Union Subcontractors for Environmental Mitigation & Building Envelope Waterproofing Systems; specializing in vapor intrusion, methane mitigation and building envelope waterproofing systems Lic# 881201. Locations: • 519 N. Fairview Street Santa Ana CA 92706 • 895 San Leandro Boulevard San Leandro CA 94577 Small Business Enterprise Certification# 2004112 Specialties: • Vapor Intrusion Mitigation Design & Construction. • Construction Management. • Waterproofing Building Envelope Design & Construction. • Estimating & Project Management. • Business Development.