Holding back cellulose
I’m just about done air sealing our attic and getting ready to blow in cellulose. For a few sections I need to make a vertical “wall” of it. One part is where the stairs are. As discussed in another thread part is a flat ceiling, then a vertical slope down to the stair ceiling. I’m going to put fiberglass batts on the vertical sections, but want to blow in cellulose on the flat part. I’m thinking of stapling window screening to the top plate of the actual wall and then staple it to the ridge beam of the house. This will get me a vertical wall, but will it (1) hold back cellulose with the little holes and (2) stay stapled. The area is probably 12 inches high.
In the other section I need to separate the part of the attic that will just have insulation, and the part I haven’t touched yet that has storage. I’m thinking 1/2 plywood standing up vertical with some 2×4 supports should hold it back.
These are small sections, google keeps finding me netting used for walls, this won’t be covered up and I don’t need a big roll of something either. Thoughts on both appreciated!
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Jeremy,
Vertical components are called walls or kneewalls. They are usually built with studs (2x4s or 2x6s) and sheathing (plywood, OSB, or rigid foam), but you can improvise if you want.
Polypropylene blowing meshes used by the insulation pros aren't very different from weed-control landscaping fabric, which is cheap and comes in 3' or 4' wide rolls, easy to find at box stores in small quantities. A 3' x 50' roll of propylene landscape fabric can be had for $10 from the big blue or orange box stores.
Just be sure to staple it at least every 2" onto the framing (some of the pros even use wood glue applied with a roller after stapling) to prevent the mesh from detaching. This works at any angle, even vertical.
When it's time to blow behind the mesh, slit the mesh just enough to insert the hose, and push the hose to within a foot of one end of the framing bay, then blow insulation until the blower begins to stall, back it out 8"-12" until it stalls again, repeat. Then push the hose as far as you can toward the other end, blow/stall/repeat. With a 1-stage rental blower you can get about 2.5lbs density out of it that way, without having to fabricate up some dense-packing hoses.
Thanks both of you. I have both landscape fabric and window screen leftovers. My concern with landscape fabric was it tearing, my concern with window screen being the little holes. I should be able to blow around each and back up as I go, without making any holes in it. Maybe I'll just both, I don't want to realize from afar a few years from not that it's failed and the cellulose has fallen from where I want it.
As for the dam between storage and just lots of cellulose, I'm planning to go with 1/2 inch ply or OSB.
Landcape fabric is usually a bit more rugged/heavier than blowing mesh- it definitely won't tear on you, which is why it can be used under crushed rock and other sharp-ish materials and still go the distance.
I've read of people stripping the polypropylene off the bottom of the box-spring of beds when they needed just a few feet of blowing mesh, but I can't recommend it. :-)