Using ZIP System for a REMOTE designed house
The REMOTE system uses the “perfect wall” concept (Insulation outside the sheathing), but uses a rather conventional vented attic. The unconventional aspect of the attic is that it is incredibly sealed.
We are designing a REMOTE Passive House for central Ohio, and I would like your opinion concerning how to make that sealed ceiling.
One could use the Grace Ice and water shield on a plywood ceiling. I have concerns about that because I will have to design in areas of dropped ceilings to allow for utilities, and I believe that the Grace product will become detached over time.
Another possibility might be taped ZIP System. The much lighter weight of the tape might help keep it in place as it hangs on the underside. On a similar note, a liquid applied flashing to the entire underside of the plywood would eliminate all tapes. Both these ideas have one significant flaw – these are vapour permeable. REMOTE wants a vapour retarder, but then they use 6 ml Polyethylene, a barrier (like I used in my former residence in Edmonton AB) in their manual.
I plan to put 16″ wide strips of sealed and taped plywood on all the cap plates before the trusses are installed. I will follow up with bigger sheets to fill in the field afterward.
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