New construction Wall Insulation: Blown Rock Wool, Blown Fiberglass, Open Cell Foam

Blown anything for above ground walls will give you a better product than sprayfoam, IMO. Spray foam has the worst sound attenuation of all the insulation options and sprayfoam doesn't really have much if any payback compared to blow-in options.

I have BIBs in my house (blown in blanket fiberglass). No real complaints. Much better than batt insulation.

I only wish I would have went blown cellulose. Is there a reason you aren't considering cellulose?

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i was under the impression that rock wool and fiberglass were both better than cellulose. Issues i've been told with cellulose is that it settles. is there any fire retardency with cellulose?

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A couple answers:

- Better than cellulose? Not sure any one is specifically better. Cellulose will have better infiltration reduction than fiberglass, not sure on rock wool but it is probably cheaper than rock wool. Cellulose is a lot quieter than fiberglass, not sure on rock wool.
- settling: All blown insulation can have settling problems IF it is not installed properly. All blown insulation needs to be "dense packed." This means the blown insulation needs to be packed to the point its density is greater than the settling density. If any blown insulation is not packed above settling density, it will settle. If it is blown to a density higher, it cannot settle.
- Fire retardation: Cellulose is a better fire retardant than fiberglass. I'm not sure on rock wool but I would think rock wool might be better fire retardant than cellulose. There are some great videos on youtube comparing fire tests of cellulose and fiberglass. Fiberglass goes up like a tinderbox.
- Pests: Cellulose has better pest repelling capabilities than fiberglass. Not sure on rock wool.

Cellulose is a nice heavy final installation setup in walls. It reduces infiltration to very low levels. If you go any lower you have to get into HRV/ERVs.

I need to look more into rock wool. When I was looking into things for my house build, I never once ran across blown rock wool. I know rock wool makes a very good insulation, especially when considering sound. I used it in my basement ceiling. But that is all I know about it.

I will be building within the year and have gone back and forth on spray foam and blown cellulose.

I couldn’t find anyone to do the blown cellulose. I went with open cell foam and have been very happy with it.

Rock Wool is very good and would be my first choice.

Rock Wool > Foam > Fiberglass

size of house and price to do the job?

We used blown rock wool and it has worked incredibly. Our house is around 2800 living (I know, I’m OT poor) and our electricity bill is around $150 per month.
Why cant he find it from a different supplier?