San Francisco Public Safety Building
Design Team:
Mark Cavagnero Associates
Consultants
ARUP + SOHA
Site Location:
San Francisco, CA, 38°N
Design Period:
2011-2013

The San Francisco Public Safety Building was a project to design a 300,000 square foot civic building to house the Police and Fire Department headquarters.

I joined the project during design development and was part of the exteriors team. The following is an explanation of my thinking behind a waterproofing solution at one roof edge.The program was a large residential development of psb townhouses

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The exterior concrete wall was hung off of the
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structural slab. Because of seismic considerations, the waterproofing needed to accomodate
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2"-4" of movement.

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A monolithic waterproofing membrane is necessary to protect the interior of the structural slab.
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A wood nailer attached to the top of the exterior wall provides a surface to affix decorative coping and other waterproofing.

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Flexible waterproofing bridges the gap and accomodates seismic movement, and
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metal flashing protects the primary waterproofing.

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Pedestals and a
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continuous steel angle attached to the nailer support the rooftop pavers.

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A metal track supports a small piece of expansion coping.
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A steel plate supports the pavers during a seismic event and also protects the flexible waterproofing membrane.

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The expansion coping allows the primary coping to slide during a seismic event.

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The primary decorative aluminum coping is installed over the expansion coping.

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Stone pavers are chamfered to be able to slide. The whole system accomodates seismic movement and provides two layers of waterproofing at the gap.

It also meets the design intent of having the top of the pavers flush with the decorative coping.