What Causes Condensation in my Loft?
When looking at condensation in loft spaces, it is important to concentrate on:
- What causes condensation in loft spaces? – as we always say on subjects like this, people often think first about how to remove condensation (we will come on to that!) but it is first important to understand the cause as, otherwise, you can remove the condensation only for it to come back. Nevertheless, we will explain later.
- What are the risks of condensation in loft spaces? – is condensation in loft spaces even something that you should be concerned about? Is it normal or something that can cause damage and risks to your property (spoiler – it can cause damage). We look at that below.
- How do you remove condensation in loft spaces? – once we have looked at the prior two points, we will then look at how to potentially remove the condensation.
As we explained in our guide to humidity problems, for condensation to occur the moisture in the air needs to reach what is called ‘dew point’, which is the point at which it changes from vapour (a bit like steam) into moisture droplets. You can work out dew point with our dew point calculator or even dew point chart which provided useful facts relevant to why condensation in lofts form.
For this to happen, you need relatively warm moist air coming into contact with a cold spot surface. In the same way as when you have a bath or a shower in winter and condensation collects on cold window surfaces. We have a guide on how to stop condensation on windows.
The same is happening in your loft or attic if you have condensation, especially on North-facing sides of your roof (which gets less sun). It can happen at any time, however, as you might expect it is more common in colder months when your outer roof surface will be cold. Although there are some things that can be done about that, the main question is answered next.
Where is the moisture coming from in my loft?
Clearly there can be a number of reasons why moisture can be in your loft. But here are some of the possible causes. Remember, as is common with some of these things, a combination of these factors can come together to make the situation more complex and problematic:
- As you might expect, one possible cause is a water leak in your loft. This can be cold water but, in some cases, can be hot water too. As you know, warm water gives off more steam etc into the air which increases the risk of condensation in the loft. However, any leaking water is a concern. Not least because it can result in a celling leak in the rooms below which brings other risks too.
- Quite often when people have condensation in lofts they spot it first after seeing damp patches on ceilings in their home upstairs. So if you spot that, take a careful look in your loft.
- In some instances, a leak in your roof can bring unwanted water into the loft space. However, this is perhaps a less common cause of condensation in loft spaces.
- A more common problem can be from extractor fans or extractor fan ducts bringing moisture laden / steamy air into loft spaces from bathrooms, ensuite or shower rooms. There are some situations whereby people vent extractor fans straight into loft spaces (don’t do that if you are considering it!) but more commonly there can be a split or break in the duct work meaning it is not venting outside.
- For more on this, read our article about condensation in bathrooms.
- Another cause could be that moisture (such as from bathrooms etc) is entering the loft space via gaps or cracks in the ceiling. This could even include a loft hatch which is not properly sealed which allows humid air to enter.
- A possible cause can also be water tanks leaks in loft (both hot and cold) which can contribute to higher levels of moisture in the air. That said, if they are fitted correctly and well maintained, they should not be a problem. Water tanks are one of the common sources of water leaks in houses.
- Many of the above can be made worse if you have high humidity or moisture in your house below, so although that might not be directly the cause, it can make it worse. In an ideal world you would be taking measures in your property to make sure it is not too humid and well ventilated.
- An additional contributing factor to condensation in loft spaces can be the structure of your roof, especially the membrane / underfelt you have. More modern underfelt is breathable, whereas older versions may not be. Plus, and we will discuss this more later, modern roofs often have tile vents to help with ventilation and fresh air circulation. On that particular point, if you have such vent tiles, make sure that they are not obstructed, for example by loft insulation etc. They work a bit like air bricks.
In many ways, much of the above has similarities to our guide to mould on walls. Which links also to…
What Damage can Condensation in Lofts Cause?
Before we actually discuss what damage can be caused. It is always important to remember that working in a loft space is a good example of why risk assessments are necessary. There are clearly issues around confined spaces, ventilation / air quality, potential tripping hazards etc – which can be made worse by excessive condensation and what that brings!
Now that is clear, here are some of the damage that condensation in loft spaces can cause:
- Mould problems – condensation in loft spaces often go hand in hand with mould problems. As we said below, they share certain characteristics and condensation can provide the moisture that mould needs to grow. As we said in our guide to what causes mould, things like poor ventilation, right temperatures, lack of sunlight and lack of disturbance can all contribute to mould forming.
- Structural problems – clearly, if you have a lot of condensation forming in your loft space, and it occurs for long enough, the moisture (measured with a moisture meter) can then get into other materials in your loft (directly or indirectly) and cause them do be damaged or even warped. This can include wood, plasterboard (for the ceilings below), loft insulation etc. This in turn can cause other issues such as damage to your ceilings or problems with damp etc.
- Damage to contents – people often use their loft spaces for storing personal possessions or things like Christmas Decorations, old photos, clothes etc. Getting moisture on these can cause damage to them too, especially over time and if the condensation drips onto them.
- Indirect damage – as we mentioned earlier, you need to take care in loft spaces and surfaces being slippery may cause someone to slip or fall, which can obviously cause damage, for example to the ceiling below.
- Damage to electrics – it is not unusual to have wiring in loft spaces for lights, extractor fans etc in ceilings below for example, or even for lights in the loft. As you will likely know, moisture / water and electrics are not a good combination and, in extreme circumstances, can even cause sparks and fires.
How do I Stop Condensation in my Loft?
In many ways, stopping condensation can come down to resolving the original cause of the condensation in loft spaces, as listed earlier. However, that said, here are things to consider:
- Make sure no moisture or steam is entering your loft, especially from bathrooms, showers or laundry rooms below. Try to control the moisture in your home in general.
- Make sure your loft is well ventilated, using some of the methods mentioned earlier.
- Make sure you keep your water tank regularly checked and maintained by a professional. People often spot things in lofts late because they do not go up there.
- This may not be easy to resolve but, more modern breathable roofing membranes under roof tiles do not allow liquid water to penetrate from the outside but they do allow water vapour to escape from the inside. Older materials like bitumen are not breathable like newer materials.
- If you think you have a water leak, make sure you get a professional leak detection specialist such as us to find and fix your water leak! On that, if you spot any signs of damp or sagging in the ceiling in your loft, do not ignore it and get help too.
- We offer condensation surveys to help understand the cause of excessive condensation and make recommendations to resolve it too, tailored to your specific property too.
We have a separate guide to condensation on pipes which can happen in lofts too.
How to Dry Out Condensation in Loft?
What work is involved in drying out your loft from excessive condensation and associated damp and moisture will depend on the extent of the damage and how long the problem has been happening in there. Plus, the specific design, layout and construction of that loft is very relevant.
We are experts in water damage restoration, including condensation damage, and will be happy to help you dry your loft space. This will possibly involve the use of air movers, heaters (depending on the time of the year) and refrigerant and desiccant dehumidifiers to remove the moisture and return your loft space back to normal.
So if you have condensation in loft spaces in your house, get in touch with us today.
On the subject of air movers, we mention them in our articles about if fans are effective at cooling when it is hot in summer or during a heatwave.
Is normal to get condensation in your loft?
Generally, you should not get much condensation in lofts. Loft spaces are usually well ventilated which helps to stop condensation building up. If you have particularly bad condensation in your loft / attic space then you make have a problem, remembering that condensation can lead to damp and mould. The important thing to understand is where the moisture is coming from that is causing the condensation in lofts.
Will a dehumidifier stop condensation in my loft?
Although a dehumidifier will help to control condensation in lofts, it is generally not the best long-term solution. Especially as (a) they are likely to be expensive, (b) need installing and (c) relatively expensive to run regularly. If you have condensation in loft spaces, there is likely an underling cause of that and we can help investigate it for you. Stopping the cause will likely stop condensation in lofts.