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REMOTE: Drainage cavity between insulation and exterior membrane?

ml22 | Posted in Energy Efficiency and Durability on

The REMOTE Manual does not indicate that a drainage cavity is needed between the rigid insulation and the exterior membrane. Lstiburek’s “The Perfect Wall” article, which is a similar assembly (or the same?) does not suggest this either. Has anything surfaced in the last few years to suggest a cavity is needed between these layers?

I’m in zone 4A, planning to use foil-faced polyiso. I have not selected the membrane yet.

I’m also planning to seal the polyiso on the outside face, hoping to keep most water on the surface and let the membrane act only as back-up. Innie windows means I’ll need to direct water outwards, with more flashing to the membrane as back-up.

I will use treated 1×4 furring to create a rain screen cavity.

Thank you.

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  1. GBA Editor
    Martin Holladay | | #1

    In the REMOTE manual, the drawings refer to the "exterior membrane" -- a layer that most people call a water-resistive barrier (WRB). In the REMOTE system, this WRB is often a peel-and-stick membrane that also functions as an air barrier.

    You don't want an air gap between the WRB and the foam insulation, because air movement at this location would rob your building of heat and would undermine the performance of your insulation layer. The proper location for a drainage cavity is between the insulation and the siding; your 1x4 furring strips will create a drainage cavity, so you are all set.

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