Damp Proofing Question

Bathroom mould/mildrew - damp


I live in a ground floor flat, within the bathroom I have a constant growth of Mould and Mildew and if it is not cleaned on a regualr bases then it keeps re-surfacing.

I have added an Extractor in the bathroo, but does not seem to have made much difference. I have also used Mould Mildew spary to kill the bacreria which seems to work for a 1 or so then the black spots re-appear.

Is there something I am able to do with out any building work on the outside ?
I have not tried the paint which could also remove this problem but feel that its not going to work.

As I live flat, the building is onwned by the local council, but manority of the people living in the flats are private oweners or tenants. Is this a problem the council would need to look into if the outside walls are affected with being damp ?

Any help and advise would be great,

I am based in the HA5 area of North West london



7 Answers

Best Answer

best way to cure excessive moisture in bathrooms/kitchens is not extraction,but input ventilation which will cure the air.
I recommend you take your extractor out and replace with a Heat Recovery Ventilation Unit.
Here is a link which will give you an idea what they are,what they do and the one you need.


If you go on ebay,you might be able to pick one up quite cheap.

Unfortunately,i can't say for certain if this would be the councils responsibilty or yours but i'm sure someone on here could point you in the right direction on this.

Hope this helps,


Answered 10th Apr 2011

carl melady

Member since 1 Jun 2008

I have been involved with damp proofing for almost 30 years and more and more condensation is becoming an issue due to lack of ventilation. Years ago properties had more natural ventilation ie open fires and badly fitting doors and windows . I tried all sorts of cures from extractors to dehumidifiers but the best by far are Kair heat recovery ventilators (i-sells.co.uk) they cost around £350.00 or £550.00 fitted but are excellent and will stop the problem straight away you still have to do a final clean of the mould but it will not return as the source of moisture has gone

Answered 11th Apr 2011

SL solutions

Member since 29 Jan 2010

Hi there, it's hard to say whether it is penetrating damp from a gutter, downpipe etc without looking at it,or rising damp from a membrane breakdown. Condensation and blackspot come from cold damp areas that are unventilated. It's local authority owned so get their building surveyor to inspect and act on the repairs. Remember prolonged exposure to this type of fungus bacteria can cause health problems.

Answered 10th Apr 2011

Pro Finishing Services

Member since 12 Jan 2010

One of the causes of Condenstaion is cold surfaces and it may be that the walls are not insulated (This is putting it very simply). To control it you need to have good ventilation to allow the moisture laden air to escape so after a bath or shower, try to ventilate the room to the outside, not to the rest of the house.
Also the warmer the air the more moisture it can hold so the Bathroom also need to be heated.
Fixing treated 25mm x 50mm battens to the walls and infilling between with 50mm Celotex or similar and then overboarding with Duplex (foil-backed) plasterboard and skimming should improve things as far as insulation goes. - just opening a window (and closing the door) will help.
If you want to repaint you could use 'FUNGI-CHEK EMULSION' from Sovereign Chemicals or similar. They say "This is a high quality acrylic emulsion paint containing a powerful fungicide, ideal for use in Kitchens and Bathrooms where the effects of condensation are more prevalent. Suitable for walls and ceilings where mould growth is a problem. Fully washable and guaranteed to offer long term protection against black mould and mildew. Available in white and magnolia. Areas to be treated must be fully cleaned prior to application using either Sovereign Scrub Out Black Mould or Sovereign Dentolite"
The link is http://www.sovchem.co.uk/condensation-control/mould-control-products/fngi-check-emulsion.html
Hope this helps

Answered 10th Apr 2011

Tony Browne General Building

Member since 2 Feb 2010

In my experience the only way would ba a permanent source of ventilation or try removing all the infected plaster treat again. With damp and mould sealer then replaster and paint

Answered 10th Apr 2011

Complete General Builders

Member since 25 Jun 2009

hi,the mould is formed by condensation when warm moist air meets a cold surface, could be that the outside wall has no cavity(9 inch wall) or cavity insulation,has the fan you fitted got an overun timer? this allows the fan to run for a set time after you have finished in the bathroom allowing for all the moisture to be vented,if the fan is wall mounted has it been fitted corectly - not too high,.regards Terry.

Answered 11th Apr 2011

tm property services

Member since 9 Mar 2011

contact Wykamol or look on the website under Wykamol condensation

Answered 10th Apr 2011

Building services

Member since 18 Dec 2010

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