Case Study: A Public School in Michigan

Clearing the Way for Coating

A public school roof in central Michigan, was scheduled to be resealed with a liquid applied coating.  Two adjacent roof sections were involved separated by a parapet wall over which line sets needed to pass.   Prior to coating  five mini splits using 4”X 6” wood sleepers were mechanically fastened to the roof deck as well as a condenser unit mounted on 6” X6” sleepers.  Seams were coated with a sealant, but upon inspection, roofing manufacturer’s technical representatives believed that the installation as it was might invite roof leaks under the sleepers:  the sealant was applied only around the perimeter of the wood sleepers—none was applied underneath.  The roofing manufacturer requested that the sleepers be removed and that KnuckleHead supports replace them to ensure there would be no leaks. The wood sleepers and screws were removed, the holes were filled with GreenLink Adhesive/Sealant, and the units remounted on KnuckleHeads. allowing the coating to be applied fully.   A range of KnuckleHead products were used:  Strut frame mechanical supports to replace the sleepers, Pavers for the condenser, and Heavy and Lite Pipe KnuckleHeads for line sets.

With the seams sealed and the mini splits mounted on 4’ X6’ wood sleepers, the coating was ready for application.  But roof technicians were concerned that the coating could not be applied under the sleepers, creating a potential avenue for leaks.

The wood sleepers were removed and replaced with a KnuckleHead Strut frame system.  Strut KnuckleHeads were attached to the roof deck and sealed with GreenLink Adhesive/Sealant.  Then steel channel was set into the strut heads and bolted in place to form the support frame for the mini split.

Line sets originally ran from the mini splits over a parapet wall to the adjacent roof surface, as seen here.

The line sets draped over the parapet wall photo were left dangling off the roof surface without support.   Freestanding Heavy Pipe KnuckleHeads with extensions were used to elevate the sets approximately 8 inches off the surface.

Safety-yellow caps contained the line sets.

One of the six units installed was a condenser.  The original installation was set on 6” X 6” wood sleepers, which were placed on a vinyl slip sheet.  The slip sheet had deteriorated from ponding water and in turn had caused the sleepers to undergo rotting.

The sleepers that elevated the condenser were replaced with Paver KnuckleHeads, which were attached to the roof deck. Single condenser lines were supported by Lite Pipe KnuckleHeads.

Here a contractor attaches the Universal Base in preparation for installing a Paver KnuckleHead.

The electrical box was originally mounted on channel attached to the wood sleepers.  The same problem as the mini split installation was encountered here:  the inability to apply coating under the sleepers.

After the sleepers were removed, the electrical boxes were securely bolted to the KnuckleHead mechanical strut frames eliminating the risk of wood deterioration. GreenLink Adhesive/Sealant was applied under and around the KnuckleHead bases to prevent leaks.

A finished installation with the Strut KnuckleHead mechanical support system ready for the application of roof coating.