The distance between knee wall and attic ceiling is about 6 foot. Could I push a perforated pipe between the rafters?
That is an option. And there aren't many options.Not much is going to slide easily behind the insulation. I'm thinking --------------------. You are undoubtedly going to snag on roof nails coming through the decking. I don't know if they would hold up but the cardboard tubes wrapping paper comes on might work if you tape 2 together. and flatten and tape the end you will be pushing in first. cut slots with utility knife. I think your idea would work if you can afford the pipe. That's a tough one. When we convert attics we line those cavities with a styrofoam insulation chute end to end until we reach open ventilation-you probably know that by now. Give it a try.
