150mm wide steel landing on 100mm wide block work

Discussion in 'Builders' Talk' started by William Padbury, Jun 23, 2019.

?

Supporting a 150mm steel in the same plain as a 100mm wide block work wall

  1. Return block work at reveals

    1 vote(s)
    50.0%
  2. Get SE to change steel spec

    1 vote(s)
    50.0%
Multiple votes are allowed.
  1. William Padbury

    William Padbury New Member

    Hi all. I'm currently renovating a bungalow. Which involves a 4300mm X 150mm x150mm steel spanning a new bifold opening.
    My question is how do you fully support a 150mm wide beam on a 100mm block work cavity wall?
    SE has shown a 100mm wide X 150mm deep X 330mm long padstone on his workings but this still makes no sense to me.
    Why have s 150mm wide steel only supported by 100mm padstone / block work. Surely there's a risk of the steel rolling if it's unsupported under the 50mm sticking into the cavity?
    I expect most responses will be consult SE which I plan to do. He's not the most accomodating guy so I just wanted to get the thoughts of others before going back to him.
    Any ideas or advice appreciated
     
  2. gas monkey

    gas monkey Well-Known Member

    is there a drawing of the steel
     
    andyscotland likes this.
  3. Diyloser

    Diyloser Active Member

    Why would there be 50mm into the cavity.??
    It should be set centrally over the wall.

    I suppose you could ask if a taller narrower steel could be specified.
     
  4. gas monkey

    gas monkey Well-Known Member

    how meny pads are id
    4
     
  5. sospan

    sospan Screwfix Select

    They can make amazingly huge mistakes. We had the same problem but the SE had specified TWO like yours for a 100mm wall. The annoying thing for us is that we request we built a 1m square engineering brick pillar to support them. Pillar built and left to harden, ordered the steels, carried them in and then realised the error - expletive, expletive, expletive. Even when we had to cut down the pillar we were still swearing. Boy did that cost the SE some money.

    So yes they do make mistakes
     
  6. William Padbury

    William Padbury New Member

    Diyloser

    Thanks for getting back to me. How Do you put it centrally over the wall without bridging the cavity. I plan to put it flush with the outer side of the outer leaf as there is a timber frame gable end being built above in the loft conversion as suggested by SE. Hence leaving 50mm in the cavity
     
  7. Severntrent

    Severntrent Screwfix Select

    Looking at it logically the pivot point were it to roll would be at the inner face of the block work. 50mm is overhanging this point into the cavity but 100mm is "overhanging" the other way onto the blockwork so the net effect is for it to remain in place by a ratio of 2 to 1. This together with the fact that the web of the steel which carries the load down to the wall is contained on the overhang on the blockwork considerably increases this ratio. In theory if the load acting on the top flange of the steel was mainly acting in the area above the 50mm overhang then the overturning force could be greater than the restoring force but I assume this will not be the case.
     
  8. William Padbury

    William Padbury New Member

    Thanks Severntrent.... That's a valid point. But as a carpenter myself it just doesn't 'feel' right to have that 50mm not bearing. I don't see the point of having a 150 mm steel but only use 100mm of it to transfer the load down through the block work.
    But maybe that's why I'm a carpenter and not an SE!
     
  9. Severntrent

    Severntrent Screwfix Select

    The steel specified is actually a 150 x 150 universal column and I assume this is needed to achieve a depth of 150mm whilst maintaining the required strength. An equivalent universal beam 100 wide would require a depth of 203 or 254 depending on what the actual loading is.
     
  10. William Padbury

    William Padbury New Member

    Spoke to SE and basically has told me exactly what you said about the middle of the steel still being over the block work. He's given me the option to have a 10mm plate welded to the bottom to pick up the other side of the wall. Avoids any rolling and gives me something to build off up to ceiling height. Probably go with this.
    Guess the thermal bridging from such a plate would be minimal?
     
  11. Diyloser

    Diyloser Active Member


    If there's room, it shouldn't be a problem having a taller steel should it. ?


    You dont what any thermal bridge if you can help it.
     
  12. Severntrent

    Severntrent Screwfix Select

    No
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice