Attaching Roxul (Comfortboard 80) to exterior foundation wall
My wife and I are building a “green” home (mix of Passive House, Pretty Good House, and Net Zero). For the basement foundation (9′ basement) we intend to use spray-on waterproofing then two layers of Roxul Comfortboard 80 mineral wool (3″ + 2″ = 5″ total) on the exterior side.
Initially we thought we would use the Ramset system of fasteners to attach the Roxul to the foundation, but it’s pretty clear that waiting at least 28 days after the foundation pour would be necessary (per manufacturer’s recommendations and opinions found in online searches) to avoid potential damage to the concrete wall. Obviously we would like to avoid this delay if at all possible.
What are sensible alternatives? Pre-drill through Roxul and then use Tapcon fasteners?
In addition, in a belt-and-suspenders approach, does it make sense to then add a dimple membrane layer to the outside of the Roxul? Presumably this is an insurance policy against water making its way through the Roxul and finding space around the fasteners to enter the concrete wall? In a Hammer and Hand video it looked like they incorporated this approach.
Any other cost-effective way to achieve this? Instead of dimple membrane, what about using 10 mil Stego wrap?
Thanks ahead of time for any suggestions or answers. GBA is a resource we go back to again and again to find effective answers to our endless questions.
Thanks so much,
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