Push the knee wall firmly into place.
How to build a attic knee wall.
Mark the line that the angle forms along your 2x4.
Install insulation without misalignments compressions gaps or voids in all knee wall cavities.
But you do so at the expense of floor space.
Measure and mark the rafters at each end of the attic with the desired height of the knee wall.
Step 1 measure the attic to build your walls to the correct length measure the angle of the rafter by laying a piece of 2x4 inch lumber against the side of the rafter in a vertical position.
Do the same thing for the angled top of your knee wall nailing it into the rafters in three or four places.
Use your saw to cut along this line.
A knee wall is a short vertical wall roughly two or three feet high that blocks in that useless triangular space.
Install a top and bottom plate or blocking at the top and bottom of all knee wall cavities.
Install an air barrier on the exterior of attic knee wall insulation and to block open floor joist cavities under attic knee walls.
Nail down the sole plate the bottom of the wall in three or four places into the attic floor.