I recently ordered kraft faced R19 batts and FSKF-10 radiant barrier insulation foils (http://www.jkinsulation.com/materials1/view_all.nhtml ). The idea is to install the batts between the rafters with the kraft side facing down and then nail the radiant barrier foil on the underside of the rafters to cover the batts. The foil will then act as the vapor barrier.
Someone then told me that by having both the foil and the kraft paper batts, I will be creating 2 layers of vapor barriers and this is not a good idea due to the possibility of condensation between the barriers.
Should I use unfaced batts instead so that I only have 1 vapor barrier (ie the foil)?
There is actually no cost difference to me. Either going with faced or unfaced batts is OK with me.
By the way, I do have HVAC in the warehouse, which is operated only when the warehouse has people in it.
Please advice... thanks!