1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

How to fix support beam

Discussion in 'Roofing and Guttering' started by NicKarla, 8 Feb 2021.

  1. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom
    Following on from the advice from my other thread I’m am needing to add some supports similar to a few that’s there already (see red line in picture).

    I have some c24 4x2 which will be used and was intending to screw them in until I read that screws are less favourable and nails should be used due to their flexibility.

    The idea of hammering into my beam is concerning and with the fear of doing more harm than good I would prefer to screw. Is this really a bad idea? Is a nail gun (which I don’t have) the only way forward?
     

    Attached Files:

  2. Sponsored Links
  3. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    33,920
    Thanks Received:
    4,606
    Location:
    West Mids
    Country:
    United Kingdom
    How will/can a rod of metal, whether a screw or nail, fixed through two pieces of timber held tight together, "flex"? There is just no way.

    Use screws, avoid banging around in a loft.
     
  4. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom

    Attached Files:

  5. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    33,920
    Thanks Received:
    4,606
    Location:
    West Mids
    Country:
    United Kingdom
    Yes those turbos are quite good for fitting without a pilot hole. You'll probably need an impact driver though. Or normal 4 or 5mm screws if predrilling.
     
    • Thanks Thanks x 1
  6. Notch7

    Notch7

    Joined:
    15 Sep 2017
    Messages:
    25,156
    Thanks Received:
    1,782
    Location:
    S. Uplands
    Country:
    United Kingdom
    screws are unsuitable for load bearing applications in shear -for example joist hangers

    screws are fine for your application..... or the coach screws youve linked.

    A carpenter wouldnt think twice about using screws for doing this, 80x5 probably (or whatever he had in the van!)
     
    • Thanks Thanks x 1
  7. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom
    When you say predrilling do you mean using a pilot hole? I don’t have an impact drill so would a small pilot hole be appropriate, eg 2-3mm?

    screwfix have these 5x80 with torx head to make screwing easier. Only down side is the countersunk head. What do you think about these or is it best to stick to the 6x90 coach screws?


    https://www.screwfix.com/p/spax-wirox-tx-self-countersunk-woodscrews-5-x-80mm-100-pack/2969p
     
  8. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    33,920
    Thanks Received:
    4,606
    Location:
    West Mids
    Country:
    United Kingdom
    You'll need to drill the one timber wider than the screw to allow the screw to pass through it and pull it in tight.

    For the other timber, the screw may go in without drilling - some self cutters (Turbo Gold or suchlike) or twin thread may do - put some soap or candle wax on the thread and it should fly in.

    Otherwise you will have to pilot the hole with a bit about 1/2 to 3/4 as wide as the screw
     
    • Thanks Thanks x 1
  9. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom
    Perfect, thank you.

    Lastly, would I be right in thinking that ‘A’ would be better screw placements than ‘B’?
     

    Attached Files:

  10. Sponsored Links
  11. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    33,920
    Thanks Received:
    4,606
    Location:
    West Mids
    Country:
    United Kingdom
    "A" would be better.

    I'm not sure of the purpose of these, as that looks like a trussed roof, so these braces should not be necessary. If these are a necessary structural function then they should be fitted with a single coach bolt, square washers and a spur washer (timber connector) between the timbers. But if these are not really necessary (ie not specified by a qualified person) then screws will be fine.
     
  12. How is a screw unsuitable for applications in shear???
     
  13. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom
    The purpose is to add structural support. It isn’t critical but the end of the roof has been put up badly. It looks like they just added a few ends on. I’ve been advised that it would ‘help’ in the event of heavy snow and for long term durability.

    Im more than happy to drill a hole and put a bolt through but I thought that drilling holes 10-12mm for a coach bolt was a bad idea as it can effect the structural integrity of the trusses.
     
  14. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    33,920
    Thanks Received:
    4,606
    Location:
    West Mids
    Country:
    United Kingdom
    I can't see how a collar is going to help a truss, and certainly not one that far up. But 10 or 12mm hole is not going to may any difference.
     
    • Thanks Thanks x 1
  15. NicKarla

    NicKarla

    Joined:
    23 Aug 2015
    Messages:
    80
    Thanks Received:
    2
    Country:
    United Kingdom
    Last edited: 9 Feb 2021
  16. Notch7

    Notch7

    Joined:
    15 Sep 2017
    Messages:
    25,156
    Thanks Received:
    1,782
    Location:
    S. Uplands
    Country:
    United Kingdom
    screws are hardened and vulnerable to breaking under high shear stress

    wire nails bend a bit
     
  17. Agreed you might get a bit more bend from a nail compared to a similar sized screw, but completely wrong to say that screws are 'unsuitable' for shear loading...
     
Loading...

Share This Page