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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorwholaa
    • CommentTime3 days ago
     
    Hi,

    I have a 2016 built semi D Irish house. It has double leaf cavity walls with drywall. In a few spots I have been able to see the behind the drywall and see holes in the inner leaf for electrical wiring. The inner leaf is parged but surely these holes allow huge amounts of cold air to enter and chill the back of drywall (see figure). Is it worth my while cutting holes in the dry wall and filling the leaf holes?
      cold bridge.jpg
    • CommentAuthortony
    • CommentTime3 days ago
     
    I have been on this problem for over twenty years now, nothing has changed in site practice, some progress on what should be done

    https://readinguk.org/draughtbusters/finding-draughts/dry-lined-homes/

    Plenty of info on DraughtBusters website

    https://readinguk.org/draughtbusters/going-further/dot-and-dab/

    https://readinguk.org/draughtbusters/going-further/first-floor-void/
    •  
      CommentAuthordjh
    • CommentTime3 days ago
     
    Posted By: wholaaThe inner leaf is parged but surely these holes allow huge amounts of cold air to enter and chill the back of drywall (see figure). Is it worth my while cutting holes in the dry wall and filling the leaf holes?

    I would say so, yes. I'd be pleasantly surprised if electrical cables are the worst holes you find. Seal them with a specific airtightness product if you can - something that will remain flexible.
  1.  
    Bit odd to have wiring running through the cavity (how did it get fitted there?) and to have cold air circulating on the 'warm' side of the cavity insulation.

    Are you in contact with the builders, ask them to explain what they were thinking, any kind of guarantee?
  2.  
    Welcome Wholaa.

    W-in-A said: "Bit odd to have wiring running through the cavity (how did it get fitted there?) and to have cold air circulating on the 'warm' side of the cavity insulation. "

    Now don't mistake me for a fan of cavity walls, cavity insulation or the level of care often taken in installing cavity insulation, but *in theory* the insulation is fitted (and taped at every joint and perimeter....) tight to the internal skin of block. Now let's forget cynicism about the smoothness and 'clean-ness' of that bock face for a minute, but the major issue seems to me (and already to W-in-A) that, as drawn, the insulation is in the wrong place. Is this just the drawing, or the concrete (sorry!) fact?

    I am not familiar with Irish Bldg Regs, but in England the unfilled part of the cavity (a) would be on the outside and (b) would be ventilated, making all the tightness and taping all the more critical because of the risk of cold air getting past the insulation layer and onto the 'warm side'.

    If wiring is running in the cavity, then it really does sound like it's built as you have drawn - with the unfilled cavity on the inside - but that's not a lay-up I am familiar with.

    All of that notwithstanding (that's sitting down), if (a significant amount of) cold air is circulating on the 'warm side' you have much more of a problem than a few holes to fill. Can you clarify?

    Thanks,

    Nick
    • CommentAuthorwholaa
    • CommentTime3 days ago
     
    Thanks for the comments. I can only see in a small number of the holes. I have no idea if the cavity of the semi cavity double leaf is on the inside or the outside. All I know is there is there some wires running into the holes. The holes are too dark to see any of the 110 Quinn insulation boards that are supposedly inside.

    I was thinking of buying a Walabot and finding these in the rest of the house and filling them with cement but I will look into airtightness products. I am bit concerned about running the rather nice skim work though.
  3.  
    'Rather nice skimming' is a mere transient moment in the cold or warm lifetime of your house!!

    Perhaps a bit more research is required before I (and others) encourage you to start ripping big holes in the fabric.

    You write:''The inner leaf is parged but *surely* (my emphasis, NP) these holes allow huge amounts of cold air to enter and chill the back of drywall''.

    Those of us with time-served weariness of massive thermal by-pass jumped to the conclusion (well, I did) that you said: ''these holes allow huge amounts of cold air to enter and chill the back of drywall'', when actually I think you haven't experienced that yet, and are asking ''*will* these holes allow huge amounts of cold air to enter and chill the back of drywall?''

    'Research':

    1. Wait for a windy day. Open up enough of a hole in the plasterboard to allow you to get the (slightly moistened) back of your hand against one of these hols in the blocks. Can you feel the cold?

    2. Augment that 1st stage with an infra-red thermometer, and take readings at and around the hole, and do so for comparison on a still day too.

    3. Consider repeating the exercise for other such holes if the results of 1 and 2 suggest that you do have cold air in there.

    4. (Maybe this should be (1), but I cannot be bothered to re-number!) Can you find out where those cables are going?


    … and Hallelujah that it's parged at all!
    • CommentAuthorwholaa
    • CommentTime2 days ago edited
     
    Posted By: Nick Parsons'Rather nice skimming' is a mere transient moment in the cold or warm lifetime of your house!!

    Perhaps a bit more research is required before I (and others) encourage you to start ripping big holes in the fabric.

    You write:''The inner leaf is parged but *surely* (my emphasis, NP) these holes allow huge amounts of cold air to enter and chill the back of drywall''.

    Those of us with time-served weariness of massive thermal by-pass jumped to the conclusion (well, I did) that you said: ''these holes allow huge amounts of cold air to enter and chill the back of drywall'', when actually I think you haven't experienced that yet, and are asking ''*will* these holes allow huge amounts of cold air to enter and chill the back of drywall?''

    'Research':

    1. Wait for a windy day. Open up enough of a hole in the plasterboard to allow you to get the (slightly moistened) back of your hand against one of these hols in the blocks. Can you feel the cold?

    2. Augment that 1st stage with an infra-red thermometer, and take readings at and around the hole, and do so for comparison on a still day too.

    3. Consider repeating the exercise for other such holes if the results of 1 and 2 suggest that you do have cold air in there.

    4. (Maybe this should be (1), but I cannot be bothered to re-number!) Can you find out where those cables are going?


    … and Hallelujah that it's parged at all!


    Thanks. I will try this, there was wing blowing through some of the power sockets until I sealed them. It is very hard for me to say where the wires go but they come the power outlets, and but one from the kitchen plumbing. is that normal?
    • CommentAuthorbhommels
    • CommentTime2 days ago
     
    I would wait for that cold, windy day Nick is referring to, crank up the heating and then go around the inside with an IR camera.
  4.  
    The house was built 3 years ago. Does it have a warranty? (Yes.No: T.B.C.) Is it behaving as designed? No. It leaks cold air. Is it therefore of 'merchantable quality'? (Does the Sale of Goods Act - or equivalent - apply to houses? I suspect not.)

    I realise that is very simplistic, and that warranties are only any good if you can make them stick, but have you been in touch with the original builder to explain and discuss the issue? Cold air via the sockets is sadly not rare, but it is undoubtedly not right!

    Can the contractor explain why cables run in the cavity? Does (s)he know that they do? Can (s)he comment?

    And while you are waiting for that to work.....

    Cut out a minimum 150 x 150mm of plasterboard at each cable-hole. If you use a very sharp Stanley knife and bevel the cuts you will have 'plugs' that you can glue back in.

    Get yourself an offcut of EPDM rubber roofing, and some air-tightness tape (or buy these ready-made grommets: https://www.greenbuildingstore.co.uk/products/pro-clima-kaflex-cable-grommet/) and primer, and an electrician. Take off the sockets/switches as required, prime the parge-coat, wait till primer is tacky, and slide grommets over the cables. One grommet per cable! But if you make your own, as per my pic, you can make a 2-hole grommet. If you share 2 cables to one hole (as I have seen done) it won't be air-tight.

    And repeat....

    This does not cure the more fundamentally-worrying issue that there is cold air on what is supposed to be the warm side of the insulation, so do the consultation with the builder first.

    I wish you the very best of luck.
      DSCF6805 - Copy.JPG
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