Condensation and Mould Control

Dan R
Dan R
Homebuyer, Newton Abbot, Devon
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...efficient, professional and extremely friendly. He explained the potential issues and within 36hrs sent me a detailed report that explained the issues present. I would absolutely recommend this company!
Homeowner, Devon
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....punctual and professional and provided not only a comprehensive report but also was able to offer the solution. I strongly recommend Damp Genius if your looking for an honest and professional assessment.
Homebuyer, Devon
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Tom was great. Provided a comprehensive, clear report. Really thorough, professional and helpful. Would definitely recommend.

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Effective condensation and mould control can be frustrating to get right. So many factors come into play such as the relative humidity, the temperature of the walls, what the walls are made of and how the property is lived in.  Most people will be familiar with seeing some minor condensation on a bedroom window in the morning, however, in some instances, large amounts of condensation can cause heavy mould growth that is damaging to health.

Condensation forms on walls and windows when warmer moist air comes into contact with a colder surface. If the surface is cold enough then the water held in the air falls out (condenses) onto the surface. It is this pure water that the mould loves to grow on.

In the picture you can see that the black spot mould has formed on the colder sections of roof between the timber joists above. Our inspection in the loft found that this area was not insulated – the solution was simply to install more insulation in the loft.

Understanding the complex interplay between temperature and ventilation is key to getting the problem under control and often the basic advice of “keep windows open” or “turn up the heating” don’t really cut the mustard. 

A good understanding relative humidity is useful for any homeowner or tenant so have a read of this article before going much further.

Black mould formed on the cold spots between joists above

Is Condensation Mould Harmful?

Yes. Inhaling mould fragments or spores can inflame the airways, causing nasal congestion, wheezing, chest tightness, coughing and throat irritation.

Long term exposure to high levels of indoor dampness and mould can reduce lung function and aggravate chronic health problems such as asthma. People who already suffer from asthma and allergies are more likely to have severe symptoms when exposed long term to damp and mouldy buildings.

According to the World Health Organization (WHO), a large number of the world’s 300 million cases of childhood asthma are attributable to exposure to indoor dampness and mould.

How Do You Treat Condensation Mould?

Mould loves to grow on the clean, pure water which comes from condensation. The solution to the problem is therefore to prevent condensation occurring in the building.

The trouble is that stopping condensation forming is often tricky to do since it is affected by so many different factors. The things which influence the level of condensation in a building include:

  • Wall temperature
  • Air temperature
  • Amount of natural ventilation
  • Amount of mechanical ventilation – is there a PIV System installed?
  • The number of occupants
  • The number of times the doors are opened and closed in a day
  • How much insulation is in the walls/floor/loft
  • How many pets in the house
  • The types of windows fitted
  • The heating system installed
  • The number of bathrooms
  • Whether the walls are papered or painted (yes, seriously!)

And on and on the list could go.

The key metric which determines if condensation and therefore mould forms on a wall is the Dew Point. This is the temperature at which water will condense out of the air. For example a bedroom may have a Dew Point of 14degreesC and any surface below that temperature will cause the surrounding air to condense out the water.

To treat condensation mould requires a combination of better heating or better ventilation to bring down the humidity levels. This can be done by opening windows and keeping the radiators on but in truth it is very hard to get the balance right.

condensation and mould control with thermal imaging

Thermal imaging cameras are useful tools to identify any cold spots which may be leading to condensation and mould problems.

The picture here shows a thermal image within a photo of the ceiling in a stairwell. The image highlights a dark blue/light blue cold spot in an area where the client reported peeling paint and mould. This led to some further investigation in the loft void and after some digging around we discovered a steel beam directly above the cold spot. This meant the area was not insulated like the rest of the ceiling and with the plasterboard ceiling in contact with the steel it created a cold area prone to condensation and mould. Since moving the steel was not realistic we recommended a thermal paint be used on the ceiling to raise the temperature without needing any structural changes.

How Damp Genius Solve Condensation Mould Problems

We use a holistic approach to treat mould in the South West. First off a full and detailed survey is required, using specialist survey equipment to record the relative humidity, the amount of mould, it’s location and temperatures.

Using the results of a full detailed condensation mould survey we can then engage with a number of different treatment options designed to suit your needs and budget.

Mould Wash

A professional deep clean for your home or property. Damp Genius use a three part system that includes:

  • Walls/ceilings are washed down using high quality, commercial grade, anti-mould products. All black spot mould buried in the plaster is killed.
  • Next an anti-mould bonding solution is applied, sealing the wall to prevent mould entering the wall or ceiling surface again.
  • Finally a fungicidal/anti-mould paint is used to redecorate the area. This can either be the standard white emulsion or we can also add anti-mould to any paint of your choice.

For problem properties we find that improved mechanical ventilation is the gold standard for clearing up condensation and mould problems long term. 

PIV (Positive Input Ventilation) Systems work by trickling air into the property at a constant rate which gently forces any humid air out through the natural air gaps around windows and doors. 

Insulate Problem Areas

We know that condensation moulds form on colder surfaces therefore we are able to effectively insulate walls or ceilings to warm them up, reducing the chance of mould forming. Damp Genius use thermal paints and/or insulated plasterboard to achieve this. Every property is unique and a full survey will be used to determine the best course of action.

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