# Wet Mineral Wool



## rightit (Mar 5, 2011)

I picked up 300 sq ft of mineral wool today. Unfortunately, I got caught in a downpour and the bags were not sealed. Consequently, some of it got pretty wet and seemed to be holding the water. I got it back to my shop and placed it wet side down (batts at a 45 degree angle, plastic open).

This is 1 1/2" sound attentuating MW, and I plan on using it on an inside wall. Googling turns up one source that states it: "...will provide a structure for bacterial growth if allowed to become wet".

Questions:

1. Will that be an issue if allowed to dry before placement?

2. How long will it take to dry?

Thanks!

Edit: I guess #2 is subjective. Also not as bad as I thought. I opened up the bags, squeezed the ends of 4 or 5 soaked bats (I can cut those ends off if it doesn't retain its shape after squeezing). I set up a few fans blowing at the wet ends of the bundles. #1 is still a question, however, since there seems to be some conflicting info on the net.


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## Gary in WA (Mar 11, 2009)

Mineral wool, or rock wool can get wet and retain it's insulating qualities after drying. Fiberglass, AFTER installed, can contain mold spores even when it looks like new. New f.g. doesn't contain mold spores. After drying, use a nose tissue or t.p. to test for wetness. http://www.inspectapedia.com/sickhouse/FiberglassMold.htm

http://www.roxul.com/stone+wool/faq#1034_1414

http://www.inspectapedia.com/interiors/Rock_Wool_Insulation.htm

Gary


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## rightit (Mar 5, 2011)

Hi Gary. Thanks for your response. I also thought that mineral wool (like Roxul) woulld not support mold growth. It's drying right now and I plan on installing it, but posted the thread because of this (and a few other) links. This link is the one I quoted the "bacterial growth" statement from:

http://en.wikipedia.org/wiki/Mineral_wool


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## AllanJ (Nov 24, 2007)

Depends on whether the rain water, or the outsides of the bags the rain water ran over, or the stud bays where the mineral wool will be installed, were contaminated with mold spores or organic matter to feed the mold with.

Once the insulation dries, any mold growth should be stopped or at least almost completely retarded.


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## rightit (Mar 5, 2011)

Hi Allan. That makes sense. Fan drying seems to have restored them to original condition. Also, I've sprayed the intended wall with Timbor and will spray again today and sprinkle some Timbor powder in the bottom of the stud cavities before installing. 

Thanks!


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## M3 Pete (May 10, 2011)

I was thinking that since mineral wool is completely inorganic, mold growth would be impossible. But according to wiki, they add some organic material.

"Mineral wool may contain a binder, often food grade starch, and an oil to reduce dusting."

But mold needs water, so a thorough drying should take care of it.


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## rightit (Mar 5, 2011)

M3 Pete said:


> I was thinking that since mineral wool is completely inorganic, mold growth would be impossible. But according to wiki, they add some organic material.
> 
> "Mineral wool may contain a binder, often food grade starch, and an oil to reduce dusting."
> 
> But mold needs water, so a thorough drying should take care of it.


 
Hi M3 Pete. It has indeed thourougly dried. And the fact that life has conspired to keep me from 'getting to it', it has spent several days in front of a shop fan and the last few days in the air conditioned space I'll be placing it in. That, on top of the Timbor solution, which also prohibits mold growth (_and Timbor _powder sprinkled on the bottom plate) _should_ suffice (thanks to PAbugman for that advice when I was discussing termite protection).


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