The Scenario
An apartment building with a flat black rubber roof. The A/C condenser is on a platform on the roof with an air handler inside the unit. The line set runs across the roof for about 20 feet before reaching the platform. The lines lay directly on the hot black rubber.

At a minimum I'm looking to insulate the coolant line. In the past I've used ArmaCell polyethylene pipe wrap, but it breaks down very quickly leaving the coolant line exposed, poorly insulated, and sweating. Are there better alternatives?

The ArmaCell insulation

I'm also considering elevating the line, even a few inches to reduce the heat transfer from the rubber roof. I keep thinking there has to be typical solution used by HVAC contractors, but I've yet to find one.

Any structure would need to be stable and provide good drainage. The best thing I can come up with is cable tray used to run Ethernet. Thoughts? Solutions?

  • 2
    I think you need exterior pipe insulation which has at least some type of UV protection. As well as pipe standoffs to hold the pipe above the surface of the roof. – Dan D. Jun 28 '13 at 16:30

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