Lots of mould behind kitchen cabinets

Discussion in 'Builders' Talk' started by katyec, Jun 18, 2019.

  1. katyec

    katyec New Member

    Hello all,
    We perhaps moved into a house that has the worst extension built onto it.

    Theres absolutely no insulation on external walls and one side (which we cannot reach in any way) doesnt even have render on the outside, just exposed blocks!

    We just cannot understand how the type of extension built is allowed.

    There is a guarantee for a 'chemical' damp proof course replastering works until 2036.

    We have been struggling with mould growing into the cabinets for a while but seemingly at one point we felt we were on top.

    After a thorough inspection today we noted that the mould is the full length of our kitchen cabinets along the external wall and without taking out our kitchen there is not much we can do.

    My questions are:
    1) is this highly likely to be condensation
    2) would we get anywhere with calling on a guarantee? The plaster will almost certainly need chipping off and replastering.
    3) do we need to re-insulate the external wall? Would this be achieved through thermal boards inside a stud type wall?

    Thank you for your time
  2. koolpc

    koolpc Super Member


    Cold wall, warm air rests on it, boom! Lack of ventilation too.

    Only way would be to remove all the units, insulate the whole wall and put units back. I had this done in a bungalow. Cured it 100%. Studs with insulation and plasterboard on top. Other methods available too.
    katyec likes this.
  3. katyec

    katyec New Member

    What method did you use to re-insulate the wall please?
  4. koolpc

    koolpc Super Member

    Edited my post to say
    katyec likes this.
  5. CGN

    CGN Screwfix Select

    Could be a variety of factors at play.

    Often, with kitchen cupboards, mould is down to condensation and lack of airflow. I’m guessing, that it’s an older property with solid 9” walls and no cavity? If so, then the internal temperature of the walls will often be low enough to cause condensation. This is often misdiagnosed as ‘rising damp’, and so gets treated with a chemical dpc and ‘damp proof’ replastering up to a metre. It’s a big con, often does more damage and more than often doesn’t cure the problem. Check ground levels outside and make sure all drains are working properly, down pipes and guttering are in good condition before anything else. Check air vents are clear and unobstructed. Assess the ventilation in the kitchen too, as steam from cooking often a problem, and it has to go somewhere!

    If the mould is very bad (guess it is), then remove units, and plaster, insulate internal wall using either stud wall and insulation, PB, or use insulated PB, make good and reinstall, but make sure there is no penetrating damp from outside first and that you’ve done everything you can regarding ventilation.
    katyec likes this.
  6. katyec

    katyec New Member

    Thank you, our main house is Victorian Brick circa 1903 but the kitchen extension is from 2005 and is literally grey breeze block type with pebble dashing ( but only on one side the other has zero outside rendering)

    The wall in question forms the side of our neighbours garden, I'm not sure there is any ventilation bricks.

    Interesting you mention drains, we do have a blocked drain but this is 2m from the extension in the garden? Surely this is not contributing

    Thanks :)
  7. CGN

    CGN Screwfix Select

    Often when there is a blocked gully next to the house that can cause issues.
    Is it a cavity wall?
    katyec likes this.
  8. katyec

    katyec New Member

    No it's just a one width grey block wall
  9. CGN

    CGN Screwfix Select

    Ok, I’d probably go with a stud wall, celotex (or equivalent) and include a vapour barrier (polythene) in this case. You may want to think about putting either ply or osb on the studwork before PB if you have any wall mounted cabinets, or put in extra noggins to pick up the cabinet fixings.
    katyec likes this.
  10. Astramax

    Astramax Super Member

    If it were my wall I would remove the plaster and render and Synthapruv the whole wall and the insulate as CGN has suggested, can the out side of the wall be rendered?
    katyec likes this.
  11. katyec

    katyec New Member

    This side of the house is rendered and pebble dashed.
  12. katyec

    katyec New Member

    The wall area in question is 2.4m x 4.3m.
    Would it be cheaper to stud wall and insulate ourselves then hire a plasterer to finish?
    Does anyone know roughly what this would cost?
    Thanks :)
  13. koolpc

    koolpc Super Member

    Thats what i did.

    I battened the wall. Insulated. Put vapour barrier up. Plasterboarded. Then my plasterer came and plastered the wall. Cant remember exact costs. I know plasterer only charged me £90 to do the wall. Dimensions were almost same as yours except walls were 3mtr tall.
    katyec likes this.
  14. katyec

    katyec New Member

    Hi everyone, thank you for all your help.

    We have a plan to:
    1) Remove old kitchen
    2) Remove mouldy plaster work and treat
    3) Stud wall with thermal insulation and membrane
    4) plaster board and plaster
    5) New kitchen

    Only question is that we will have wall mounted cabinets, we will add extra wood to fix wall mounted cabinets but the fixing of these would surely pierce the membrane over the insulation?

  15. koolpc

    koolpc Super Member

    That shouldnt be a problem
    katyec likes this.
  16. Solidair

    Solidair Member

    Got a situation like the above, I'm going to try a similar solution. It's a victorian house but this is a new offshoot that a stonemason described as "single-skin brick externally rendered with a probably an early-ish cement from 40s or 50s cement"

    Have hacked off gypsum internally that was over a lime render where we were getting mould in one of the bottom corners and kitchen units (ruled out drainage/etc.) - planning now to put sheepswool insulation in studwork.

    Since it's single-skin brick with the external cement should I be looking for a permeable 'vapour control layer/membrane' or an actual 'vapour barrier' between the insulation and the internal plasterboard?

    Some people seem to use these terms interchangeably but from searching there seems to be a difference, not to mention massive range in products and prices from things like this on screwfix https://www.screwfix.com/p/capital-valley-plastics-ltd-vapour-barrier-green-300ga-2-5-x-20m/12869 (where people describe using it as basic dust sheeting aswell!) to products like Ampatex and Pro Clima Intello which are pitched more as 'smart' membranes.

    I want to make sure I get this right so I'm not ripping out a brand new kitchen again in a couple of years... (am installing new room ventilation aswell). Any advice would be appreciated and if there's a spec I should be making sure the membrane/barrier meets?

    Thanks in advance for any suggestions!
    katyec likes this.
  17. Solidair

    Solidair Member

    Morning, apologies for the bump, I'm trying to tackle this shortly so need to buy the materials today or tomorrow, just wondered if anyone might have advice on whether it's a 'vapour barrier' or a 'breathable' membrane/control layer I should be after and any typical spec that's recommended?

  18. Chriz1

    Chriz1 Member

    Or even fit a positive ventilation fan and help the whole house bit colder on the landing but makes a massive difference to the whole house,
    Cured my condensation mould
    Solidair and koolpc like this.
  19. Solidair

    Solidair Member

    Cheers, that’s what I’ve opted for. Went for a fan and a breathable vapour control layer in the end in case moisture ends up getting between the insulation and the exterior.

  20. Chriz1

    Chriz1 Member

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