Why do they make water roll off rockwool?

[Hobby_Man22]

Personally I suppose it's a good thing mold wise, but I think it creates a lot of condensation issues that wouldn't exist with regular fiberglass insulation. Fiberglass would just absorb it. Now with that being said, in the south does that mean all these buildings with insulation directly up against the roof is probably a moldy mess? On houses the insulation stays in the rafters and then the entire attic is just vented through the roof eve and brought in through the soffit vents . This is why I didn't install a vapor barrier because they claimed its "optional"

Opinions?

 

[mike93lx]

Why would absorbing water be beneficial?

 

[Hobby_Man22]

Why would absorbing water be beneficial?

It's not but how long has fiberglass insulation done it? Since the dawn of time?

 

[mike93lx]

It's not but how long has fiberglass insulation done it? Since the dawn of time?

What relevance does that have? How it's always been done doesn't make it good.

I dont want my insulation holding moisture

 

[acer66]

Since they are competing with fiberglass they are just showing how mineral wool acts different to fiberglass.

Fiberglass tends to hold moisture/water which is not good.

Little amount is not that problematic but once fiberglass starts sagging you loose the r value and if staying soggy can promote mold.

 

[fitter30]

Rock wool is basalt rock and recycled slag and melted.