(206) 949-5683, Top Rated Plumber, Seattle
Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: Insulation in attic

  1. #1
    DIY Member Semon's Avatar
    Join Date
    Oct 2011
    Location
    Tn.
    Posts
    36

    Default Insulation in attic

    I need to put insulation in the attic. I want to bring it to about R30.
    Which is better Bats or blown?

  2. #2
    Homeowner
    Join Date
    Jan 2010
    Location
    Alabama
    Posts
    1,174
    Blog Entries
    1

    Default

    I used r30 batts then used 6" of blown over that.

  3. #3
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    Quote Originally Posted by Hackney plumbing View Post
    I used r30 batts then used 6" of blown over that.
    This ends up compressing the batts, and decreasing their contribution to the total insulation level. the batts must be fluffed to their design height to provide the specified insulation level and that doesn't happen when you pile stuff on top of it.

    Bang for the buck, blown cellulose is probably one of the better choices - it fills nooks and crannies and stops convective losses through air movement (if there is any). In an old install, a quick check for air infiltration with fiberglass batts is to look for discoloration...the fiberglass is acting like an air filter. WHen this happens, you lose a lot of the theoretical performance.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  4. #4
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,245

    Default

    Blown in is inexpensive both to buy and to install. I discovered years ago when I wanted to insulate my garage/shop attic. I could have bought the blow in from HD, and used their blower for free, but I learned it's not only a rather unpleasant task, it takes at least 2 people. One to direct the insulation coming out of the hose, and one on the ground to feed the blower. Then I check with a local insulation company, and found they would supply the material and do the whole job for the same price as I would have paid HD.

  5. #5
    DIY Senior Member dlarrivee's Avatar
    Join Date
    Jun 2009
    Location
    Canada
    Posts
    1,172

    Default

    Quote Originally Posted by Hackney plumbing View Post
    I used r30 batts then used 6" of blown over that.
    He asked for the best way, not one of the worst...

  6. #6
    DIY Senior Member dlarrivee's Avatar
    Join Date
    Jun 2009
    Location
    Canada
    Posts
    1,172

    Default

    Quote Originally Posted by Gary Swart View Post
    Blown in is inexpensive both to buy and to install. I discovered years ago when I wanted to insulate my garage/shop attic. I could have bought the blow in from HD, and used their blower for free, but I learned it's not only a rather unpleasant task, it takes at least 2 people. One to direct the insulation coming out of the hose, and one on the ground to feed the blower. Then I check with a local insulation company, and found they would supply the material and do the whole job for the same price as I would have paid HD.
    What was your first clue that it would take 2 people?

  7. #7
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,245

    Default

    Duh! Guess I was a slow learner. LOL Actually, I really knew it would take two and that I'd have to recruit an unsuspecting friend...maybe ply him with a few beers before springing the job on him.

  8. #8
    DIY Senior Member dlarrivee's Avatar
    Join Date
    Jun 2009
    Location
    Canada
    Posts
    1,172

    Default

    You could do it with one if you're a fast runner!

  9. #9
    Homeowner
    Join Date
    Jan 2010
    Location
    Alabama
    Posts
    1,174
    Blog Entries
    1

    Default

    Quote Originally Posted by jadnashua View Post
    This ends up compressing the batts, and decreasing their contribution to the total insulation level. the batts must be fluffed to their design height to provide the specified insulation level and that doesn't happen when you pile stuff on top of it.

    Bang for the buck, blown cellulose is probably one of the better choices - it fills nooks and crannies and stops convective losses through air movement (if there is any). In an old install, a quick check for air infiltration with fiberglass batts is to look for discoloration...the fiberglass is acting like an air filter. WHen this happens, you lose a lot of the theoretical performance.
    6" of blown didn't compress anything.

  10. #10
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    Quote Originally Posted by Hackney plumbing View Post
    6" of blown didn't compress anything.
    Have you measured recently? It can take awhile to compress. Or, your blown-in component wasn't very dense.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  11. #11
    Homeowner
    Join Date
    Jan 2010
    Location
    Alabama
    Posts
    1,174
    Blog Entries
    1

    Default

    Quote Originally Posted by jadnashua View Post
    Have you measured recently? It can take awhile to compress. Or, your blown-in component wasn't very dense.
    The blown has settled down but the r30 batts are fluffy and thick. My power bill dropped after I added the blown and the A.c. doesn't run as much.

  12. #12
    DIY Senior Member dlarrivee's Avatar
    Join Date
    Jun 2009
    Location
    Canada
    Posts
    1,172

    Default

    So you didn't measure it.

  13. #13
    Homeowner
    Join Date
    Jan 2010
    Location
    Alabama
    Posts
    1,174
    Blog Entries
    1

    Default

    Quote Originally Posted by dlarrivee View Post
    So you didn't measure it.
    Unless the power company lowered their rates over the past 3 years theres no need to measure anything but the stack of money I'm saving after I added the blown in over the batts. My power bill dropped an average of 30 bucks a month with the same hvac unit and thermostat setting at a constant 70 degrees. Hows that?

  14. #14
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    You're missing the point...obviously, adding insulation helps. But, putting blown in over a batt type compresses the batt. Your total insulation level wouldn't be as high as if you'd either used all blown-in, or put the batts on top of the blown in. IOW, you didn't get the full benefit of what you installed.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  15. #15
    Homeowner
    Join Date
    Jan 2010
    Location
    Alabama
    Posts
    1,174
    Blog Entries
    1

    Default

    Quote Originally Posted by jadnashua View Post
    You're missing the point...obviously, adding insulation helps. But, putting blown in over a batt type compresses the batt. Your total insulation level wouldn't be as high as if you'd either used all blown-in, or put the batts on top of the blown in. IOW, you didn't get the full benefit of what you installed.
    I had batts only for 7 years. 3 years ago I added 6" of blown in on top of the batts and that cost 600.00 to add it. Since I aded the blown in over the batts my power bill has been an average of 30 bucks cheaper over the past 3 years. 6" of blown did not compress the batts enough to measure or matter,the benefits out weigh the negative and my power bill proves it. It took less than 2 years for the blown in to pay for itself and last year it saved me about 350.00. So now maybe you understand why I'd rather go by what I know rather than what I'm told or read.

Similar Threads

  1. Want to add more attic insulation
    By burleymike in forum Remodel Forum & Blog
    Replies: 4
    Last Post: 10-26-2010, 08:30 AM
  2. Knob and Tube in attic / insulation
    By The old college try in forum Electrical Forum discussion & Blog
    Replies: 26
    Last Post: 02-18-2008, 07:33 AM
  3. insulation for attic stair unit?
    By alleycat in forum HVAC Heating & Cooling
    Replies: 2
    Last Post: 01-27-2008, 02:58 PM
  4. Attic Insulation - vapor barrier
    By The old college try in forum Remodel Forum & Blog
    Replies: 3
    Last Post: 01-26-2008, 01:17 PM
  5. Attic Insulation
    By Gouranga in forum Remodel Forum & Blog
    Replies: 1
    Last Post: 05-11-2006, 04:59 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •