Thornton, CO

Thornton Natatorium


The Thorton recreation complex includes a gymnasium, racket ball court, and a natatorium with two large pools and spa. The north masonry exterior wall of the natatorium was experiencing severe efflorescence and while the relative humidity in the natatorium was low, condensation was occurring in the exterior walls. SGH investigated the cause of the building enclosure issues.

Highlights of SGH’s work on this project include the following:

  • Performed water testing to recreate leaks and disassembled roof and wall sections to understand the construction details
  • Concluded that deficiencies in the natatorium roof air barrier and seal allowed moist pool air to flow into the cavity of the brick masonry wall and through the roofing causing mildew growth within the roof system, which is composed of asphalt shingles in sloped areas and a ballasted rubber membrane in flat areas
  • Designed new roof system with a structural air/vapor barrier, thermally broken structural blocking, and venting for a cavity space under shingles
  • Determined that deficiencies in air barrier construction and in the various mechanical systems caused a positive air pressure condition that contributed to moisture problems
  • Prepared plans and specifications for repairs and provided full-time monitoring during construction
  • Provided technical support to the owner to assist in recovering damages

Project Summary



Completion Date
Repair & Rehabilitation
Building Enclosures | Applied Science & Research
Culture & Entertainment
City of Thornton, CO
Specialized Capabilities
Building Science | Roofing & Waterproofing | Environmental Simulations

Key team members

Peter  Nelson
Peter Nelson
Senior Principal
Edward Lyon
Edward Lyon
Consulting Technical Director