If you’ve just bought a new-build home, you probably expect it to be dry, warm, and low maintenance as soon as you move in. However, whether your house is days old or hundreds or years old, condensation and mould are ever-present threats that can occur at any time, no matter how modern your home is.
Condensation and mould don’t just look unpleasant. They can affect your health, cause damage to your property, and cost thousands of pounds to rectify. In this blog, we’ll cover the causes of condensation and mould in new-build homes, as well as some practical steps homeowners can use to take control and prevent these issues from taking hold.
Why is My New-Build Home Still Vulnerable to Condensation and Mould?
Even with the use of modern techniques and building materials, condensation and mould are ever-present in our living spaces, and so it is almost impossible to completely remove them from a building. Here are a few reasons why your new-build home is still vulnerable:
- Your home is still drying out: If construction on your new-build property finished shortly before you moved in, chances are that some areas are still drying out. Materials like plaster and concrete use a lot of water during construction, and it can take up to two years for moisture levels to balance out in your home.
- Modern building techniques: Newer homes take advantage of modern construction techniques and materials, and are often better insulated, sealed, and energy-efficient when compared to older housing stock. This is ideal to avoid heat loss, but the reduction in passive ventilation allows humidity to remain high within the property.
- Increased moisture generation: Regular activities like cooking, showering and washing clothes create a vast amount of moisture. New homes are designed with a standard level of moisture generation in mind. If you go above this level, like taking very long hot baths, or consistently drying clothes indoors, your risk of developing mould or condensation problems increases.
- Design or Installation issues: Use of unsuitable materials or designs can contribute to moisture retention, as can defects with plumbing or rainwater goods during their installation. Our blog on Common Problems in New Build Houses highlights some easily missed areas that might be contributing to humidity within your home.
If your home is built with more traditional materials such as timber, then it may have a different drying period than a modern brick or concrete construction. However, it is still at risk of condensation problems developing depending on how it is constructed and maintained, especially once you’re living in it.
What Causes Condensation and Mould?
There are several reasons for a build-up of condensation and mould in a property, including:
- Excess internal moisture: Moisture-creating activities like drying clothes, showering and cooking increase the amount of moisture within your home.
- Poor or insufficient ventilation: A lack of passive ventilation like trickle vents can allow moisture to build up if your home is sealed against losing heat. Not using mechanical ventilation like extractor fans can also allow moisture to accumulate. Furnishings placed against cold walls or blocking ventilation will also reduce airflow, and can inadvertently create ideal environmental conditions for mould to thrive in.
- Cold surfaces & poor insulation: Warm moist air will turn into condensation when it meets a cold surface and may create the perfect environment for mould to grow if the surface stays cold. Even an insulated building may still have colder areas that can allow moisture to settle.
- Construction moisture: If your building is drying too slowly, either due to low heating or a lack of ventilation, moisture may remain trapped within the building.
- Installation or maintenance defects: Plumbing leaks, poorly installed windows and doors, defective ventilation or poor external detailing can allow for moisture ingress or for humidity to remain within the building.
Check out our article, What Causes Condensation?, for more information on the root causes of condensation forming within a home.
What Signs of Condensation & Mould Should I Look Out For?
Condensation and mould have some telltale signs, including:
- Water droplets forming on windows or cold surfaces such as tiles.
- Damp wall patches with bubbling plaster and/or peeling paint or wallpaper
- Visible mould spots, especially around window frames or cold walls
- A musty or damp smell, especially in areas with inadequate ventilation or restricted airflow.
You can find more information on identifying an outbreak on our Black Mould Treatment page. If you can identify these warning signs early, it will be easier to fix before the condensation and mould can cause any extensive damage to your property.
What Can I do to Control and Prevent Condensation & Mould?
Your new-build home is in a drying period for the first two years of its life, so you should be patient when first understanding how moisture develops and how your behaviours impact the amount of moisture retained in your home. You should be especially vigilant with your moisture control methods during this time and adapt your home activities to ensure the building can dry properly.
There are a few things you can do at home to prevent condensation and mould from spreading further and causing damage:
- Reduce moisture generation: You should have a rough idea of how much moisture your home activities generate and make small lifestyle adjustments to reduce the amount of ambient moisture left after you’re finished. You should also be aware of introducing new moisture sources such as pets and plants, as this will increase the amount of moisture generated within your home. Drying clothes outside where possible, reducing time spent in the shower and using a cooker hood or opening windows while cooking are all great ways of reducing the amount of potential moisture kept within your home.
- Keep your home warm: During the cooler months, use the heating to maintain warmth in your home. A comfortable and energy-efficient temperature is usually between 18-21oC, but you might want to set your temperature slightly cooler in bedrooms to make it more comfortable while sleeping. You don’t need to have it on constantly: even setting it to come on automatically for half an hour on a morning and an evening can help keep the ambient temperature consistent for longer. This should reduce the number of cooler surfaces where moisture can condense.
- Keep your home ventilated: You should check your ventilation system and ensure everything is working correctly and isn’t obstructed. This includes trickle and window vents, extractor fans, and any other systems your home has. If your home has none of these, opening windows periodically can reduce the amount of humidity in your home (especially after moisture-generating activities like sleeping, showering and cooking). Check out our blog on Lüften to find out why opening your windows in the morning can make a huge difference to humidity levels within your home. You could also consider using a dehumidifier to remove moist air from a room. However, these should be properly maintained to ensure they’re effective at removing moisture from the air. Our blog Do Dehumidifiers Stop Mould? goes into the use of dehumidifiers in more detail.
- Monitor your environment: You can use a hygrometer to measure humidity within your home, either as a standard device that you can use when needed, or as part of a Smart Home set-up that can provide average measurements over time.
The average home should be around 50% humidity, but a new build home will often be around 60-65% humidity as the building materials need time to fully dry. If you spot any damp patches or mould spots, wipe down any surfaces carefully with a cloth, and use an appropriate cleaner on any mould spots. Black mould will reoccur if the root cause isn’t addressed, so you should look at your ventilation and heating methods if the problems recur. - Seek professional guidance: If you’ve tried all the above suggestions and you still have concerns with mould or condensation, then you should seek professional advice.
Your new build home will likely be under a guarantee, so you should contact the builder or agent to arrange a visit to assess any potential defects within the building or ventilation systems. If your home isn’t under any guarantee, our surveyors are available to assess any potential issues and advise accordingly: just request a survey to arrange a visit by one of our team.
What to do About Condensation in a New Build Home
New-build homes are more vulnerable to condensation and mould because of their long drying out period, occupancy behaviour, and their build specification to retain warmth in cooler climates.
When properly maintained with heating, ventilation, and a few changes in the way you generate moisture, you can keep your home dry and comfortable, as well as reduce the likelihood of mould or condensation causing problems down the line.
You should regularly check your ventilation systems as part of ongoing maintenance and ensure that if you are generating an increased amount of moisture that this is adequately removed from the home before it can condense on cooler surfaces. Even opening a window for 20 minutes in the morning or after a shower can have a massive impact on the amount of residual moisture that remains in the home.
You should also factor in additional sources of moisture such as pets or plants when identifying the amount of moisture you’re generating and adjust your behaviours to compensate for increased humidity within your home.
If you notice persistent condensation or mould problems despite maintenance, treatment and behavioural changes, you should seek professional advice, either from your builder if under guarantee, or our surveyor team if not. Your builder will be able to advise on how the installed ventilation systems should be used and can identify any defects with proper inspection.
If your home is not under a guarantee, our team are available year-round to assess and remedy any condensation or mould issue within your home.
With over 50 years of industry experience, our PCA-qualified surveyors are experts in assessing buildings from new-build to listed buildings and provide the ideal remediation solution to ensure condensation and mould are kept at bay no matter the materials used. You can also consult our Condensation Services page for more information on how Timberwise can remedy a damp or mould issue within your home.
FAQs:
Is condensation normal in a new build?
Yes, it is perfectly normal for condensation to be prevalent while your building is drying out. However, persistent condensation isn’t normal and may indicate concerns with your lifestyle or with the installed ventilation methods. If you’ve adjusted your moisture-generating activities and you’re using ventilation correctly and condensation is still present, then you should address this by consulting your builder or one of our experts.
Does good insulation mean no condensation risk?
Not necessarily. Correct use of insulation can help keep your surfaces warmer, reducing the risk of condensation forming. However, a lack of ideal ventilation will allow the moist air to remain trapped inside your home, and therefore will always present a risk of condensation or black mould problems developing.
If I see mould, is it always my fault?
Not always. It could be down to how your home is built: If your home isn’t designed with ventilation in mind, or the ventilation methods have defects, then these are not your fault. You should check your installed ventilation methods and any documentation provided to understand their ideal use and consult any guarantees of work if you suspect these are not working as intended.
How long until my house is fully dry?
Often it takes between 12-24 months for a home to achieve moisture balance, depending on occupancy, ventilation and moisture controls used in the property over this period.
Can I just buy a dehumidifier and forget about ventilation?
A dehumidifier can address the symptoms of high humidity within a home and are especially good in isolated areas without proper ventilation. They are also generally economical to run, even over long periods. A dehumidifier does require regular maintenance to ensure it works at ideal efficiency and effect: cleaning the filter is required every 2-4 weeks to ensure dirt doesn’t reduce functionality, and you’ll also need to empty the water reservoir as it fills to ensure it can remove as much moisture from the surroundings as possible. A home dehumidifier will also not have the strength required to deal with large-scale damp, and commercial dehumidifiers can be costly both to buy or rent and to run. Without addressing root causes such as ventilation or air flow, the issue may return.
