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Flat roof under-insulated?

Discussion in 'Roofing and Guttering' started by redcoatonline, 30 Apr 2019.

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  1. ban-all-sheds

    ban-all-sheds

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    Whether it is or is not reasonable is probaby not a profitabe discussion to have with Building Control.


    Who was the person who designed the roof and decided that it would comply?

    Who applied for Building Regulations approval?



    You should be asking these questions here:

    upload_2019-5-4_17-50-25.png

    not here:

    upload_2019-5-4_17-51-4.png
     
  2. durhamplumber

    durhamplumber

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  3. redcoatonline

    redcoatonline

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    A builder who specified the roof. I'm in contact, so expecting to have that discussion, but need to understand what BC might allow to resolve. There are several other issues too, but this is the main one.

    Thanks, didn't read the descriptions.

    Glad to hear this is a workable solution: it means the ceiling has to come down, but at least the roof can stay in place.

    My takeaway from all of this is to read the regs and not rely on the builder to do the job 'to spec'. It's frustrating that it wasn't done with enough in the first place, but lesson learned for next time. Hopefully I can sort something out with the builder and not end up in a dispute.
     
  4. Notch7

    Notch7

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    0.18u value for flat roofs has been the case for a few years. Most builders would know you need min 120mm /125mm for a compliant roof (depends on detailing).

    Your BC would be a bit mean if he didnt allow say 50mm in between the rafters.

    Is this a new extension or a replacement roof?

    With a SAPS test it may be possible to offset the 0.02u with some other improvement you may have done -like a new boiler or changing to led downlighters or new windows. Its a bit self defeating though, as a SAPS costs about £300 which you could towards the additional insulation......
     
  5. ban-all-sheds

    ban-all-sheds

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    Then it's entirely down to him to bear the entire cost of removing it and doing it again, properly, from scratch.

    Be very careful about going for any "hybrid bodges". Any solutions like that should be verified by an independent expert (again at the builder's expense). If you were to find, 10 years down the line, that despite all the wedging tight and taping you did have problems it would be too late.
     
  6. noseall

    noseall

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    There is no need to redo anything.
    There is currently 100mm of Celotex already above the roof. There will be no cold bridging. The 30mm between will merely be a supplement. All those roofs furnished with 100mm before Reg's asked for the 20mm increase are still doing ok.
     
  7. ban-all-sheds

    ban-all-sheds

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    I'm sure they are, but that's not the point.
     
  8. noseall

    noseall

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    BC will accept 100mm above + some between. No problem.
     
  9. noseall

    noseall

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  10. redcoatonline

    redcoatonline

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    As far as I understand it, there's virtually no way that 100mm would meet the requirements, and I've no doubt he was aware. Even if he's not aware, the job doesn't meet the spec, so he needs to address the issue.

    A replacement roof, but a conversion from garage to living space, so change of use applies.

    That's my hope, but after 2 e-mails and no reply, I suspect this is going to be hard work. I think the case is strong for him to bear the cost, but actually getting it resolved or paid for is another thing. Hopefully BC can apply some pressure (I think they can take action directly?).
     
  11. noseall

    noseall

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    HELLLOOOO?

    BC WILL ACCEPT 100MM ABOVE PLUS A SUPPLEMENTARY THICKNESS TIGHT UP AGAINST THE 100MM.

    Hope he heard me this time.
     
  12. Notch7

    Notch7

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    I doubt it. They just wont issue the final certificate.

    An experienced builder would know for sure.

    Was this done under a full building regs submission? If it wasnt how was tge spec agreed. Did the builders quote say 'compliance with building regs' or similar.

    If not, I wonder whether a breach of contract can be proven.

    I have known builders use say 100mm celetex, then keave sone off cuts of 125mm around for the building inspector to see.

    Its possible your builder placed the order but found there was only 100mm in stock and he didnt get the extra 30mm.

    I doubt there is much cost difference between 100mm and 120 or 125mm -so I doubt it was deliberate,
     
  13. redcoatonline

    redcoatonline

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    Thanks, I do hear you, but I'm not talking about what BC will accept, I'm talking about whether the builder knew that 100mm was too thin. That's important because it lets me build a case for reimbursement/ammendment against the builder.
     
  14. redcoatonline

    redcoatonline

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    I didn't submit a plan for work before the builder started, and didn't get BC to inspect the work in progress: I believed it was for the builder to comply with BC, and not my responsibility. That was my mistake and one I won't make again. I don't think I have any paperwork from the builder that says explicitly "this work will comply with building regulations", but surely there's a case to be made that if it doesn't comply, it's not fit for purpose?

    Latest update is: BC in-depth inspection is coming up, I've contacted the builder to see if he can attend, but I'm getting no answer.

    Thanks all for the input so far.
     
  15. ban-all-sheds

    ban-all-sheds

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    It was.
     
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