correctly installing lintel?

Discussion in 'Builders' Talk' started by legepe, Nov 9, 2018.

  1. legepe

    legepe Member

    Hi all
    I want to place a 210 x 100 x 1800 concrete lintel above fire place, only 100mm will actually sit inside the wall the the rest will be on the outside creating a mantel piece
    My query is should this lintel only be installed with the high side (210mm) sitting vertically? or am I wrong thinking this?
    Can anyone advise
    Thanks
    legepe
     
  2. sospan

    sospan Well-Known Member

    With most chimneys the bulk of the weight is supported by the cheeks of the fireplace and it is then "corbeled" as the height rises. The front of the fireplace, is normally a single skin for the first 8 feet and then is tied in and gets thicker as it rises.

    Normally a 100mm wide lintel is good enough to support the face of the chimney breast but it depends on the construction and the strength of the sides. The strongest dimension would be with 210 vertical.

    Of the ones I have done recently, I have done two methods - one with a face screwed onto the lintel and then with a top fixed at 90 degrees and corbels to hide the screws. The other style was just a rustic beam which had keyhole brackets on the back which just slotted over screws in the lintel
     
  3. legepe

    legepe Member

    Thanks sospan
    I would really like to post some pictures but this site will not allow it..! it just keeps telling me theyre too large?
    I completed about 6 months ago a different fireplace in an old terraced house using the method that I want to do again with this one. that one hasnt fallen down but I was unaware then that the lintel was supposed to go in sitting upright.
    I didn't have to touch any of the corbles in the terraced house because the original builders opening was big enough, however with this one the property was build tin 1968 and the corbles are much lower down so for me to make sufficient opening i will have to break/remove the corbles and like youve already pointed out they are load bearing.
    How do I get around this?
    legepe
     
  4. dobbie

    dobbie Well-Known Member

    The lintel is not supposed to go in upright and is not designed for that.That is bad advice you have been given.

    The lintel would have been designed to lie flat and have the stress calculated to be installed that way.
     
  5. sospan

    sospan Well-Known Member

    Most of the fireplaces, I work on are made out of stone, so you can never tell how strong the wall is. I tend to brace the alcoves and then put in a acrow props with a strongboy head quite often this is just belt and braces.

    If you each end of the lintel, removing stonework towards the centre, you will see how it is supported, quite often the bricks or stones will be at 90 degrees to the ones removed and will support the ones above.
     
  6. sospan

    sospan Well-Known Member

    There are no calcs, it is an off the peg lintel.
     
  7. dobbie

    dobbie Well-Known Member

    Which the lintel in question is designed to be installed flat,not upright.
     
  8. Richard_

    Richard_ Active Member

    Incorrect.

    Many standard concrete lintels have a single prestressed bar in the centre. The bar is in the centre to enable the lintel to work upright or on its side. Upright would be stronger but horizontal would be strong enough for this application.

    Other lintels have bars in the bottom, they can only be used in the orientation with the bars at the bottom.
     
    Last edited: Nov 10, 2018
  9. stuart44

    stuart44 Active Member

    Composite concrete lintels have the bar in the centre, as the 3 courses of brickwork above form part of the lintel. The rough concrete should really go at the top to form a key for the brickwork.
    Non composite lintels that can directly take a point loading will have steel at the bottom and maybe the top as well.
     
    Richard_ likes this.
  10. Richard_

    Richard_ Active Member

    Not forgetting to prop lintels over 1200 long until the mortar had cured.
     
  11. legepe

    legepe Member

    Thanks for all you views on the mantel element or lintel...
    However, after looking at whats needed on this to open up the fire place.. it is getting much more complicated than simply putting a lintel in the face of the fireplace..!
    My problem is that the property was built in 1968 and the original opening is only around 500 wide 600 high and the cobelled brickwork supporting the stack starts around one brick up from the top of the opening.. so any ideas how IF POSSIBLE i can make it bigger as I guess I cannot take out any of the cobelled brickwork?
    Hope Im making my problem with this clear to understand
    Any advice on this very welcome.
    legepe
    ps wish this site would allow some pics!
     
  12. sospan

    sospan Well-Known Member

    It does allow pics, you just have to make sure they are the correct size
     
  13. legepe

    legepe Member

    is 2.42mb JPEG too large.. ive tried to convert it to all other formats and theyre all larger?
     
  14. chippie244

    chippie244 Well-Known Member

    I think 2 Meg is the limit.
     
  15. legepe

    legepe Member

    Ok thanks chippie... here are a couple of pics.. any advice how this opening can be made wider and higher I would appreciate very much... if it isnt possible then any suggestions would be welcome.. thanks
     

    Attached Files:

    • 1.jpg
      1.jpg
      File size:
      1 MB
      Views:
      22
    • 2.jpg
      2.jpg
      File size:
      672.6 KB
      Views:
      22
  16. sospan

    sospan Well-Known Member

    At what height are you installing the lintel ?
     
  17. legepe

    legepe Member

    Here is one I completed around 6 months ago.. however it was an old terraced house and the corbelled brickwork inside the opening was much higher therefore it never had to be touched.
    I would ideally like to have something similar
     

    Attached Files:

  18. sospan

    sospan Well-Known Member

    The good thing is that the chimney breast and flue looks well built.

    The problem as you have realised is that the corbelling is supporting the infill and structure in the centre of the chimney.

    I can't think of an easy an economical way of making the opening taller. I had to get a range cooker into an opening and was faced with a similar challenge. The structure wasn't the best anyway, so it ended up as a demolition and rebuild. Which in your case would be a bit extreme.

    sorry run out of options
     
  19. legepe

    legepe Member

    Ive just thought of a possible solution..! see pic...
    1 - 210x100x1800 lintel how I originally wanted flat side down (need to be absolutely sure it will be the right way to take stress of weight above)
    2 - make opening in front face of bricks above lintel and locate stack
    3 - take out layer of bricks in the sides of stack and break into partition wall
    4 - put two 100mm lintels from partition wall to rest on front lintel (partition wall is breeze blockwork - the brickwork on stack is built free standing/not tied into partition wall)
    5 - remove brickwork up to lintel on fireplace face, remove corbelled brickwork, and remove inside cheeks of fire place
    6 - brick up cheeks to bottom of lintel
    what do you think? will it work?
     

    Attached Files:

    • 1.jpg
      1.jpg
      File size:
      1 MB
      Views:
      10
    Last edited: Nov 14, 2018
  20. sospan

    sospan Well-Known Member

    This is the point it becomes dangerous and expensive. If you are lucky the chimney will look like an upside down funnel

    upload_2018-11-14_17-36-29.png

    With a lintel your proposing something like this

    upload_2018-11-14_17-42-50.png

    It would be better to have the lintels in parallel one at the front and the other on the partition wall. However, if you want a wood burner or similar you will have to leave a gap between them large enough for a flue and high up enough that it isn't affected by the radiant heat
     

    Attached Files:

Share This Page