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General: Insulation and MVHR (Airtight) - Prices comments

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  1.  
    • CommentAuthormatyhaty
    • CommentTimeJul 19th 2014 edited
     
    Hi All

    Well after many a tweak, discussion and lots of learning on here, we are about to break ground next week.
    We have just had our quote back for the insulation.

    The insulation is expanding spray (or cavity expanding stuff).
    Would like to get peoples thoughts on the insulation, the prices and any comments.

    The house itself will be 50% old building (solid wall, and joining wall to ext door) and 50% new (cavity, vaulted cielings)

    I have removed the branding from the quote, just to protect anyone!
    They have helped us understand and get a green deal voucher, so as longas people think they are reasonable prices, then im cool.

    The MVHR, 3 options on there, which would you choose?

    Thanks to all
  2.  
    I can't find my magnifying glasses, and my ordinary glasses don't quite allow me to be certain of the figure for the porch roof. I think it says 0.298 (which sounds about right with a lambda of 0.025). I am not sure how that's OK 'with no further insulation required' as the regs (England, anyway) require 0.18.

    Also I am not clear how ''The cavity itself will be left empty'' when the quote is for CWI. Do you mean it will be built empty and retro-filled? Or do you mean that 60mm will be sprayed on the pre-built inner wall of a (say) 120mm cavity construction, laving a cavity outboard of the insulation?

    First thoughts are that if you are building (part) from scratch, can't you get lower U values?
    • CommentAuthormatyhaty
    • CommentTimeJul 19th 2014
     
    Hi Nick

    sorry epic fail by me! The cavity is not left empty, and will obviously filled with this stuff.
    The cavity is 75mm.
    Ive editted the orginal post!

    The U values, yes we were told that we could get lower, but using this we also get air tightness 'built in' and thus helps.

    How good or bad are the U values?
  4.  
    Well, the porch roof does not comply, unless, as a porch, it's outside Bldg Regs, but that doesn't explain the comment that ''no further insulation(is) required'', and te waall U value just meets the regs, at 0.27. many on here are looking for 0.1 - 0.15. Yes, air-tightness is good, but low U values and a/t even better.
    • CommentAuthormatyhaty
    • CommentTimeJul 19th 2014
     
    Hi nick

    Thanks for the advice

    Are there any products you would recommend, we still have the option to change this.
    (Well would need to know the cavity width pretty soon!)

    One of the key things is to get air tightness 'built in' as we dont really have builders with the expertise to do this

    Thanks

    (PS the company is solarcrest, and the green deal voucher as been assigned to them, but i believe we can change it)
    • CommentAuthorGaryB
    • CommentTimeJul 19th 2014
     
    Matt

    To enable assessment of the MVHR options, could you advise the number of wet rooms and the floor area of the dwelling?
  7.  
    Even if the porch, is outside Bldg Regs, I'd take issue with the comment that ''no further insulation(is) required''. Just because it is not stipulated does not mean it's not a good thing. Accepting that a porch may be as little as a wind-tight buffer-zone, if it's worth enough for U = 0.298 it's worth U = 0.18 or better.
  8.  
    I haven't missed any areas (m2), have I? We can't comment on the prices without knowing the £/m2.

    Nick
  9.  
    In 1988-1995 we were building houses with 150mm fully-filled cavities. 75 seems very skinny.Even if you go for pumped foam as an air-tightness 'tool', try to get the U value down significantly.

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