Condensation and Mould in Yorkshire Homes

Condensation is a common problem in Yorkshire homes that can cause a range of issues if not addressed promptly. Essentially, condensation is the formation of water droplets when warm, moist air comes into contact with cold surfaces.  There are a number of things that can cause condensation issues, including poor ventilation, inadequate insulation, and even drying clothes indoors. 

When condensation forms in the home, it can ruin interior decoration, cause an unpleasant smell and provide a source of sustenance for mould on walls. Additionally, high humidity (a cause of condensation) can impact the health of property occupiers. It may indicate that the air quality in a home is inadequate, having a negative impact on health. Homes which suffer the effects of condensation are equally likely to experience some form of black mould growth, which can cause serious respiratory problems. You’re more likely to have seen this in a bathroom or kitchen, but it can occur almost anywhere in the home, given the right conditions. You need specialist mould and condensation treatment.

If you’re experiencing condensation in your home, it’s important to address the root cause and invest in damp-proofing services to prevent further damage and ensure a healthy living environment. At Allerton Damp, we are specialists in the diagnosis of condensation and the measuring of internal air quality.

On this page, you’ll find useful information on condensation and mould treatment services, including information about mould on walls and its removal.

What Causes Condensation?

Condensation is an ever-increasing problem in today’s homes. Modern windows, doors and bricked-up fireplaces dramatically reduce the heat that is lost from our properties, which is a good thing in principle, but they also prevent air that has a high moisture content from escaping the home and being replaced by new air.

If you have condensation in your home, it is more than likely that a combination of high humidity and cold internal surfaces are causing the problem, rather than one or the other.  The common causes of condensation are:


Condensation is the formation of airborne water vapour on surfaces.  The amount of water vapour in any given air sample is indicated by its Relative Humidity (RH) value. As humidity increases, so does the likelihood of condensation. Air inside a property can increase in humidity as a result of a number of different factors, which can include:

Poor or no air extraction

An absence of suitable extractor fans in areas of high water vapour creation

Wet clothing

The drying of wet clothes or towels in property such as on radiators or clothes horses

Non-vented tumble dryer

The use of a tumble dryer that is not ventilated into the outside air

Dry hair

Drying hair in areas with inadequate ventilation

Moisture from cooking

The persistent boiling of pans of water without lids being on, or effective ventilation

Damp cellar/ floor

Evaporating water vapour rising from a damp cellar or through a damp solid or timber floor

Cold surfaces

Water vapour is more likely to condense if it collides with a colder surface, hence cold walls are susceptible to condensation. The common causes of walls becoming colder than desired are:

Insufficient heating

The absence of radiators or other sufficient heat source in a given area

Single-brick external walls

Walls without cavities retain less heat than those with them

Lack of sufficient insulation

Any wall or surface which does not have the benefit of some form of insulation

The recommended RH value for internal air is 40-50% and maintaining this has a positive effect on both the condition of our homes and our health.

How the dew point affects condensation

It is important to understand that RH is only one value which factors into whether condensation will form in the home. The dew point temperature of a surface and the temperature of the room it is in must be measured to understand at what point the surface will be affected by condensation. 

The dew point is the temperature that a surface must reach in order for condensation to form on it, given the state of the environment that the surface is in.

The dew point is never fixed and will increase or decrease depending on what the RH value of the air near the surface is. The table illustrates the relationship between RH, the room temperature and the dew point; the dew point temperatures can be seen in the grey section and are provided in Degrees Celsius.

What are the Consequences of Condensation?

Moisture, condensation, and the appearance of mould on walls often go hand in hand. Mould, especially black mould thrives on condensation. Living in a building that’s been affected by mould on walls can lead to respiratory issues like asthma, and a weakened immune system, making occupants more prone to illnesses. 

High humidity levels can also encourage the growth of wet and dry rot fungus in a home. If left unchecked, these fungi can damage the structure of a building, leaving any timber materials weak and vulnerable to collapse. It’s critical to act promptly to address any humidity and condensation issues to prevent further damage and ensure the safety of a home’s occupants.

The moisture created by condensation can cause serious structural issues in Yorkshire homes, in fact, prolonged exposure to moisture can lead to wet rot decay. Wet rot decay is a type of fungal growth that thrives in damp, poorly ventilated environments. It can cause structural damage to wooden surfaces, including beams, floors, and roofs, as well as reducing their strength and durability – making habitation highly dangerous.

Black mould thrives in the damp environments created by condensation. It can release spores into the air, which can trigger allergic reactions and respiratory problems in property occupiers. Black mould will often produce stains on walls and ceilings and produce a musty smell. To prevent the growth of black mould, it is important to address any condensation issues promptly, including improving ventilation, reducing humidity levels, and fixing any leaks or water damage.

Condensation & Mould Treatment for Walls

Tackling condensation is essential for improving the air quality in your home, and reducing the likelihood of mould growth. Reducing condensation levels requires a persistent and determined approach. 

Firstly, changes to your lifestyle might assist somewhat in reducing condensation, but it is likely that other technical interventions will be required to assist in the general reduction of the problem.  

As part of our full-service mould and condensation treatments, we can:

  • Install insulated plasterboard
  • Install industry-leading iFan mechanical extractor fans
  • Apply specialist insulating plaster
  • Install an industry-leading iPIV whole-house ventilation unit

Alongside our professional condensation and mould removal services, we also offer a range of specialist damp-proofing and timber preservation treatments.

Why air quality matters in your home

The quality of the air in our homes is currently a hot topic of discussion with a number of recent studies suggesting that controlling air quality in our homes can have many benefits for our health. 

Though the purpose of this page is to set out how condensation forms in our homes (in which air quality plays its part), we also illustrate here how safeguarding your home from condensation, if done correctly, can bring other benefits for your health.

Health benefits of good humidity

Air quality plays in important role in the health and well-being of a building’s occupants.  Properties with poor air quality can cause a range of health problems including asthma, allergies, headaches, dizziness, and fatigue. 

It can also create an uncomfortable living environment by producing unpleasant odours and high levels of humidity. Poor air quality can cause damage to the building’s structure and contents, such as peeling paint, warped furniture, and deteriorating fabrics. 

It is crucial to ensure good air quality by regularly ventilating the home, reducing sources of indoor pollutants and using humidity control techniques.

Maintaining the humidity of the air in your home at the correct level not only reduces the risk that condensation will form in your home, it has many other benefits too.  These benefits are set out in the table below, which you can use as a guide to compare how your home fares.



Why is condensation common in the kitchen?

A great deal of water vapour is created in our kitchens. Whether it’s the boiling of pans, running the tumble dryer or making a cup of tea, the kitchen takes the brunt of our daily creation of water vapour. That water vapour adds to the Relative Humidity of the internal atmosphere of the kitchen, which then settles on cool surfaces such as windows or wall as condensation.

Is leaving the heating on all day condensation treatment?

The use of heating to keep rooms warmer can assist in reducing condensation. However, aside from this being expensive and harmful to the environment, it doesn’t cure the causes of the problem. Condensation occurs as a result of humid air meeting cool surfaces; in heating a room, you keep the surfaces warmer and keep the water vapour in the air, rather than allowing it to form on the surfaces. A combination of good ventilation and insulation might prove a more economical solution.

I dry clothes on radiators, does that cause condensation?

The alternative is to dry clothes outdoors or use a tumble dryer of which there are two kinds; ventilated and condenser. A ventilated tumble dryer expels the humid air directly out of the property, whereas a condenser condenses the humid air into a reservoir inside the dryer. As some water vapour almost always escapes from a condenser dryer, it is normally preferable to use a vented model, but this necessitates an accessible vent being installed in an external wall. In any event, using a tumble dryer of any kind will normally be preferable to drying your clothes openly, either on radiators or clothes stands.

What’s an example of the condensation dew point in practice?

The following basic example should help you to understand how the dew point principle works in practice:

A four-walled room is kept at a constant temperature of 23°C by a central heating system. The room is used frequently and there is no ventilation in the room, which causes the RH of the air in the room to be 65% for extended periods of time. Two of the walls in the room are internal walls and their normal surface temperatures are each 21°C. Two of the walls are external walls; one was constructed as part of a recent renovation project and has the benefit of cavity wall insulation whereas the other is an older solid wall with no insulation.

It has been a cold month and the normal surface temperature of the insulated wall has been 18°C, but the normal temperature of the solid wall has been 15°C and the inhabitants have noticed that this wall appears damp in several places.

Identifying condensation is rarely a simple process as the traits of condensation can be remarkably similar to other problems such as rising damp and penetrating damp.

As such, we would always recommend that you contact our mould specialists if such a problem is discovered. Not only are we experts in diagnosing condensation, but we are also professional industry leaders in planning and installing measures which can reduce and resolve condensation problems in the home.

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