01H: Functional Diagrams — Bursting the Bubble

bubbleAn architect’s design toolkit is overflowing with artistic visual products such as matrices, partis, tables and mass models used to solve architectural problems. One of the most valuable and intriguing is the bubble diagram. The bubble diagram is a simplistic functional diagram drawn with scaleless circles representing spatial entities connected by lines to show relationships. It is basic yet meaningful…and ordinary yet masterful and is critical to studying how a home works.

When inspiration strikes any sketch-worthy material (envelope, wrapper, napkin) or location (bathroom, plane, meals, sleep) becomes my on-the-go studio. I scribble furiously producing diagrams that resemble tinker toy assembly instructions. They look useless to an onlooker, but to me they divulge intimate details about home flow. Once I made the mistake of showing a spontaneous creation (see below) to the teacher.


Pretending to be impressed, the teacher nodded hesitantly and tried to conceal a concerned grimace. What looked to the teacher like random coffee rings was the beginning of something marvelous in my eyes.

I draw bubble diagrams to translate the adjacency matrix into a visual spatial relationship. That’s archispeak for diagramming how the house works. It’s a matter of resolving and refining the way spaces interact which is critical to any successful design. Like other architects or creative types, I study the relationships with a sequence of functional or “bubble” diagrams. It’s hard to describe the bubble sequence. It’s simply a rapid and iterative succession of studies experimenting with spatial grouping, juxtaposition, consolidation and dissection to examine different flows until I discover the flow that works best.

Bubble 1 is my brainstorm diagram or initial thought burst to get information out of my head and onto the paper so I can think about and manipulate it. Without thinking about how the bubbles are arranged, I draw them and quickly connect related spaces to one another. At this stage, the bubble diagram looks like a child’s game I used to play called maze. My sister and I used a ball of yarn and wrapped it around everything in the room creating a massive web. Like the maze game, the diagram successfully illustrates the connection between objects, but the crisscross overlap makes it difficult to digest so I draw another one.

  • Note: For all the bubbles in this blog entry the dark-colored circles signify primary spaces, the light-colored circles are secondary spaces and the dashed outline cirlces represent tertiary activities. The solid lines show direct or frequent functional relationships and the dashed lines identify indirect or less frequent relationships.


In Bubble 2, I refine the diagram by grouping spaces with direct relationships. The adjacency matrix revealed some spaces are integral or dependent so I combined the Living-Dining-Kitchen and Library-Exercise-Master together. I also combined the Guest Room and Den because they behave like dual-use or swing spaces. That means the spaces share complementary activities or uses. For example, our guest room is occupied part-time, but when unoccupied we use it as a family den or children’s game enclave. So, this convertible Guest-Den gives us the flexibility of two separate entertainment areas or an extra bedroom when the need arises. Bubble 2 efficiently captures these relationships with fewer lines than the first one. I organized the bubbles to eliminate crossover and do you see what happened? Don’t be afriad to look really close, but not so close you smudge the screen. Can you see what developed? No, it’s not just a colorful composition. Organizing bullets to eliminate crossover develops home zones. The diagram delineates public zones (right side) from private zones (left side). This is a well developed bubble diagram and sometimes I stop here, but I’m an extremist who likes to test alternatives in search of a better solution.


Bubbles 3-6 explore calculated combinations of tertiary activites and secondary spaces with primary spaces. Sorry, I launched into archispeak again. That means I experimented to see how different space combinations worked. These explorations include different Entry-Library-Studio-Exercise-Hobby combinations


Bubble 4: Let’s see how the Library-Exercise-Studio worked together…


Bubble 5: I wondered if the Library-Exercise-Studio-Hobby worked together…


Bubble 6: The teacher likes the library with the master and I want a private studio.


At some point, I stop producing bubbles because I have to design the house. The diagrams shown here appear rigid; however, bubble diagrams are rarely as contrived as my examples. In fact, I sketch extemporaneous bubble diagrams over several days perhaps weeks at all hours of the day and night. The teacher and prodigy are accustomed to my midnight walkabout or dinner sprints to scribble whatever inspiration strikes me. This spontaneous race continues…not for the rest of my design, but for the rest of my life — architecture is not something I do. It is something I am.

Bubble diagrams are fun and anyone can generate them, but architects always remember the bubble diagram’s purpose. These diagrams are visual relationships that represent the most efficient or natural living flow and never directly become the floor plan until the architect seasons it with lifestyle, environment and neighborhood fabric.