Advice following Lintel replacement

Discussion in 'Builders' Talk' started by Chris Stevens, Aug 11, 2014.

  1. Chris Stevens

    Chris Stevens New Member

    Hi,
    I'm after a bit of advice so I have more confidence in what i'm saying to my builder following a lintel replacement.

    As part of an extension a lintel was removed and replaced with a longer Catnic type. The floor joists for the first floor are supported on this wall above the lintel on a course of brick and block. The extension is complete and the builder has been gone for a couple of months. During the renovation of the existing room that the lintel was in i have had the ceiling plasterboard down which has exposed where the 1st floor joists go into the block work.

    When the house was originally built there was a DPC layer laid along the block under the joists. The result is that the blocks below the joists were not stuck to the blocks above. This has resulted in a gap forming below this DPC. The joists have followed this and dropped as well, resulting in a gap on top of the joist (where mortar once rested on the joist). At the worst point i can get the end of my index finger into the gap above the joist.

    Upstairs, the floor has noticeably dropped, its a bathroom with a lino floor which was siliconed in the corners - so the silicone has stayed stuck to the wall and the lino has dropped by, at the worst bit, around 10mm - which ties in with my findings downstairs.

    I guess my bottom line question is: Is there an acceptable amount of drop expected from a first floor joist / flooring following a lintel replacement?
    In my eyes, this should be zero - is this too ambitious? 10mm seems a lot.

    Before I get my builder back and insist on them rectifying this I just want to get my facts straight.

    If you need me to sketch something up, I can. Many thanks in advance.
     
  2. Phil the Paver

    Phil the Paver Screwfix Select

    Photo's would be better, I'm intrigued by this DPC that's in there.
     
  3. Chris Stevens

    Chris Stevens New Member

  4. vivaro man

    vivaro man Active Member

    Chris, no deflection is really acceptable especially where there is support provided by a lintel. Is there any wall movement or cracks in the plaster? If there's a deflection of 10mm at that place then get the builder in and show him what's happened. Do it now. You've exposed the issue and know I would want to put the problem right.

    One thought occurs to me, have you had any issues with leaking water? Better to find out now than let the builder find it.

    Good luck.
     
    Chris Stevens likes this.
  5. Chris Stevens

    Chris Stevens New Member

    Thanks Vivaro man. That pretty much sums up my view of it. No cracks have appeared in the wall above, its tiled so it would be in the grout lines but there is no evidence of movement there. I've not had any leaking water and with the recent weather I think it would have come through if it was going to. On the other side of this wall is the extension and a flat roof felted up the wall and into the mortar. That outer skin hasn't moved (partly due to no DPC and partly because the ledger beam was already in place above the opening which gave some support)

    I've attached a picture for anyone interested. You can see the gap just above the DPC layer that the joists sit on.
    I guess the DPC sags a little from when the original builders leveled the joists.
     

    Attached Files:

  6. Phil the Paver

    Phil the Paver Screwfix Select

    The reason I said I was intrigued by the DPC in there was as you pointed out with your link, that it is a cavity tray over the existing lintel, this should have had weep holes built into the brickwork just above the exisiting lintel.

    Now you have had a new lintel fitted and in fact a extension with a flat roof built, where does the cavity tray now drain??, has the builder fitted a new one higher up in the cavity with new weep holes that come out above the new felt upstand.??

    This is why photo's are a good why of showing what has happen, unfortunately the photo posted doesn't show us a lot in terms of the construction around the new lintel.
     
    Chris Stevens likes this.
  7. Chris Stevens

    Chris Stevens New Member

    Yeh - sorry about that, I took a couple of other pics but they were hard to gauge the angle they were taken at due to pipes being in the way etc, and the other side is plastered in now.

    You raise a very good point, something I hadn't considered, there is no drain for the cavity tray and no weep holes above (i don't believe there were any on the existing house either). Any moisture within the cavity above would come down and onto the new lintel and either run along to one end and continue down the cavity or, more likely, soak through the bricks and through the wall into my new extension.
    Is this something that is covered by building regs? or is it just best practice?

    I'm drifting from my original question, which I have an answer to now so thank you. I'll get my builder back to sort it out.
     

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