Do these new joist notches look alright to you?

Discussion in 'Carpenters' Talk' started by Jose17, Jul 13, 2018.

  1. Jose17

    Jose17 New Member

    The builder has replaced all the bathroom joists as the old ones were in terrible condition.

    He has bolted a piece of timber on the wall with M12 rods and used a steel plate on the outside wall to hold it together.

    All timber is C24.
    Timber size: 47x170
    Span: 3.15m
    300 Centres with noggings.

    I am worried about the way the timber has been notched out to fit into the RSJ.

    The timber is 170 deep but notched out is only leaving between 120-130 in the RSJ.

    The bath will be positioned above the joists nearest to the RSJ.

    Am I being paranoid? Thanks.

    View from below.

    Joists shown notched into steel


    Timber bolted to the wall with hangers for joists.
  2. Jord86

    Jord86 Screwfix Select

    He's cocked up, rather than sit the joists on a 3x2 in the web of the rsj he should have bolted a timber into the web on edge and used joist hangers, or just ran the joists straight into the steel web with a tiny notch out the bottom to get the ceiling flush. The joists are 2" higher than they should be, hence the large notch he's taken from the top.
    KIAB and Deleted member 11267 like this.
  3. blarblarblarblar

    blarblarblarblar Active Member

    Is it the best way to do it, probably not. Is it a problem, probably not.

    If you don’t do it my way, that doesn’t make it wrong.
    Alwaysworking likes this.
  4. Jord86

    Jord86 Screwfix Select

    It is a problem, the builders reduced 7x2's to 5x2's, for a 3m plus span.
    KIAB likes this.
  5. KIAB

    KIAB Super Member

    Right cock up.
  6. Jose17

    Jose17 New Member

    Thanks for your reply. A cock up is one thing, and a problem is another. With the ceiling height we wanted he couldn't put them flush into the web of the steel.

    I'll get the building officer over to sign it off, should I be worried? thanks for your reply.
  7. AlvyChippy

    AlvyChippy Active Member

    6x2 are up to 3.4m span are ok, having 5" (+2") on the top- you'll be alright
    Alwaysworking likes this.
  8. Isitreally

    Isitreally Super Member

    It would have been better do like this.


    But as Alvy said above, it should be alright, the BCo will let you know for sure.
    Alwaysworking and KIAB like this.
  9. Jose17

    Jose17 New Member

    That was the original idea I suggested but because of the ceiling already being low, we wanted to gain maximum height so the notching was the only way we both came up with but looking at it in hindsight it isn't the best way.
  10. Jord86

    Jord86 Screwfix Select

    Without seeing it in person it's awkward to surmise, but why couldn't another course of bricks be removed in the first place then lift the rsj up the 75mm, it would lower your headroom in the room above, but then it's one or the other.
    KIAB and Deleted member 11267 like this.
  11. He could have used 5x3 timbers which would be acceptable for the span.
  12. Jose17

    Jose17 New Member

    We bought the house with the steel/extension already done.

    I've spoken to a friend who has suggested welding steel pieces under the RSJ to support another 2x4 base plate next to the one in the web of the RSJ to add more support.
  13. Alwaysworking

    Alwaysworking Active Member

    Wow that was a quick turnaround. Think the #3 comment summed it up but was shot down.
  14. Jord86

    Jord86 Screwfix Select

    How do you mean?
  15. stevie22

    stevie22 Screwfix Select

    OP: do you need to worry? No is the short answer.
    blarblarblarblar and chippie244 like this.
  16. Allsorts

    Allsorts Super Member

    If 5x2s or 6x2s are ok for that span, then what you currently have, Jose17, is still much better. The fitted 7x2 joists have not been reduced to effective 6x2s or 5x2s, but are still 7x2s for most of its length so will be far stronger and more sturdy than smaller joists.

    Had the guy chopped an inch or two out of the joist's thickness further away from the wall, then that would certainly have been a problem. But, as it is, the forces on the joists at the notched ends are almost totally downwards sheering forces, and a dancing elephant wouldn't make them sheer off against the steel's web.
    chippie244 likes this.
  17. Jose17

    Jose17 New Member

    Thank you all for your input. Attached are a couple drawings I have done which I think may solve the issue.

    I will pack out the web of the steel with timer and screw it in to the side of each joist. I will then hang joist hangers off the packer timber around the joist. This should then take the load of the joist from before where it is notched.

    The second option is to weld a bottom plate on the steel and pack that with 4x2 for the joist to sit on.

    Hanger1.jpg Hanger2.jpg FullStructuralFrameWWW.png
  18. stevie22

    stevie22 Screwfix Select

    What you have is fine. You don't need to do anything.

    Are the works being done under Building Control? Is BCO happy?
    Allsorts likes this.
  19. Jose17

    Jose17 New Member

    I haven't told the local authority yet but I will call them to visit... Would BCO visit the once when I say it is finished or so they generally come before hand?

    I am replacing ground floor joists too so I wanted to do it in one visit to prevent additional visit costs.
  20. Allsorts

    Allsorts Super Member

    I really do not see an issue with what you currently have. IF 5" or 6" x 2s are an ok size for that joist span, then what you have is miles better. Do you see that they haven't really turned these joists in to smaller ones as the notches are at the very ends and on the top. It is not uncommon for roof/ceiling joists to bevelled like that on their upper corners to cope with roof slopes; provided the bottom of the joist is not notched, and provided the upper notch/bevel is short, then the beams are not weakened to any significant degree.

    As Stevie says, run it past the BCO - the expert - and go with what he/she says.

    Adding the extra steel plate and stuff like that is effectively meaningless unless you have it spec'd up by an SE (after they've stopped laughing). Otherwise, it's as much a 'bodge' as the original job; it might look good, it might add strength, but who on this planet can tell you in truth what difference it'll make unless it's been calculated, spec'd and then welded by a coded tradesperson?

    Sheeeesh. :)

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