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Corner Bay Windows
Corner bay windows in San Francisco add charm but should follow specific rules for street and property projections. These guidelines ensure the windows fit within set boundaries while maintaining a balanced design on corner lots.
How to design Corner Bay Windows in San Francisco?
A bay window may project over streets and other required open areas so long as it fits within a specific theoretical envelope. Such envelope begins at the "line establishing the required open area" and narrows along 45-degree angles drawn inward as projection increases. A bay window might extend over parts of a street corner, not within a 90-degree projection of either of the parcel's street frontages. While a "required open area" itself exists only within a parcel, the "line establishing" the required open area is a theoretical marker that extends beyond a parcel and, in the case of corner lots, onto a right-of-way. Therefore, bay window envelopes on corner lots may begin along any part of the line establishing the open area, including those parts of the line that are beyond the bounds of the lot.
As such, bay windows may extend over parts of a street corner, not within a 90-degree projection of either of the parcel's street frontages. Such bay windows must nonetheless comply with the three-foot restriction on projection applicable to both street frontages.
San Francisco Municipal Code