Case Study: Methane Consulting - Cedar Sinai Medical Center Los Angeles, CA
Methane Zone Level I | 3 Levels Below Grade | 67,032 SF Footprint
THE CHALLENGE
A hospital expansion with extreme subsurface
conditions:
- Parking structure extending ~20 feet into the underground La Cienega River
- Significant water intrusion risk
- Methane code requirements mandating:
- Permanent dewatering + filtration system
- Full methane mitigation membrane + venting system
Translation: High complexity + very high cost
SOLUTION
Terra-Petra didn’t just design the required system —they challenged the assumptions driving cost.
Key actions:
- Negotiated directly with LADBS to eliminate the requirement for a permanent dewatering system
- Redesigned the methane mitigation approach to meet code with a more efficient system
- Specified a dual-purpose membrane that functioned as both:
- Waterproofing system
- Methane soil gas barrier (agency-approved)
- Secured a 15-year, no-questions-asked waterproofing warranty
OUTCOME
- Eliminated a major capital and long-term maintenance cost (permanent dewatering system)
- Achieved full regulatory approval with a more efficient methane system
- Reduced system redundancy by combining waterproofing + vapor barrier
- Delivered long-term protection backed by a 15-year warranty
THE TAKEAWAY
Terra-Petra’s experience and deep understanding of the requirements and available materials allowed them to navigate, challenge, and optimize within the code – without compromising safety.
That’s real expertise showing up.