Hillwood Properties GW50 building is a large distribution building located in Roanoke, Texas. Over the past few years all of the non-refrigerated areas have been replaced as an ongoing maintenance program. The recently completed project was to complete this replacement program on the remaining areas. The project consisted of removing the existing ballast rock, removal and disposal of the existing EPDM membrane and replacement of any damaged / wet polyisocyanurate insulation. The majority of the project was over the refrigerated / freezer section of the facility and the Air conditioning penthouses which contain the cooling equipment. The roof has an extensive amount of ammonia piping and associated supports which proved to be a challenge in material handling, flashing and personnel access.
As the ballast and removal began, we ran into large areas where the polyisocyanurate insulation was actually frozen solid and pick axes, roof cutters and chain saws were utilized to remove the frozen insulation. As typically is the case is recover ballasted jobs none of these tools are required as the existing damaged or wet insulation is simply lifted off the roof deck and placed in dumpsters. A typical 2’X2’ piece of polyiso insulation will weigh less than a pound. Supreme Systems were removing the same size pieces of insulation and they would weigh in excess of 10 pounds. Needless to say this poised several logistics, production and dumpster challenges.
Before proceeding any further, Conley Group and Supreme Systems took numerous core samples to determine 1) What is the extent of this anomaly? 2) What is the cause of this anomaly? 3) What is solution to ensure this doesn’t occur in the future?
The core sampling revealed that the original design did not provide for a continuous vapor barrier and a complete lack of a vapor barrier at the roof perimeters, expansions joints and penetrations. With interior temperatures ranging from 22 degrees F to -35 degrees F a continuous vapor barrier is required to prevent condensation within the roof system as well as the building interior.
Conley Group and Supreme Systems worked together to develop details that would not only provide the proper vapor barrier details but also ensure the end product would provide for a long lasting watertight roof assembly.
The project turned out to be a complete success and will save the owner cooling costs over the term of the new installation by preventing the excessive air leakage into the new roof system. Overall the project was 295,000 sf, 15 roof areas and $1.62 million in construction cost.
Conley Group, Inc.
5800 E. Campus Circle, Ste 250
Irving, Texas 75063
Phone: 972.444.9020 Fax: 972.444.9737