[Ted White]

This comes up from time to time so I thought I'd post some data.

http://irc.nrc-cnrc.gc.ca/pubs/fulltext/ir766/ir766.pdf Courtesy of the NRC in Canada

Note that there's not much performance gain after R19

 

[68sting]

I' not smart enought to know what I'm looking at so I'll just ask the stupid question. I have some insulation left over and wondered if putting some scraps in the floor joists over the rec. room will have any effect?

 

[Ted White]

Certainly not a bad question at all. Since it's scrap and there's no possible harm, why not?

 

[adam r]

This comes up from time to time so I thought I'd post some data.

http://irc.nrc-cnrc.gc.ca/pubs/fulltext/ir766/ir766.pdf Courtesy of the NRC in Canada

Note that there's not much performance gain after R19

what about mineral wool or another insulation that is meant for sound deadening.

 

[Ted White]

They won't work better than simple fiberglass. Similar density fibers all work very similarly, so go for the cheapest.

 

[adam r]

music to my ears

 

[Mr.Guvernment]

They won't work better than simple fiberglass. Similar density fibers all work very similarly, so go for the cheapest.

Yes, totally bringing up an old thread but been doing a lot of reading. Good point, while Rockwool is being marketed as sound dampening, numerous studies are showing there is almost no to very little difference from using normal pink insulation, the main difference being cost, with Rockwool being almost double the cost in some cases per sq/ft. Finding this out just cut back a few hundred $$ potentially from doing my basement.

 

[BIGmouthinDC]

Roxul is heavier (more mass) than fiberglass. In a standard residential wall built with 2x4s and a single layer of ultra lightweight drywall on both sides that increase in mass probably makes a measurable difference hence the marketing claims. In a robust home theater project with two or three layers of dense damped 5/8 drywall hung on an isolation system. the difference between fiberglass and Roxul is insignificant. I like using some of the dense 4 inch Roxul boards (Safe) to plug major gaps