I have a 115 yr + 2 story old house. As a spring project I took up some of the double floor boards in the attic thinking I would check and if needed, add more insulation. I have joist 3x5, 24in space between the joists. The depth is 7” total, to the lathes and plaster with 1” of rock wool insulation all ready there.
1 My question is do I need to clean out the old insulations, then place a vapor barrier down in the cavities then blow in the new insulation ?
2 Do I need the vapor barrier? Or can I blow more insulation in what is all ready there?
3 I’m going to place 2x8 on its end on top of the existing joist to add heights to 14” thick of insulation. These 2x8 r going to be integrated into the existing timbers to add strength
Hoping that I don’t bow the 3x5 joist and knocking the plaster off the ceiling.
4 As well could I use vapor barrier paint in the rooms below on the ceilings instead of the vapor barrier in the attic?
Then place the double floor boards back over so I don’t lose the storage space.
Thanks for any info . Hamm8 , Nova Scotia