Summary of Work

In spring 2011, John Muir Health opened a new, $600 million addition to the John Muir Medical Center in Walnut Creek named the Tom & Billie Long Patient Care Tower.

BEST Contracting Services, Hayward, CA was chosen to install the roofing on the new addition and the Central Plant building, install vegetated roof gardens and waterproof the water feature in the lobby of this exciting new building.  

The existing John Muir Medical Center is a 324-bed acute care facility that is designated as the only trauma center for Contra Costa County and portions of Solano County.  Recognized as one of the region's premier healthcare providers, areas of specialty include high- and low-risk obstetrics, orthopedics, neurosciences, cardiac care, and cancer care.  The new addition contains many attractive features designed to make the medical experience more pleasant.  These features include several areas of roof top gardens and a water feature in the lobby area consisting of a cylindrical glass atrium extending to the open sky containing a vegetated “island” surrounded by water.

The new hospital roof utilizes an 80 mil thick, white PVC membrane to comply with current California regulations which prescribe minimum levels of solar reflectance and heat emissivity.  A similar but thicker membrane is used under the vegetated roof areas and in the lobby water feature.  The Central Plant is roofed using a 60 mil PVC roofing system in Dusty Grey color.  Walk ways around the vegetated roofs consist of pavers set on adjustable pedestals.  These adjustable support pedestals enabled the BEST crews to induce slight slopes for drainage purposes.

Challenges

This project posed many challenges to the crews including the many unconnected installation locations which made loading and accessing work areas very time consuming.  The main roof in particular is heavily congested with  copious amounts of air handling equipment and in all work areas of the project, the high concentration of “other trades” performing their own scope of work made progress slow and keeping the surfaces watertight very difficult.

Results 

This roofing and waterproofing project performed by BEST was an award winner in the 2010 Sika Sarnafil Project of the Year Competition.

Central Plant Roofing

Sika Sarnafil 60 mil feltback PVC color Dusty Grey installed over a lightweight concrete deck.

Typical Vegetated Roof Areas  
The paved areas around the garden roofs consist of concrete pavers over adjustable pedestals.  These pedestals allow the installation of a gently sloped roof for drainage or greater slopes to accommodate the transition between different roof levels.  These paving systems are installed over a full roofing system for a watertight finish.

Congested Roof Area
Typical of the roofing challenge around the air handling units, this photo provides some indication of the amount of base flashings and pipe penetrations needed to thoroughly waterproof this roof.  Throughout this project progress was slow due to the large volume of “other trades” attempting to perform their work simultaneously.