Furring out rafters

Discussion in 'Remodel Forum & Blog' started by nelsonba, Nov 9, 2007.

  1. nelsonba

    nelsonba Member

    Messages:
    118
    Location:
    Minnesota
    I'm planning to fur out 2x4 rafters with 2x2s to make room for more insulation. Can I nail them or do I need to use screws? I'll be covering them with drywall. Do I need to use longer drywall screws?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    I'd slap some construction adhesive on and screw them together. Nailing a 2x4 could be bouncy, screwing would be more direct. You'd be less likely to split things if you drilled through the 2x2 first.
  3. statjunk

    statjunk DIY Senior Member

    Messages:
    542
    Since it's furring I'd use a finish nailer. You're going to run screws through it while doing the drywall so I wouldn't bother doing to much work to keep the furring in place. You need to have a screw into the joist 1/2". Do the math to figure out what length screw you'll need for your drywall. I'd bet a 1 5/8" would do you fine.

    Tom
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    1/2 drywall + 1.5" 2x2 (maybe more), need at least a 2.5" screw. If the 2x2 isn't tight, the screw for the drywall may not catch right away and then it will jack the two apart. WIth a bead of construction adhesive there, it won't move. If you've got a nailer, then I'd forgo the screws, but still slap some glue up there.
  5. Livin4Real

    Livin4Real New Member

    Messages:
    192
    Location:
    Indianapolis, IN
    I don't know anyone that uses 2.5" drywall screws, most are 1.25" so the furring strips must be securely attached to the rafter because the drywall screws aren't going to penetrate the actual rafter, just the furring strip unless of course you want to drop twice as much money on the extra long screws to do all the drywall with.
  6. AZ Contractor

    AZ Contractor In the Trades

    Messages:
    90
    Location:
    Phoenix, AZ
    I always over-engineer things planning for the worst.

    I would glue and screw the furring strips and nail some gussets on them in various locations.

    A little extra work can make a huge difference.
  7. statjunk

    statjunk DIY Senior Member

    Messages:
    542
    Yup missed the furring strip size. When I think furring I'm thinking thin. Yeah you'll need longer screws.

    Any reason you don't just sister up the joists?

    Tom
  8. nelsonba

    nelsonba Member

    Messages:
    118
    Location:
    Minnesota
    I might

    I guess I was thinking it would be cheaper to put 2x2s on than to sister with 2x6s. But perhaps the additional cost of screws, construction adhesive, my time, etc... isn't worth it. If I sister, I assume I can just nail it together, right?

    However, If I sister them, I'm going to have nails from the roofing material getting in the way. Best to just pound them over? Or should I try to cut them off?
    Last edited: Nov 12, 2007
  9. statjunk

    statjunk DIY Senior Member

    Messages:
    542
    If you sister you're going to want to choose a smaller board like a 2x4. Given that you are attempting to add additional insulation I'd just go ahead with your furring out idea. It will be easier to acheive a better insulation result.

    Sorry for sending you in another direction that perhaps isn't the best.

    I'd glue and finish nail in your 2x2 furring. Then get some long screws to run your drywall with.

    Tom
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,324
    Location:
    New England
    If the existing rafters aren't all nice and straight, you could straighten up the ceiling with some sisters. It would be possible with furring strips, but harder as each one may be different. Even if you used a 2x6, you want it to extend below the existing lumber, so it wouldn't have to go all the way to the roof decking. A 2x6 is in the order of 5.25-5.5" wide. The roofing nails probably don't stick too far through.
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