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Please help! Potential structural issue in bathroom

Discussion in 'Building' started by SemiDeranged, 14 Jul 2019 at 8:59 AM.

  1. SemiDeranged

    SemiDeranged

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    Dear all, hope you're good. Also hoping you might be able to give me some advice here!

    About 5 years ago I bought two adjoining 1930s semis. I knew the previous owner, who had passed away. The kitchens are at the rear external corners of the building. One of them was converted by the previous owner to a wet room bathroom due to her illness for access. This entailed filling the back door (between the kitchen and adjoining garage) with breeze block at the outer brick course of the cavity wall.

    The upshot is that I have two bathrooms on top of each other, the lower one a wet room shower with a bath in the upper. Subsequent to some signs of damp in the walls of the lower bathroom and adjoining areas (bubbling paintwork), I decided to have a poke about to see if I could isolate the cause of the issue. In due course, I found that the ball valve on the upstairs bathroom toilet wasn't set right and was causing continuous runoff from the overflow pipe. Having remedied this, I set about cleaning the external brickwork and garage flat roof, over which the water had been running. The pointing looked suspect in places, with some small areas of soft mortar and visible cracking (not massive, see external pic). I thought I had isolated the source of the damp, since all of this was directly above the areas showing problems.

    I proceeded to strip what appears to be original lime/clay plaster from the bathroom to check the pointing, since it appeared to have some issues as mentioned externally. Of course this is now the inner course I'm working on. And to my horror, this is what I found when I exposed the portal (see pics). It appears that the inner course portal is supported by a wood lintel that looks original. It appears structurally decent. The portal face was covered with plasterboard and the whole skimmed to create the wall surface, which is what I've removed. However, there is a really nasty looking crack emanating from the corner of the lintel in a roughly vertical direction. This is what has me scared. The mortar around it is very soft to non existent in places - I could take it out with my finger. The crack is deep - see pic 2 with embedded plaster trowel to full depth. I didn't clear that out, it was like that. Worse, one of the bricks has cracked through the middle, suggesting significant loading to me.

    I think that two things may have happened: 20190714_080439.jpg 20190714_080943.jpg

    1) Penetrating damp causing over time softening and erosion of the mortar. Hopefully with fixing the external leak issue and repointing the bricks appropriately on the external course, the ingress will be greatly diminished and the wall can dry out, permitting me to address the problem with crack stapling and injection of fresh mortar into the joints.

    2) Movement of the 80+ year old wooden lintel, leading to the structural loading of the brick and its transverse failure.

    I am worried that there might be movement in the foundations - clay soil - but there are no other signs so I am hoping that it's one or both of the above issues. Does anyone have any advice or similar experience? I'm a professional engineer but not in structural (microelectromechanical systems) so I understand the physics and calculations but I am just an amateur when it comes to this stuff.

    Thank you so much for reading, any help would be greatly appreciated at this point. Can anyone suggest what the right course of action is? Am I right to be rather worried by this development? Can I just fill the mortar? Would you recommend replacing that lintel with a concrete one? Do I need to redo the brickwork?

    All the best.
     
  2. SemiDeranged

    SemiDeranged

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    Supplement: External pointing where continuous runoff from cistern had been running down the brickwork.

    20190714_081311.jpg 20190714_081328.jpg
     
  3. HERTS P&D

    HERTS P&D

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    Looks like your overflow is leaking.

    Andy
     
  4. Notch7

    Notch7

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    Timber lintels in older houses are pretty common its not that big a deal. Its probably best to replace it, especially if it could be weakened by rot.

    Im not sure what you mean by portal -the lintel carries all the load to the brickwork either side, the door frane isnt carrying any load.

    I wouldnt be worried about subsidence, the house is 90 years old, itll still be standing in 90 years time.

    The flat roof flashing isnt too clever.......
     
  5. SemiDeranged

    SemiDeranged

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    Thanks for the responses, guys. Herts P&D, the overflow was leaking, yes - I fixed it, and found the pointing was wanting externally (as seen). That was when I decided to investigate the other side, where there was bubbling paintwork, and found the crack. Notch7, by "portal" I just meant the physical gap in the brickwork, the old door. I get that the lintel acts as a beam under transverse loading to transfer the load to the brickwork. The flashing was buried under about 3 inches of soil and various plant growth until I cleared it up a few days ago, which led to the present situation. Hell of a mess :)

    This was clearly an old issue - there was a crack in the original plaster that had been backfilled 10 years ago when the wet room was converted, so it is at least that old and probably a lot older - appears relatively stable. I'm wondering if I would have been better off letting sleeping dogs lie, but I would really like to put a long term solution in place here, not a quick fix. I'm thinking Acrow props to support the potentially unstable lime mortar brickwork, then concrete lintel in, and repoint / inject new mortar, with crack stapling using helical stainless rebar to secure the joints. I need to further investigate the continuation of the cracking above the ceiling level, which is obcured on the next floor by cladding, which I'll have to take out. I may need to remove the floor/ceiling for access. I will either undertake to replace the brickwork if it appears necessary, or call in a professional if the work is beyond my comfort level.

    Thanks for your advice so far, everyone. Any other opinions or further suggestions would be much appreciated.

    Best wishes.
     
  6. Notch7

    Notch7

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    A steel box lintel might be easier to fit than a concrete lintel -much lighter to lift and maneuver into position.
     
  7. SemiDeranged

    SemiDeranged

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    Cheers for the help, N7 (y) Someone else mentioned using steel angle or a rolled I-beam joist when I posted this on Reddit. The idea of supporting it with brackets occurred to me - seems it would spread the load further but would somewhat weaken the masonary due to the drilled bolt holes. This makes sense to me as an engineer but I have no specific experience with this. It would create lateral loads on the brickwork as well as bending moments - I know masonary likes compression a hell of a lot more than tension so perhaps this would be counterproductive?
     
  8. Notch7

    Notch7

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    ive just looked at the pics on a bigger screen -am I correct in saying this is blocked up doorway that led through an external wall into a garage?

    I wonder if the problem is water getting into the cavity and running down -maybe due to the overflow.

    this is a typical box lintel (Im not sayings its suitable for the loading in your situation).
    https://www.condell-ltd.com/ig-lint...Mb98UzmHTGIPabh7vjEVk4rUqDQRZb4gaArRwEALw_wcB
     
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  9. SemiDeranged

    SemiDeranged

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    I see! This is a lot lighter (and cheaper) than the stuff they put in the loft - was a serious I beam welded from plate steel, I'd guess about 8mm of it on the flanges. Was heavy. Thanks a lot, again.

    That is right, yes. You can see the blocked up doorway on the outer course - which is breeze block or similar large format - and also the lintel and part of the opening on the inner course of brick, as well as a "door frame" that is not original and I assume was put in with the wet room. I put my phone in the void and used the flash to take a load of photos - appears that the cavity is (somewhat) isolated from the door gap by timberwork inside the wall, which looks to be intact enough, although not at all pristine. I had wondered if that might be related.

    My current theory (fwiw) is that something along those lines must be, or at least is very likely to be, happening - it's good to hear those more experienced think that this may be plausible. It is possible that the outer wall issue is unrelated in theory - and complicated by the fact that the downstairs room is a wet room shower and sees internal humidity - but they are so close together and it's so specific ( there is one other patch of damp on the other side of the transverse internal wall and the rest of the house, including the other walls in the same wet room, are bone dry - thanks old plaster!) that I feel like it has to be related. I know for a fact that there was running water on the external brickwork for years, constantly. I also know for a fact that the pointing is weak where that happened - mostly it remains hard but there are deep cracks and gaps, I'm sure ingress has happened there. It is about 3 feet directly up from the crack bottom - 18 inches above the ceiling in the wide angle photo of the crack. I wonder if a wall tie or other structure could be responsible for water crossing the cavity, or if general dampness, puddling at the bottom, etc. would be sufficient to cause this issue on the internal course?
     
  10. bobasd

    bobasd

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    it looks like you have a redundant doorway on an external wall.
    the opening was framed with 2x backing and plasterboarded.
    the stout lintel above the opening appears sound.
    if you think support is an issue then: after removing the 2x's the opening could be bricked or blocked and the lintel eliminated?

    or you could replace the lintel - though i see no need for replacement unless there's some heavy point load directly above.


    where you have bubbling plaster or other cracks then pics please?

    fwiw: the crack above the lintel could have the beds and perps raked out and pointed up with a 3:1 mix of sand and lime - or even remove and re-bed the bricks.

    to stop water tracking back, fit a 90 degree fitting on the end of the overflow .

    sometimes, in spite of cavity walls, water can still penetrate and show on the interior surfaces:
    your flat roof covering is laid wrong direction with a poor attempt at any flashing including the soil pipe - water will possibly be penetrating at the wall/flashing on the left.
    on the right hand house: its a poor arrangement where the roof gutter is flashed - there's possibly moisture penetration into the other house?
    the flat roof is due for renewing with a different arrangement to falls with a gutter at the back elevation not the side.
     
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