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drainplane on inside or outside of 4″ exterior rigid on conc foundation wall?

jreilly17 | Posted in Energy Efficiency and Durability on

I’m designing a finished basement in a marine climate. Thermal insulation will be 4″ of rigid on the outside of the concrete foundation wall. Given that the drainplane wants to protect the concrete most importantly, but also given that any ground-water is likely to encounter the rigid first if it is on the outside- where would you put the drainplain? inside or outside the rigid?
Thanks to everyone,

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  1. GBA Editor
    Martin Holladay | | #1

    What product will you be using to provide a "drainplane"? I assume you are talking about some type of three-dimensional plastic mesh, protected with landscaping fabric so that the air spaces aren't filled up by silt.

    I would place such a product outside of the foam, so that the R-value of the foam is not separated from the concrete.

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