When and how are you going to insulate?

The plan is to put the concrete board on the wall up to the dropped ceiling. Above that it'll be covered in insulation mesh. Then I'm having a guy come in and blow cellulose into the wall. I guess I might have to throw the drywall on top of it right away too. The concrete board is an odd size, 5'x3' so it doesn't really hit board centers all that great. Anybody know why?

I don't know why myself but it is a good question. It's for use on walls.
Is there a particular reason why you are not blowing behind netting? It's clear as day that when you blow behind netting you do a better job because you can kick the tires, so to speak. When blowing behind a wall of some kind you don't know where the soft spots are and you couldn't do anything about them even if you knew where they were.

That decision was based off what the insulation blower wanted to do. He didn't seem confident the mesh would hold up to the pressure. I tried to assure him that that is what it is made for and I've seen it done (online). I could have him blow behind mesh and I might talk him into it with the cracks and crevices that are in this wall. I'd feel better if I could see and feel how well things were going.

Are you set on this contractor? It is standard practice to blow behind netting. That's the SOLE purpose of Insulweb. Net and blow is the default method for new construction simply because you can see what's happening. Even with a machine with a dual blower you won't blow the netting out. You could make a hammock out of the stuff. One layer of it. I do this all the time. I did an 8" wall the other day. I have done 12' and 14" walls with netting and the absolute most powerful double blower machines on the market. The only catch with a really powerful blower is that you've gotta be vigilant to not clog the hose. If you let it back up for too long you can quite literally dense pack 100' of hose. Then you're screwed. Nothing anyone with a little experience can't avoid. If you can rent a good machine and hook up a webcam with Skype or something I'll help you do it yourself. It's not difficult but it really does take some guidance at first. He probably only really has experience with drill 'n fill style dense packing, which is a sub optimal method. I have done this for, probably, thousands of bays and still when I fill a test box or test bay I don't do as good a job as when I blow behind netting. There are always some soft spots. Maybe it all equals out in the end because some parts are more than 3.5 Lbs. / ". I don't know. But all I can say is that after several months of drill 'n fill style blowing, the first time I blew behind netting I was shocked by all the voids. I mentioned to my co worker/teacher how this method is vastly superior to the drill 'n fill. All he had to say was "Oooohhhhh yeah". He'd worked as a cellulose blower exclusively for years. He's much better/faster than me and knows the score.

I wish you lived closer. I'd do it for you and show you how in the process.

I believe that concrete board is smaller due to weight. 3x5 I'd assume has to do with around tubs? The surround on my tub is 5' long by just under 3' wide. and 5' tall all the way around.

Yes sir. But neither 3' or 5' makes sense with 16" or 24" O/C studs. It's a quandry for sure.

Thanks S-F. I'll talk to the guy. I'm pretty sure I can convince him to blow behind the mesh.

BTW, how do you recommend fixing it to the wall, staples? I hear they must be closely spaced?

You hang it with a T50 stapler making sure to stretch it tight and flat. Then you side staple to the studs with an air stapler. It's like a machine gun and can blow through thousands of staples an hour. Don't face staple to the stud or the bay will bulge out so much it will be hard to get the sheet rock on, even after rolling it. Staple the netting to the sides of the studs. You could do it with a T50 if you had enough time. I've done it, one day when two machine guns died on me and I had not other choice. Any installer should have a staple machine gun though. Putting up the netting is part of the bid.

Rolling: Usually done by the rockers is a process were a pole with a roller at the end is run up and down the bulging bay to flatten it for the installation of sheetrock. You know the stands for a table saw that have a roller on the top to allow lumber to remain at the level of the table but still move freely? Same thing. In fact I often use one of them for rolling cellulose. You could probably also just use a rolling pin.

Alright, Let me just verify. You wrap the mesh around the side of the stud ~1/4" and then staple it?