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Fiberglass vs Rock

810 Views 8 Replies 7 Participants Last post by  Greenlight1
I much prefer to use rock wool rather than fiberglass. It's easier to cut and seems to be safer as the fibers are going throughout the room. I cough when using fiberglass so I wear a mask, I don't seem to need one when using rock wool.

On the internet, says, fiberglass is the #1 in the U.S. while rock wool is the go to insulation in Europe, why is that?
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I much prefer to use rock wool rather than fiberglass. It's easier to cut and seems to be safer as the fibers are going throughout the room. I cough when using fiberglass so I wear a mask, I don't seem to need one when using rock wool.

On the internet, says, fiberglass is the #1 in the U.S. while rock wool is the go to insulation in Europe, why is that?
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I prefer Rockwool too.

I thought the Rockwool was more expensive. It seemed to be when I did my attic. But I just checked, and rockwool vs fiberglass are pretty much the same.
With insulation neatness counts. Rock wool is easier to install neatly, tighter fit and ultimately better insulation.

The reason fiberglass is/was used more often was price.

It also reduces air flow through it.

Bud
Newer fiberglass insulation is nicer to use than the old kind. Still should wear a mask with it, but I don't consider it all that different from mineral wool.

I think mineral wool is more annoying to install. Newer fb holds its shape well enough yet is more flexible than mineral wool, is lighter than mineral wool, and gives more margin of error in tricky areas.

Even cutting them... "MW is like cutting a loaf of bread." True. But FB only takes one quick slice to cut.

I consider MW a better product overall, mainly due to its better rodent and moisture resistance, but MW isn't that much better, and both are great at being fire-resistant.

MW is usually around twice the price of FB here, which isn't terrible, but FB can get much cheaper during special sales. Maybe it's the catch-22 of if MW was more popular there would be more quantities of it and they would go on sale more.
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FM3, have you ever tested a wall assembly with mineral wool vs one with FBs with an infrared camera. Energy auditing has ratings for the quality of performance for insulation and the MW walls I have inspected looked great. FB can look good so the difference may come down to how careful the installers are.

Frankly, some installation crews I have seen, speed is the only guideline and they know the drywall will be up immediately behind them and they don't like infrared inspections because their sloppy work can't hide.

Added note, boy have I seen some sloppy fiberglass work.

Bud
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FM3, have you ever tested a wall assembly with mineral wool vs one with FBs with an infrared camera.
Not lately.

Based on the OP's post and this being a DIY site, I did write my post assuming the installer actually cares about the finished result.
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I much prefer to use rock wool rather than fiberglass. It's easier to cut and seems to be safer as the fibers are going throughout the room. I cough when using fiberglass so I wear a mask, I don't seem to need one when using rock wool.

On the internet, says, fiberglass is the #1 in the U.S. while rock wool is the go to insulation in Europe, why is that?
I think what the internet means is "fiberglass is the /cheapest/ in the U.S." [and thus #1 with developers] :vs_laugh:
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I have used Roxul brand “safe N sound” before and really liked it. It is around $48-$50 per bag at Orange store which was around 35-40% more than FG rolls. It recently went under the Buy in Bulk category when buying 16 or more rolls you saved 25% so at that point it was a no brainer. Roxul makes a quality product that I feel has several advantages over FG especially when installed in a damp environment.
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