Attic catwalk with minimal thermal bridging
I’m planning to add 12″ of Rockwool batts over 2×4 ceiling joists (there’s already cellulose between the joists), and looking for some creative ideas for building a catwalk with minimal thermal bridging. The usual design involves a lot of 2x4s sitting on top of the joists and sticking up to support the walkway, creating numerous thermal bridges through the ceiling.
I’m wondering if the 12″ of Rockwool batts would be enough to spread the load of 5/8″ plywood simply laid over it (plus a person walking) without crushing the batts. There is also an interior partition wall that runs directly under the center of where the walkway would be. If not, perhaps Foamglas instead of Rockwool under the plywood?