Most attics are dry plywood is a smart vapor retarder with variable permeance.
Plywood in attic over insulation.
Make sure you don t block the air flow from the soffits.
That s clearly your plan if any moisture makes its way to the plywood the damp plywood will dry out on hot sunny days.
In most houses getting a 4 by 8 sheet of plywood into the attic is nearly impossible without cutting a bigger hole in the ceiling.
Wear long sleeves and pants since fiberglass insulation irritates.
If you can do it there really are no down sides except the.
What you could do is you could put insulation down in the floor joist first then plywood over it and then you could add another layer of unfaced on top of that.
Your plywood will be fine especially if you are paying attention to airtightness when you build your ceiling.
If necessary block around them with plywood or corrugated cardboard to prevent the insulation from piling up on the vent.
But you know i would rather see you just sort of map out the area in the center of the attic that you re going to use for storage and fill up the rest with insulation because that s the way you re going to get the most energy efficiency.
Walk to one end of the attic by carefully stepping only on the wooden ceiling joists.
It s not a vapor barrier.
Leaving part at r 19 is fine the rest will still be beneficial.
Put on work gloves safety glasses and a dust mask before entering the attic.
If you lay plywood and it squishes and compacts your.
How to lay attic flooring on top of fiberglass insulation.