Hi all. I'm finishing my partly unfinished attic, has HVAC and electrical, just needs insulation and drywall. I currently have 2x4 studs along the knee wall but was told by an insulation contractor that R21 was best for the walls and that I should replace the 2x4s with 2x6s which would accept the R21 insulation. My question is why replace the 2x4s? If I use craft faced insulation, which would get stapled to the studs, why would it matter if the insulation extended past the studs into the cavity behind it? I will be putting vents in the roof rafters and installing R30 there and R49 along the cross rafters (leaving a cavity between the ceiling and the ridge) to allow for proper air flow from soffit vents to ridge vents. Appreciated input on the knee wall conundrum.

Id like to move a lally column in the basement of my new construction one story house. There are 4 or 5 columns that run under the center beam all 8 feet apart. I believe i have confirmed the presence of a continuous footing under the columns by drilling a 1/4" hole between two columns and still hitting solid concrete at a depth of 7.5 inches. One of the lally columns lands center of the back of the stairwell and Id like to move this column over to use the underneath of the stairwell for storage. My plan was to add a column on each side of the stairwell as to not make that 8' span grow. I see various types of columns available, some being the screw jack type, others, like mine, i am assuming are a cut to fit and possibly even filled with concrete after install. Is this necessary and would i be fine with a screw type column or something else? As mentioned before i am replacing one column with two columns. Thoughts?