Worried about gallows brackets under chimney stack

Discussion in 'Builders' Talk' started by cathlang, Apr 5, 2016.

  1. cathlang

    cathlang New Member

    Hello everyone,

    I've been googling stuff about this for days and have finally decided I need a bit of input as I'm concerned about something we've been advised is totally acceptable in our house. I'm sorry that this will be such a long post but in don't want to miss out any potentially vital info!

    We have a 3 storey Victorian terrace, totally derelict and run down when we bought it 18 months ago. The main house is 3 storeys (has always been so, not a loft conversion). There is an offshot (hope that's the right word!) at the back of the house which is 2 storeys with a pitched attic space above. This has the kitchen on the ground floor, bedroom on the first floor.

    We are working on the back bedroom in this offshot section (actually making it a bathroom). When we bought the house the chimney breast had been removed from the kitchen completely. When we have removed floorboards in the bedroom (above the kitchen) we found that the chimney breast (still present on the first floor and in attic area) is not adequately supported - it appears to be balancing on a piece of wood!

    We realised that this needs more support and decided that we may as well remove the chimney breast from the first floor also, and insert the support system in the loft. We contacted a structural engineer who apparently specialises in period houses. He came and said that gallows brackets/a lintel are in order and can't be fixed easily with bolts / resin stuff into the attic brickwork. He gave us a full report and offered to have the brackets made to the correct specification, and assured us that he has used this system many times in similar houses. The brackets arrived ( 2 large brackets with a steel shelf across, all welded into 1 piece) plus instructions for a builder and now I'm starting to panic! I mean, the structural engineer will know what will be passed by building control more than I do....I may be being paranoid. But when I read the guidelines around using gallows brackets I have concerns.

    The guidelines I've read state that the chimney stack remaining inside the house needs to be "equal to or greater than" the height of the chimney outside the house/on the roof. The chimney on the roof is 14 bricks high. The guidelines I've read also state that the brackets cannot be inserted under a purely vertical bit of chimney stack.

    In light of both of these points, I think we'd have to leave a stack (inside the house) of at least 16 bricks (at least). This means that the brackets are inserted under some of wider/diagonal section of the flue....which I understand is more supportive.

    My concerns are:

    1. The point at which we'd need to insert the brackets will be at least 4 foot across, the 2-bracket device we have is 2 foot wide. Should we not have a third bracket to widen this? Engineer advises that the lintel will accommodate for any shortfall in width.

    2. The guidelines state that gallows brackets can't be used on a breast more than 340cm deep - ours is 343cm deep. Will this be a problem with building regs? Again, I'm told it's fine.

    3. The mortar in the attic brickwork is crumbly in certain places.

    4. Our neighbour has removed on half of the chimney breast on the ground floor of the house. The back half of the chimney breast has been left, and in fact extended to make a dividing wall in the kitchen (to create a utility room). Does the fact that one side of the chimney breast has been removed affect our ability to use gallows brackets?

    Sorry for all the questions, but we've had a few (expensive) nightmares with the house and I am terrified of taking any risks whatsoever.

    Thank you to anyone who had the patience to read this!
     
  2. cathlang

    cathlang New Member

    Also (sorry) are gallows brackets acceptable in a 3 a storey house - the offshot section of the house is 2 storeys however.
     
  3. A dilemma indeed! I can see that from the point of view of a clear-headed layman (that's you...) it might seem as tho' there are issues that are potentially not covered.

    Bottom line, tho', is that the BCO will be coming out to check this job? And the SE did actually come out to visit your house, and presumably had a good look?

    And you have been back in touch with him and he has reassured you it's all ok?

    Cooooool.

    What's the worst that can happen?! :) If your house does fall down, then on the SE's head be it.

    Ok, perhaps not the best choice of words...

    Bottom line - an SE (the professional) has specified a bracket and had it made for you (you have his report and calcs etc?)

    The BCO (another supposed pro...) will be checking this to ensure it's been installed as per the recommendations? Coool again.

    You have pointed out your layman's concerns (do you have a record of this, by the way - was it done by email? If not, write down everything you asked and what the replies were.)

    I doubt anyone on here can say definitively whether it's 'ok' or not based on an even detailed written explanation. All we can look at is that two professionals in their field (along with the builder who will be installing it - another 'pro'...) have said 'Yea'.

    I suspect you are chust (quite reasonably) over-analysing it.
     
  4. cathlang

    cathlang New Member

    Thank you! I probably am paranoid. I have the written report and a thread of emails where I have raised my concerns and been reassured. He just replied saying the the guidelines I have been reading online are out of date and it will be fine. We are indeed getting it signed off by BC afterwards....

    He did come and have a look, but seemed to just say "gallows brackets" straight away as that's what he always recommends (is the impression I got). And then the bracket system arrived and seemed really small!

    We've just had nightmare upon nightmare with this house and I've prevented a few near misses by being very cautious so it's a bit of a Pavlovian response.
     
  5. Phil the Paver

    Phil the Paver Screwfix Select

    can you post a pic or 2 of the brackets.
     
  6. KIAB

    KIAB Super Member

    A right mess, wonder if your neighbour used gallow brackets to support load?, etc,etc.
    If possible, I would look to remove the whole stack, more work, but peace of mind.

    Need some photo's like Phil said.
     
  7. Ahem, a wee timber lintel has held the bludy thing up for gawd knows how long, so really...?
     
  8. KIAB

    KIAB Super Member

    OP said, it appears to be balancing on a piece of wood!:eek:

    Here, someone use a piece of 3"x2" in place of a brick to support a lintel over a doorway, it explained why bathroom had a slight fall on it, & a crack in the kitchen wall below, what was a simple job to remove kitchen wallpaper ended up rebuilding whole corner, plastering,etc.

    So don't trust wood for supports.:)
     
  9. cathlang

    cathlang New Member

    image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg image.jpeg Hi guys. Thanks for all your help. I'm not sure that neighbours semi removed chimney breast has got a bracket in, probably not.

    We've just spend a small fortune on the roof so I'm keen to leave the chimney in and sort in internally. Here are some pics. There are two pics of a hole in the first floor chimney breast well where you can just about see the bit of wood! I've also photographed the brackets - upside down - and the chimney inside and out.
     
  10. And is there meant to be a lintel sitting on top of that bracket or summat?

    Where does it go in relation to the stepped-out chimney breast in pic 2?
     
  11. KIAB

    KIAB Super Member

    Can you rotate photo's right way up.:confused:
     
  12. cathlang

    cathlang New Member

    They are the right way up (at least on my iPad they are)!!!! The bracket is being stored in the hall upside down.

    There will be a concrete lintel / shelf on top of the iron bracket thing. Bracket will be bolted into the bricks with some resin stuff (all in the instructions) and a layer of mortar packed between the lintel and the lowest brick.

    We were planning on putting the bracket about 16 bricks down from the roof. The chimney is 14 bricks high above the roof. This would mean it the lintel sits 4-5 bricks under the purely vertical part of the shaft - so, where the bricks start stepping down diagonally - about 4-5 "steps" down << at this point it measures 4 foot across. Although the engineer assures me we can out it as high as we like!
     
  13. That bracket is designed to go under the brickwork where the corbelling stops.
     
  14. KIAB

    KIAB Super Member

    Like this.


    [​IMG]
     
  15. If it was designed to go lower it would have another bracket,not being fixed with a cantilever effect.
    There would be 3 bracket's like KIAB'S photo.
     
  16. cathlang

    cathlang New Member

    Thanks Deleted member 11267 .....forgive me for being thick..... do you mean the bracket we have is not suitable to go 1/3 of the way down the corbelling brickwork ? It is only suitable to go under vertical brickwork ? I can ask for another bracket system and put them together? I'm so worried about taking chances! Thanks, Catherine
     
  17. cathlang

    cathlang New Member

    Sorry I don't think my post above makes sense! If you wouldn't mind explainiing in an idiot proof way lol o_O
     
  18. Astramax

    Astramax Super Member

    Is you chimney built onto the wall or keyed in every other brick?
     
  19. It does all seem to be a bit bizarre, Cath.

    The bracket is 2' wide? Is there any part of that stack that's only 2' wide, even if you go up further than you wanted?

    The SE told you where the bracket should go, yes? And where was that? How wide is the stack at that part?

    And where is the SE's recommended location compared to where you would want to put it?

    If where the SE said to position the bracket is wider than the actual bracket, and he's suggesting that the lintel on top will take up the extra required width, then that sounds to me - as a layman - a bit of a cobblers. Ie, I'd suspect he got his measurements a bit wrong, didn't make the bracket wide enough, but knows it'll be 'fine' so is hoping to 'get away' with it.

    (That's obviously chust a guess, of course).

    Because, why on earth would he design a bracket that was narrower than the breast at that point? Doesn't make sense to me.

    Ok, what to do? I think I'd call the BCO and run it all past him first. See what he says, and make your decisions based on that.

    What I would not do is fit the bracket anywhere other than where the SE said, 'cos he can then claim it doesn't conform with his specs.
     
  20. I am not a Structural Engineer and therefore I am only making my own observations of the job.
     

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