Monopoly Roof Assembly on Existing Home: Is it actually done? – GreenBuildingAdvisor

Knowing that our vaulted ceilings were at risk of rotting from the inside out, I’ve tried several times over the years to find a contractor who will retrofit our roof deck with rigid foam insulation.  Time has run out, and we need this done now.  

Thanks to GBA and other sources such as ASIRI designs, I know this can be done and is currently being done in new home construction.  But I’ve also seen it recommended for retrofits, especially on the ASIRI design website.  Christi Weber even wrote about it this spring.

https://www.greenbuildingadvisor.com/article/monopoly-roof-assembly-with-nail-base-panels

But I’m still running into dead-ends here in Tacoma, Washington/PNW.  What is the magic word to find that unicorn contractor?  Is this actually done in the real world?