Is an overhang of 100 mm enough for iron beam

Discussion in 'Builders' Talk' started by Sumith, Sep 12, 2019.

  1. Sumith

    Sumith New Member

    We recently had an outer wall knocked through to make access into the outhouse. Both leafs of wall, inner & outer has 7" iron beam put in. I have uploaded plenty of pics to explain.

    Looking at the work, I have some concerns that it has not been done as per the general guide lines. Questions:

    1) The opening is 1300 mm (4' 3") but the iron beam used is only resting on 100 mm on one side and 130 mm on the other side. Is this enough?

    2) The beam is not rested on full brick, but a cut one. But that brick, however is a new one put in not one that was already on the wall (I think)

    3) Is iron beam good for this job? or should it be a concrete+iron lintel?

    4) The acro props were removed same day. But slates were wedged in. Is this ok? (I am not sure if slates were used both top and bottom. I will clarify this and come back)


    Attached Files:

  2. Heat

    Heat Screwfix Select

    Have you asked building control?
    Steel beams are very strong and certainly good enough if sized correctly for load bearing.
    But I personally would have used concrete lintels there.
    I would think resting on 100mm on a fully sound wall for that span is okay, but I would have used longer beams to give 200mm each side. It wouldn’t have made it more difficult.
    Some of the Pro builders on here will give more advice
    Sumith likes this.
  3. kiaora

    kiaora Screwfix Select

    I’d be happier if the beam was laid on pad stones !

    It’s not a big deal to prop up the beam and do it properly.

    Good luck
    Sumith likes this.
  4. Hans_25

    Hans_25 Screwfix Select

    It'll most likely be just fine, but is a bit of a bodge. As above, should have used padstones and overhang should be 150mm.

    Have building control been involved or did the builder just come in and do his thing?
    nigel willson, Sumith and KIAB like this.
  5. KIAB

    KIAB Super Member

  6. Sumith

    Sumith New Member

    Building control was not involved. But the builder we used have been doing stuff for around 20 years. His earliest job I personally know dates back a few years, where a similar work was done (nothing gone wrong there, yet!).

    However when I asked him the question the response I got was this:
    When putting a beam across the width of a, say living room where one wall is shared with the next house, how will you possibly overhang more than a brick's width? And that kind of work takes place all the time (our case was different though). But it kinda got me wondering.
  7. Astramax

    Astramax Screwfix Select

    The length of time is irrelevant, notifying building control isn't!;)
  8. gas monkey

    gas monkey Well-Known Member

    It will be fine yrs ago thats how we did it and used timbers
    the steels are fine
    the 4" is ok
    slates ok
    However whats above wall/window attic pine end gable
    pad stone/ full brick on that be ok
    fret not
    but do not involve building control no need and youll be getting a rod for your own back they will charge you a small fortune and for no reason
    as for a room knock though you put in a piller so a 12 foot span you should have a 12" overhange on both ends so an8" piller tell him that
    they have been resting on a 4" wall with timber beams for years in one of my houses and not a prob but you dont do it anynore
    Sumith likes this.
  9. kiaora

    kiaora Screwfix Select

    The 100 mm is fine, it’s just the lack of pad stone, that’s the issue, for me that is.

    It’s not a big deal, the way the load on the beam is spread as the brick corses increases, like a triangle,
    There’s not an issue in real life.

    Good luck
    Sumith likes this.
  10. Richard_

    Richard_ Active Member

    That lintel needs to sit on a padstone, or engineering brick, or dense block.

    It also looks like that is a cavity wall with a separate channel for each leaf. It really should have something tying the two beams so they work together as one because you are bound to have differential movement which will result in cracks in the finished plaster. Same again for the masonry needing to be well tied.

    Ask the builder when building control are going to inspect it.

    To reassure you, none of the comments here are talking about failure or stability, it's more likely to show in annoying cracks in the plaster.
    Sumith likes this.

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