Last week end we started on the window plug. For the window frame and sill the distance between back of OSB and the window studs = “IB-1 Clip + 7/8” Hat Track = 1 1/8” deep”. I framed the window by screwing a 2x2 ripped to 1" so 1 1/2" x 1" to the OSB/DW insuring I did not touch the window studs. This left a 1/8” gap which I filled with acoustical caulk. I used the pink insulation strip around the window studs and then attached ¾ inch MDF with screws to the 2x2 leaving 1/8” from window casing then added some acoustical caulk.
This is the before picture. Make sure when you do the hat channel you leave enough space on the channels that terminate at the window for the 2x2 so back them 2” away from edge of window stud.
Here you can see the 1 1/8" gap between the OSB and window stud.
Here you see the pink insulation strips you can almost make out the ripped 2x2 on back side of OSB and drywall.
Here is the after with the plug setting on the sill. I did not put a conventional window sill and frame as I know that there would be a window plug. The sill is the same construction 2x2 internal and MDF. You can see the MDF sits flush with the drywall. Use some more caulk here as well. I took some really careful measurements cutting the OSB and drywall because you want the drywall and OSB opening to be 1/8" smaller than the window opening so the 2x2 once fastened to the back of the OSB is 1/6" inside the window stud. This gives enough space for the pink insulation strips.Edited by cw5billwade - 1/24/14 at 10:53am