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northern 02-03-2010 10:34 AM

Thicker insulation in a thinner space?
Hey guys, we were wondering if it is ok to put, lets say a 9"-10" thick insulation in a 6" space? Is it ok to pack it down to make it fit in there? Are there any pros or cons to doing this?


travelover 02-03-2010 10:36 AM

It decreases the insulating performance to compress it. Don't do it!

GregC 02-03-2010 10:37 AM

Hello, No not a good idea. Insulation is made to work when it is "fluffed" in the space. Compacted or compressed insulation reduces the R-value rating. Always check manufacturers recommendations. ;)

northern 02-03-2010 11:40 AM

Good to know! Thanks very much for your help guys. Much appreciated.:)

GregC 02-03-2010 12:13 PM

No problem, you're welcome. If you are looking to gain more R-value, you can use Polystyrene hard foam in the cavity, then make up the different with fiberglass. Polystyrene hard foam comes in sizes from 1/2" all the way up to 2". This way you can place 2" foam board then 3-1/2" of fiberglass. This will fill a typical 2x6" wall. (5-1/2" cavity) and so on for floor joists etc. Hope this helps. Just a thought!;)

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