Klingspor's Woodworking Shop (Festool) Ad #2

Special Events in the next 30 days

Page 1 of 2 1 2 LastLast
Results 1 to 15 of 20
  1. #1
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    196
    Visit Freq
    5.65 visits/week
    Threads
    55
    Classifieds
    0

    Insulation INSTALL Question ??

    So I found some rolls of R-30 that are 15" wide and 25' long. Problem is my ceiling joists are 34" apart, so if I run two rolls side by side between the joists, I'll have a 4" gap if I snug them together and against one of the joists, or if I spread them out between the joists, it would be a little over 1" gap between the rolls on average. Neither of these are going to be very efficient.

    I can cut the 25' rolls into a bunch of 34" lengths to install nice and tight between the joists. I know this is probably the best option but it will be very laborious climbing up and down a ladder and cutting the short pieces.

    Question is: Can I install the roll across [perpendicular to] the joists so that it simply rolls up and over the 2x6. This would create a gap between the insulation and ceiling along each joist, but there wouldn't be any gaps between the rolls. I guess essentially I would be heating a small crevasse between the ceiling and insulation along each joist. There would still be a tight fit across the attic and between the rolls. this will make for a much quicker install, but will it be as efficient? In addition to the R-30 I'm installing I have the rolled insulation immediately under the metal roof that is about R-9.

    I searched the WWW and can't find any thoughts, so I figured I'd ask the 'experts' here.

    Attached Images Attached Images

  2. #2
    User
    DQ

    Nickname
    Jim
    Join Date
    May 2008
    Location
    Lexington, SC
    Posts
    1,172
    Visit Freq
    1.08 visits/week
    Threads
    18
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    I like going the long way but adding some 24 inch wide rolls and then putting a 24 and a 15 into each cavity. That will have to be compressed a little but should work. I wouldn't leave any gaps. That kind of defeats the purpose of putting in the insulation.

  3. #3
    Senior User
    Nickname
    Jeff
    Join Date
    Mar 2008
    Location
    Rougemont, NC
    Posts
    5,987
    Visit Freq
    6.88 visits/week
    Threads
    564
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    No help here, but how in the world did you get or specify ceiling joists 34" inside-to-inside (35.5" on center)?

  4. #4
    Corporate Member
    DQ
    Phil S's Avatar
    Nickname
    Phil Soper (67)
    Join Date
    Mar 2008
    Location
    Raleigh, NC
    Posts
    4,025
    Visit Freq
    9.00 visits/week
    Threads
    492
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Across the joist would be best - just roll them out and fill any voids

  5. #5
    Senior User
    Nickname
    Jeff
    Join Date
    Mar 2008
    Location
    Rougemont, NC
    Posts
    5,987
    Visit Freq
    6.88 visits/week
    Threads
    564
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Quote Originally Posted by Phil S View Post
    Across the joist would be best - just roll them out and fill any voids
    So David should cut them 34" long x 15" w?

  6. #6
    Senior User
    DQ
    Skymaster's Avatar
    Nickname
    Jack (77)
    Join Date
    Aug 2009
    Location
    Zebulon, NC
    Posts
    1,630
    Visit Freq
    6.31 visits/week
    Threads
    40
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Add joists where you need em, in long run much easier than trying to go cross ways, trying to jury rig etc.

    I agree with Jeff, that does not meet any code and is not good.IMHO twas me, i would layout all your joists,ie measure them all, then layout on 24" if you want 24 or 16" Yes a bunch of work but well well worth it,this way IT MEETS CODE IF YOU WANT TO SELL IT, the present way could get knocked down from a home inspection.

  7. #7
    Corporate Member
    DQ
    Gotcha6's Avatar
    Nickname
    Dennis
    Join Date
    Jan 2007
    Location
    Ivan's Corner (Monroe), NC
    Posts
    5,485
    Visit Freq
    6.81 visits/week
    Threads
    343
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    How old is the house? Does it have an old wooden,possibly beaded board ceiling above drywall or Celotex? That would explain the wide spacing.
    WHAT BOX?

  8. #8
    Corporate Member
    DQ
    Bill Clemmons's Avatar
    Nickname
    Bill (69)
    Join Date
    Mar 2010
    Location
    Liberty, NC
    Posts
    5,848
    Visit Freq
    6.96 visits/week
    Threads
    247
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    It may be a little late for this, but have you considered having insulation blown in? That's what I did for my shop.
    I'll gladly tell you how I do something. Just please don't confuse that with the right way to do it, and almost certainly not the only way.


  9. The following user says Thank You to Bill Clemmons for this useful post:


  10. #9
    Corporate Member
    DQ
    Phil S's Avatar
    Nickname
    Phil Soper (67)
    Join Date
    Mar 2008
    Location
    Raleigh, NC
    Posts
    4,025
    Visit Freq
    9.00 visits/week
    Threads
    492
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    I am quite sure David is insulating his shop which is a pole barn, which commonly have wide rafter and joist spacing. It is code compliant as long as the members are sized correctly. Does anybody remember Deck Houses from years back, they had joist and rafter spacing of 48"

    I am suggesting that he run the insulation above the joist and perpendicular to them. That would make a great thermal blanket

  11. The following 2 users say Thank You to Phil S :


  12. #10
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    196
    Visit Freq
    5.65 visits/week
    Threads
    55
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Quote Originally Posted by Phil S View Post
    I am quite sure David is insulating his shop which is a pole barn, which commonly have wide rafter and joist spacing. It is code compliant as long as the members are sized correctly. Does anybody remember Deck Houses from years back, they had joist and rafter spacing of 48"

    I am suggesting that he run the insulation above the joist and perpendicular to them. That would make a great thermal blanket
    Yes, exactly. Engineered, stamped drawings AND inspected by local county inspectors.

    Was just looking for advice on running the insulation over the joists. I do appreciate all the concerns about proper building techniques. Just looking for different advice.

  13. The following user says Thank You to DSWalker for this useful post:


  14. #11
    Corporate Member
    DQ
    Jim M.'s Avatar
    Nickname
    Woody
    Join Date
    Mar 2007
    Location
    New Church, VA
    Posts
    1,502
    Visit Freq
    6.96 visits/week
    Threads
    76
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    David since its your pole barn you should be fine if it has constant heating and cooling. My only concern would be moisture building up in the dead air space if the temperture in the shop fluctuates too much.
    Last edited by Jim M.; 12-05-2017 at 08:10 AM.
    Measure twice... cut once... SCREAM LOUDLY... get another board

  15. The following user says Thank You to Jim M. for this useful post:


  16. #12
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    196
    Visit Freq
    5.65 visits/week
    Threads
    55
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Quote Originally Posted by Bill Clemmons View Post
    It may be a little late for this, but have you considered having insulation blown in? That's what I did for my shop.
    Definately considered that, but was looking for more cost savings via Vraigs list and OfferUP. Ended up getting 15 rolls of r30 for $150. So I'm working with what I have.

  17. The following user says Thank You to DSWalker for this useful post:


  18. #13
    Senior User Fishbucket's Avatar
    Nickname
    Joe (51)
    Join Date
    Sep 2016
    Location
    Franklinville, NC
    Posts
    212
    Visit Freq
    5.31 visits/week
    Threads
    8
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    If its kraft backed Insul, I'd cut and fit tight in between ceiling joists as normal instalation
    If its not, I'd lay out in full rolls across the joists.

  19. The following user says Thank You to Fishbucket for this useful post:


  20. #14
    Staff Advisor
    Corporate Member
    DQ
    Joe Scharle's Avatar
    Nickname
    Joe (74)
    Join Date
    Sep 2005
    Location
    New Bern, NC
    Posts
    5,448
    Visit Freq
    6.08 visits/week
    Threads
    683
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Quote Originally Posted by Fishbucket View Post
    If its kraft backed Insul, I'd cut and fit tight in between ceiling joists.
    If its not, I'd lay out in full rolls across the joists.

    Me too
    Always be yourself because the people that matter don't mind, and the ones who mind, don't matter.

  21. The following user says Thank You to Joe Scharle for this useful post:


  22. #15
    Corporate Member
    DQ
    Gofor's Avatar
    Nickname
    Mark
    Join Date
    Mar 2006
    Location
    Goldsboro, NC
    Posts
    3,036
    Visit Freq
    6.50 visits/week
    Threads
    76
    Classifieds
    0

    Re: Insulation INSTALL Question ??

    Rolling it out across the joists will give a better thermal barrier because it also insulates the joists which are a thermal transfer across your insulation. Its not the gap between the ceiling and the insulation you need to worry about because it will be a dead air space. The whole purpose of insulation is to create a dead air space (normally within the insulation itself). The dead air isn't the big transfer of heat, its the solids. Insulation is puffed up to create more dead air and less mass (solids). If concerned about moisture on top, lay plastic sheeting over the insulation as you work your way down the ceiling which will also increase the effectiveness of the insulation if it doesn't have kraft paper on it.

    Go
    Practicing at practical woodworking

  23. The following 2 users say Thank You to Gofor :


Similar Threads

  1. Insulation
    By DSWalker in forum Workshop Discussion
    Replies: 6
    Last Post: 11-29-2017, 09:36 PM
  2. Insulation Question
    By DSWalker in forum Workshop Discussion
    Replies: 2
    Last Post: 08-14-2017, 11:01 AM
  3. Insulation Question
    By Mike Wilkins in forum Workshop Discussion
    Replies: 11
    Last Post: 11-20-2011, 06:29 AM
  4. Insulation question
    By jrs in forum Workshop Discussion
    Replies: 9
    Last Post: 06-19-2009, 11:35 AM
  5. Where to buy insulation?
    By HardRock in forum Where Can I Find, Buy or Sell
    Replies: 7
    Last Post: 01-31-2006, 01:37 PM

Posting Permissions

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