Building Planning and Massing
Building planning and massing converts program and site envelope into a building: bays, cores, circulation, and a shape that satisfies daylight, structure, and code constraints at once. The exam tests whether your parti survives arithmetic.
Core rules
- Set the module. A structural grid of roughly 24–32 ft suits office and residential; a double-loaded parking bay is about 60–62 ft deep (18–19 ft stall, 24 ft aisle, 18–19 ft stall). Grid dimensions should be multiples of the ceiling and facade module so partitions, lights, and panels land on the same lines.
- Core efficiency. Core and circulation typically consume 10–20% of gross area in office. That ratio rises sharply on small or irregular floor plates, which is why slender towers lose rentable area.
- Daylight depth. Useful daylight reaches roughly 1.5–2 times the window head height. With a 9 ft head height, that is about 13.5–18 ft per facade, so a dual-aspect plate of 60–70 ft works without supplemental strategies; deeper plates need atria, clerestories, or light shelves.
- Stacking. Align vertical shafts, structure, and major circulation through the full height. Special spaces - double-height lobbies, mechanical floors, transfer levels - should be placed where they interrupt the least.
- Massing as environmental response. Stepbacks for light and air, orientation for solar control, and articulation that reflects internal function all read as intent rather than decoration.
Worked example
A 24,000 GSF floor plate with a 15% core yields 3,600 SF of core and 20,400 SF of usable plate. With a 70 ft depth and dual aspect, each window serves 35 ft of depth - beyond the 18 ft daylight zone at the center. The fix is either a shallow court or atrium, or a narrower 60 ft plate: 24,000 ÷ 60 = 400 ft long, which may exceed the height-limit-related aspect ratio and forces a decision between daylight quality and plan efficiency.
Traps
- Letting the structural grid and the parking grid fall out of alignment, producing a transfer level.
- Drawing a deep plate with glazing on two sides and calling the center daylit.
- Putting shafts where they conflict floor to floor, which silently adds area to every level.
- Ignoring how floor-plate depth changes the core ratio and therefore the rentable yield.