I’m planning radiant heat under the enclosed porch. My thought had been to run the heat and then put in insulation and skin the underside of the joists. Someone just mentioned that I should be careful doing that not to trap moisture. Theoretically I’d like to be able to get at the pex pipes if there’s ever a problem with the radiant heat, so I wasn’t planning foam. Are there any other choices that would allow me to seal the underside? Or would putting vents in the bays do anything? The floor is framed 2×8, 16″ oc and the porch is 9 feet off the ground. Currently there’s nothing under it, but I am planning on screening in the underside.

Thanks,