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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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    • CommentAuthorborpin
    • CommentTimeMay 11th 2023 edited
     
    https://www.bbc.co.uk/news/uk-scotland-glasgow-west-65543897

    My take is that the whole building would have been damp before the insulation was fitted. Once fitted, the inherent dampness couldn't escape causing the issues.

    I suggest that, once installed, the whole building needed to be subjected to intense de-humidification and then small dehumidifiers fitted to maintain the RH (as folk tend not to ventilate sufficiently).
    •  
      CommentAuthordjh
    • CommentTimeMay 11th 2023
     
    There's not really enough information in the article to understand exactly what's happened, but it seems like insulation without thought to ventilation is probably a major cause of the problems. I don't believe in dehumidifiers, I believe in adequate ventilation. Publically-funded insulation schemes should include and mandate it. And there needs to be an education campaign.
  1.  
    There are some windy rainy zones around the N and W of UK where CWI is not recommended, as the cavity is needed for its primary function of drainage.

    I would guess that East Kilbride (and Glasgow generally) might be in one of those zones.

    Edit: yes E Kilbride is in high exposure zone 4 so CWI only suitable in special circumstances. Maps available online (oddly, in English building regs but not Scottish!). Installing and then removing CWI has perhaps left the cavity bridged and spoiled the air and water flow routes through the cavity?
    • CommentAuthorborpin
    • CommentTimeMay 12th 2023 edited
     
    Posted By: djhI don't believe in dehumidifiers, I believe in adequate ventilation.
    Yes, but if you cannot be sure the occupnts will ventilate, then there is a need for dehumidifiers.

    Also, the initial de-humidification to remove years of dampness in the building fabric is vital, just like it often is used in new builds. To my mind, this is the key issue here.

    I'd also cite the situation of a relative in a student flat. No amount of ventilation worked - a small dehumidifier has worked wonders.
    •  
      CommentAuthordjh
    • CommentTimeMay 12th 2023
     
    Posted By: borpinYes, but if you cannot be sure the occupnts will ventilate, then there is a need for dehumidifiers.
    If they're not going to ventilate, why on earth can you assume they will use the dehumidifier? One involves actively defeating a system that is wired to run permanently and requires no action normally; the second involves actively switching on a noisy device and tending to it.

    I'd also cite the situation of a relative in a student flat. No amount of ventilation worked - a small dehumidifier has worked wonders.
    I'd be interested in the details.
  2.  
    Think its a balance : depends how dry the outside air is that you ventilate with (IE how many kg of extra water it has capacity to absorb); versus how many kg of water are getting into your home each day and needing to be removed; versus how dry do you need the inside air to be to avoid mould on the coldest surfaces in your home.

    In that part of western Scotland the outside air is usually very humid 80%+; a home with bridged/blocked cavities will leak in many kg of wind-driven rain; and with insulation botched then removed the surfaces will be cold. So no amount of ventilation is going to dry that out. Needs dehumidifiers, or a lot of heating, or EWI.

    Whereas in Eastern England or Scotland, in a watertight and insulated home, just ventilation with dry outdoors air can easily keep on top of the moisture load.

    Horses, courses, etc.
    •  
      CommentAuthordjh
    • CommentTimeMay 12th 2023
     
    Humidity varies throughout the day as the temperature changes and there is a reasonable diurnal range over the whole of Scotland. Nowhere in Scotland is listed as having a muggy climate at any time of year.

    And please remember the context. We're discussing failed insulation schemes, which were implemented without adequate ventilation, and perhaps incompetently as well. If the scheme had been carried out well then ventilation would be correct.
  3.  
    Not sure if you've been to East Kilbride, but it certainly is 'muggy' ! There's over 200 days of rainfall each year round Glasgow, much of it horizontal, compared with 100-120 days in East Anglia. The difference in climate has to be lived in to be believed.

    Edit: here's one of those risk maps for CWI mentioned earlier - "X marks the spot"! The scale is >100 litres windblown rain per m² of wall, so if even a small % of those litres are being bridged across the cavity by bodged CWI, then no realistic ventilation will be able to dry it.
      Screenshot_20230512-115930~2.png
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