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Damp Proofing

Damp patches and black spots on the wall

We bought our 2 bedroom house last July 2012. We noticed to the one room we are using is having damp patches on the wall by the window and to one side of the room, some of the patches are developing black spots, started when the weather get colder and worsen by winter. The new paint was ruined as elevating. I'm quite disappointed as we don't know what to do to stop it and who to contact to solve it. I searched the internet the possible cause and it looks like condensation. Is there a connection that our house has no exhaust or because its flat roof?is it condensation or any problem? Please help.

2 Answers from MyBuilder Damp Proofing Specialists

Best Answer

Hi there
definitely sounds like condensation cold walls condensing the warm air causing wet walls with then produces the mould,you need to manage the moisture in the property keep kitchen doors closed when cooking ,bathroom doors closed when in use this is all done to stop the moisture moving around the property
then you need to look at the ventilation in the room as you also need an airflow to remove moisture,when this has been done you can use anti mould paints to stop the mould ask at a professional decorating supplier for products
some properties are prone to condensation because of the lack of thermal materials used in the construction.if you need to seek a professional then it would be a damp company.


Answered 17th Jan 2013

Condensation accounts for approximately 70% of reported domestic damp.

Condensation can commonly be attributed to a lack of balance between heating and ventilation resulting in a rise in relative humidity. Air can hold more water vapour when warm than when cold. When warm air is cooled, such as when the heating system is switched off at night, it will deposit the water that it can no longer retain as condensation on a cold surface.

A similar effect that can be demonstrated by breathing onto a mirror or other cool surfaces. In its less serious form, condensation may “steam up” windows and mirrors.

In more severe cases, it can be absorbed by surface wall finishes and underlying plaster causing dampness although the underlying brickwork or masonry will normally be of a lower moisture content. It may cause mildew on fabrics and leather and, in extreme cases, can cause walls to be visibly wet. It is frequently accompanied by mould growth, of which the most common is “black spot” – a mould which appears first as small soot-like spots, and which can join up and cause large black areas. Condensation may occur at any height on almost any cool surface.

Condensation damp permits fungal growth. Materials such as wood, paper, wallboard, ceiling tiles, furnishing fabrics and even masonry and plaster can provide nutrients sufficient for mould growth providing the controlling factor is present i.e. the availability of sufficient moisture.

As "plasterworks" says above, it would be in your interests to seek a professional opinion.


Answered 17th Jan 2013

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