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Insulation

2K views 10 replies 7 participants last post by  piste 
#1 ·
I have insulation blown into my attic and I want to put flooring down. But I read that the blown insulation should not be compressed. It is piled up above the joists. I dont want to remove it and replace it with another type of insulation if I dont have to and I cant raise the flooring to above the current insulation without compressing it. Is there a solution?
 
#8 ·
Run some 1 by or 2 by material perpendicular to your existing joists and put your floor on that. I assume you don't need the entire attic floored. If you want another 8 inches of insulation, lay down 8 inch stock on 16 or 24 inch centers. Fill the area with insulation and then put the flooring down. Thats what I'm getting ready to do. Hope that makes sense.
 
#3 ·
The first thing you need to do is define your framimg up in the attic. Is it trusses or stick framed?
Take a picture if you're not sure.
Ron
 
#5 ·
You'll need to decide which is more important. Storing items or the insulation. You can't have both without building up the floor to a height above the insulation.
I disagree with Bob about moving the insulation up to the roof rafters as a solution as the warmth from below will just get into the attic space when you want it in the rooms below for as long as possible.
Using a foam insulation in the joist bays will give you both options, floor and insulation value. but that would be a significant expense as the blown in stuff would need to be removed as well as the cost of the foam.
Ron
 
#6 ·
I could do that Bob which would eliminate the concern about the blown insulation on the floor but I didnt want to go to that expense at this time. The floor is for storage of things that dont need temp controlled. But if compressing the floor insulation affects the integrity of the blown insulation then I will have insulate the roof.
 
#9 ·
If you go that route, be sure to run the new joists with the old, to elevate them on proper bearing walls below, creating a thermal break from the old joists and not over-loading them. They are only ceiling joists, rated to carry 10 or 20# live load per foot. Plaster weighs 8# per inch, per square foot. 2x8 joists weigh 2.2# per square foot, 2x10- 2.9# at 16"o.c. Older houses are notorious for longer than safe spans, not to add more weight. Cellulose weighs .14# per inch x 12" = 1.68# times your on center spacing, 16" or 24". If joists are 2' o.c. and 1/2" drywall, it is not recommended for cellulose. http://www.energyguide.com/library/EnergyLibraryTopic.asp?bid=austin&prd=10&TID=17324&SubjectID=8375

Be safe, Gary
 
#10 ·
thanks Ron. I think what you are saying is that IF I put flooring over the blown insulation, compressing between the joists it will compromise the insulation and heat will escape to the attic. So if I want flooring I need to replace the insulation under the flooring. Right?

DAve - the insulation is about 2-3 inches above the joists.

Mike - My attic roof is too low to raise the flooring at all. I cant stand up now.

Gary - thanks for the info....I have been concerned about weight so I get your point too.

thanks guys.
 
#11 ·
I'd go with Mike's recommendation...lay down some 2x4's then the flooring. Being as insul is now 2 to 3 inches above current joists...you'd only be compressing it less than two inches. the insulation value lost with that compression will be somewhat...at least slightly offset by the added flooring creating an barrier above the insulation. You could even just add the flooring without the 2x4's IMO...but the 2x4's are easy and inexpensive and help preserve the insul characteristics. That's the way I'd go. good luck.
 
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