The plan is to build a shop this summer and I was asked what kind of insulation I’m going with.
I said I don’t know yet.

The guy recommended dense pack cellulose insulation. He listed a bunch of reasons why it was good.

Anyone here have any experience with it and have any advice whether it’s something I should consider?

Are you talking about the type where reinforced plastic is lip stitched on the wall then the cellulose is pushed in behind it? If so then yes I don't have any pictures right now but it is very good stuff, with studs on 24 inch centers you'll want to make sure and cover it right away or it will push out and you can't get the wall covering to meet the studs without serious persuasion.

Yes that’s the stuff! Good to know about getting the drywall on right aways, good tip! Thanks

I have built home with both dense pack and wet cellulose. Im a fan of the latter because you “broom” the excess off the face of the studs and dont have a problem with rock not wanting to marry to the studs. It also wont settle in a stud bay cavity as well as its more obvious when the monkeys are installing it wether a bay is full or bot. Sometimes they can overlook stuff when the mesh is up. That said, if installed correctly its great.

With the wet does it get dry and fall out?

No it has some sort of adhesive agent. Sort of sets up and will dry. It will be proud of the studs and they have a tool sort of like a wide paint roller that brooms the studs. It essentially leaves the insulation flush with the studs. Its slick. I was part of building one of the first legit passive houses it MT. Our walls were close to 14” thick. We did three rounds of that in there because it can only be so deep per application Usually our double walls hit somewhere around 9”. Its good for that because again it doesnt settle. I dont know if blown in dense pack really does that but insulators rate up there with some of the worst caring trades. I hate chasing them around and showing them the voids behind the mesh. I thinks its fine, just had to be done right. Sometimes people care about there work, sometimes they don’t. Voids can cause problems obviously and in a cold climate like this if you miss something it will start a condensation problem.

I went with Tyvek on the outside under the metal and spray foam inside with OSB for the walls. Very tight and easy to heat with baseboard heat.

I’ve always done the work with the blow in but I can see the problem if people don’t pay attention, I’ve never been around the wet stuff but I wondered how that stuff worked now I know.