the building rentable: give it a private entrance over and above its regular connection to the rest of the house. Make sure that the regular entrance can be easily closed off without destroying the circulation in the house, and make sure that a bathroom can be directly reached from this room without having to go through the main house.
Related Patterns
… this pattern is the first which sets the framework for the outbuildings. Used properly, it can help to create Necklace of Community Projects (45), The Family (75), Self-Governing Workshops and Offices (80), Small Services Without Red Tape (81), Flexible Office Space (146), Teenager’s Cottage (154), Old Age Cottage (155), Home Workshop (157): in general it makes any building flexible, useful in a greater variety of circumstances.
Place the rooms to rent in such a way that they can double as a Teenager’s Cottage (154), or an Old Age Cottage (155), or a Home Workshop (157); give the private entrance an Entrance Transition (112), and if the space is on an upper floor, give it direct access to the street by means of Open Stairs (158). And give the rooms themselves Light on Two Sides of Every Room (159) and The Shape of Indoor Space (191) …
Alexander, Christopher. A Pattern Language: Towns, Buildings, Construction. Oxford University Press, 1977, p. 720.