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Is this OK? Concrete floor install.

Discussion in 'Building' started by mrbiscuit, 11 Jul 2021.

  1. mrbiscuit

    mrbiscuit

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    I think I know the answer, but I need confirmation either way...

    I employed a builder to remove an existing timber floor in my 1890 terrace. This decision was carefully considered following some serious damp issues.

    Drains have been installed to remove water that tended to accumulate under the timbers due to a disparity in levels with the neighbouring house (see previous posts).

    However, we are now at the stage of laying the DPC and insulation. Let me list my concerns. Pictures are included for reference.

    1. At no point has the MOT1 hardcore or sand blinding layer been leveled out. A whacker plate was used for about 10 minutes on the hardcore layer, but not on the sand. As a result, the both the hardcore and sand layer is very bumpy and uneven.
    2. The builder purchased 120mm thick insulation boards. These are too thick to allow the correct level, and so he has attempted to cut them in half. As well as being messy and ineffective this has left the boards broken, uneven and with the protective layer on one side only.
    3. During works, a stud wall was propped up on blocks of wood. The wood sits on bare earth. He has cut the DPC around these block to fit...

    I'm becoming increasingly concerned of a lack of care and attention to detail. As I understand things, the hardcore layer should be level and completely flat before being blinded with sand. In addition, the insulation boards should have an intact moisture barrier layer on both sides and should lay completely flat on the DPC without any rocking. And I am sure that the blocks holding the wall shouldn't be like that.

    All thoughts and comments appreciated. It should be noted, that, in fairness, the builder walked out this morning and there was talk of "getting the right insulation", but my comments and concerns have not been answered by him, hence my post here.

    Rich.
     

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  3. Scarlet Pimpernel

    Scarlet Pimpernel

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    Five points:
    1. if the insulation is above the dpm, it doesn't need another protective layer as long as your builder positions a dpm above the insulation as well, but this second dpm can be thinner. It's to prevent moisture from the concrete pour seeping down the joins of the insulation. Normally taping the joints would have been sufficient.
    2. Your floor insulation is now not sufficient, I think.
    3, Your wall support is a nightmare and is liable to rot pretty quickly, unless your builder removes one support at a time and feeds the dpm under the wall supports, and properly seals the dpm. It will also need a great deal of attention with the second dpm layer to again prevent moisture from the concrete pour seeping down into the insulation.
    4. And yes the MOT should have been tamped to refusal, and level, and the sand tamped again. The idea is to get the smaller MOT particles, and the sand particles to permeate and settle between the spaces of the MOT, and to provide an even base for the dpm and insulation.
    5. Your builder has cut the insulation sheets into thin strips. They're normally 8 X 4 sheets.
     
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  4. mrbiscuit

    mrbiscuit

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    @Scarlet Pimpernel Thank you.
    He does plan to put another layer pf DPM on top, but with all the rocking around of the insulation on the uneven ground I don't know how they'll manage the pour and keep it intact, let alone stop the insulation cracking.
    The strips were cut there I think to allow fitting around the temporary wall supports.

    Sounds like I need to have a serious conversation with him about what happens next.

    Do you agree that the DPM should come up and at the very least the blinding layer tamped and leveled, and the wall given proper structural support?

    Rich.
     
  5. A Trowel

    A Trowel

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    You are of course aware that this work needs to meet current building regs and the prep work inspected by BCO prior to concrete being poured ;)
     
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  6. sxturbo

    sxturbo

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    Sack him before it's too late.

    I'd be almost tempted to do the prep work myself and just get someone in to do the screed work
     
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  7. mrbiscuit

    mrbiscuit

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    @A Trowel Thank you for that nugget. I will be calling building control first thing and asking them to make a visit.

    One question - Should I have been informed of this by my builder?

    @sxturbo I think you are right. I only employed him to do this because I had my hands full with other things. Ordinarily, I would have just had a good go myself. It was when I saw work being done that I could easily have done myself to a higher standard that I started to get dissatisfied.
    Anyhow, I've let home know that all work needs to stop until a resolution is found.

    This is 8 weeks in BTW. Sigh.
     
  8. A Trowel

    A Trowel

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    @mrbiscuit It’s your responsibility as the property owner to get Building Regs approval, but any decent builder would have pointed this out to you :(
     
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  9. sxturbo

    sxturbo

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    On the plus side the hard work of ripping the old floor out has been done, so hopefully it's just a case of prepping now.

    At least you have discovered this before work has completed, and can rectify for little if any cost.
     
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  11. mrbiscuit

    mrbiscuit

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    @A Trowel Am I going to get a slap on the wrist from the BCO or worse?
    @sxturbo Indeed. Job done properly and all that.

    Thanks guys, I'm feeling a little more positive about this now.
     
  12. sxturbo

    sxturbo

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    Bco will be fine, get them involved ASAP about now is when they would want to see it anyway
     
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  13. A Trowel

    A Trowel

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    As above
     
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  14. mrbiscuit

    mrbiscuit

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    Thanks for your input guys.
    I'll update when I have more news.
     
  15. mrbiscuit

    mrbiscuit

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    Quick update.
    I've voiced my concerns to the builder. Unsurprisingly the relationship seems to be failing.
    I spoke to building control as well this morning. They have the application and a site visit is being arranged. BC were super helpful btw, and have encouraged me to go ahead and do it myself.
    I'll tell you more when I know.
     
  16. Mr Chibs

    Mr Chibs

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    Good luck.

    I did my own, it’s quite straightforward you’ll be good with it.

    Best you get shot of the clowns.

    Out of curiosity, what’s the plan with the wood wedges holding up the wall? Take it these will be left it once the pour starts??
     
  17. mrbiscuit

    mrbiscuit

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    @Mr Chibs Thank you. I can't wait to get stuck into it.
    I'm no expert, but I'm guessing a small brick dwarf wall to hold it up. There's a staircase on the other side.
    The builder claimed this morning that he was going to take them out. I asked him why he turned my DPC into spaghetti in that case. I can't repeat the reply here.
    I'll ask BC what they recommend.
     
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