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Drilling joists

  • 25-02-2020 10:13pm
    #1
    Davy87
    Registered Users, Registered Users 2 Posts: 17 ✭


    Can joists still be drilled for wires. Heard there new building regs against this


Comments

  • #2
    kieran.
    Registered Users, Registered Users 2 Posts: 1,175 ✭✭✭kieran.


    Davy87 wrote: »
    Can joists still be drilled for wires. Heard there new building regs against this


    Tgd part A

    1.1.2.5 Notches and holes in simply
    supported floor and roof joists should be within
    the following limits:
    (a) notches should be no deeper than
    0.125 times the depth of a joist and
    should not be cut closer to the support
    than 0.07 times the span, nor further
    away than 0.25 times the span,
    (b) holes should be no greater diameter
    than 0.25 times the depth of the joist,
    should be drilled at the neutral axis,
    should be not less than three diameters
    (centre to centre) apart and should be
    located between 0.25 and 0.4 times the
    span from the support, and
    (c) the horizontal distance between any
    hole and any notch should not be less
    than the depth of the joist.

    Homebond manual manual also has a diagram/detail.


  • #3
    Davy87
    Registered Users, Registered Users 2 Posts: 17 ✭Davy87


    kieran. wrote: »
    Tgd part A

    1.1.2.5 Notches and holes in simply
    supported floor and roof joists should be within
    the following limits:
    (a) notches should be no deeper than
    0.125 times the depth of a joist and
    should not be cut closer to the support
    than 0.07 times the span, nor further
    away than 0.25 times the span,
    (b) holes should be no greater diameter
    than 0.25 times the depth of the joist,
    should be drilled at the neutral axis,
    should be not less than three diameters
    (centre to centre) apart and should be
    located between 0.25 and 0.4 times the
    span from the support, and
    (c) the horizontal distance between any
    hole and any notch should not be less
    than the depth of the joist.

    Homebond manual manual also has a diagram/detail.

    Or is it a new things that's gonna come in ?


  • #4
    adrian92
    Registered Users, Registered Users 2 Posts: 566 ✭✭✭adrian92


    Davy87 wrote: »
    Can joists still be drilled for wires. Heard there new building regs against this

    I think that if the joist is drilled about two-thirds down it doesn't affect the strength of the joist.

    Cutting a notch not a good idea as it weakens the joint

    Others may correct me if I am wrong


  • #5
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    adrian92 wrote: »
    I think that if the joist is drilled about two-thirds down it doesn't affect the strength of the joist.

    Cutting a notch not a good idea as it weakens the joint

    Others may correct me if I am wrong
    Drilling should be half way down imo. A joist is in compression above centre and tension below centre in the span areas away from supports, and the opposite at support areas. So half way down is a neutral zone.


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