Installing 1-Gang Box in Wall w/ BIBs Insulation

[pgtr]

In the detached workshop they put up what is called BIBs (blown in batting) insulation - after wiring, they stapled a sheet-like material across the studs on exterior walls (including shop), then blew in insulation at the top filing up each cavity between studs.

When adding an old construction gang box after drywall - after cutting the rectangle in the drywall... should the BIBs sheet behind the drywall also be sliced? I presume so but thought I'd check and see if anybody might confirm that is common practice. (otherwise - the plastic box will push the sheet back forming an air pocket)

thanks

 

[Zeke]

My question is how did you fish wire to the box? I presume in front of the membrane.
Also, can you determine whether existing boxes had the membrane cut?

 

[readhead]

The only purpose for the mesh was to contain the insulation during installation. You can cut anywhere you want.