What are the main types of damp? Plus the best ways to fix them

There are several types of damp that affect properties in the UK. Each one can cause different problems around your home and they all have different symptoms (although some are similar). Due to the varying kinds of damp the solution for each can vary.

In this article we will be looking at each different type of damp and some of the most common causes.

Following this, we will look at a variety of solutions to each damp issue. This will cover DIY solutions, as well as cases where you may need to hire a professional.

What are the main types of damp?

There are three main types of damp that occur in UK homes. These are:

• Condensation damp
• Penetrating damp
• Rising damp

Of the three, condensation is the most common, this is followed by penetrating damp and then rising damp.

According to a government housing survey, based on physical surveys carried out in UK homes, around 4% of homes suffered with damp. This rose to 7% in the private rented sector, and 6% in social rented homes.

However, in the same government survey, when homeowners throughout the UK were surveyed, around 7 million households claimed their home suffered with problems from damp, condensation, or mould. This represents roughly 30% of UK properties.

As you can see, based on these numbers damp is quite common.

What is condensation?    

As we have already mentioned condensation is the most common cause of damp and mould. It is different from other types of damp, mainly because it is generated inside the property. In contrast penetrating and rising damp are entering the property from outside.

Condensation is caused by moisture created in the home. This can come from a variety of activities including:

• Baths and showers
• Cooking
• Drying clothes
• Boiling the kettle
• Breathing
• Sweating

As you can see all these activities are creating moisture or steam. All result in the increase of water vapour inside your property.

When this is combined with poor ventilation and airflow throughout your home, condensation is inevitable.

In general properties with good ventilation and higher EPC ratings (energy efficiency) tend to suffer less with condensation this is because they have a balanced temperature and good ventilation. This ensures that moisture in the air is removed and fresh air is regularly circulating into the house.

Temperature can have a large impact on condensation. Water vapour collects in warm air and is attracted to cold surfaces.

These cold surfaces are referred to as a dew point and when the warm air meets them, the moisture condenses on its surface and turns back to liquid water.

Condensation in old vs modern properties

In older properties with solid walls or cavities without insulation, it is quite common for external walls to be significantly colder than internal walls.

A good example of this is a Victorian mid terrace.

In this type of property, the front and back wall is unlikely to be insulated. As a result, it will usually be colder than other surfaces. This provides a perfect dew point for moist air to condense on.

On the other hand, in a more modern property that is well insulated the walls should have a balanced even temperature.

However, even modern properties with good insulation can suffer with condensation. If they are not well ventilated and moist air isn’t removed, you will find condensation is attracted to other cold surfaces, such as windows.

Ideally the best scenario is a good combination of insulation and ventilation to avoid condensation in your home.  

How to reduce condensation

Getting rid of condensation entirely will be quite difficult to achieve. After all, we all need to breath and household chores will always create steam and extra moisture in the air.

However, we can take steps to reduce it. Below are some of the best ways to reduce condensation:

• Regularly open windows – This is completely free and is a great way to circulate new fresh air into your home.
• Open doors around the house – This can be particularly helpful in rooms that are used less where fresh air doesn’t get much chance to circulate.
• Extractor fans in kitchen and bathroom – Based on the government survey we mentioned previously homes with fans installed were 40% less likely to have issues with damp.
• Use a dehumidifier – This is a low cost and effective way of extracting moisture from the air in your home. You can read more about how dehumidifiers get rid of damp by clicking here
• Insulate cold external walls – This can be done in several ways. One of the easiest is applying insulated plasterboards. You can read more about how insulated plasterboards can stop condensation here

The main goals you should strive for when trying to stop condensation are reducing moisture in the air and improving energy efficiency by maintaining a more balanced temperature.

What is penetrating damp?

Penetrating damp is any form of damp that penetrates your property from outside. This will usually be as the result of an external defect; this includes things like:

• Damage to the roof and chimney
• Cracked or damaged bricks
• Old, damaged pointing
• Cracks and holes in render and pebbledash
• Damage or blockages to guttering and downpipes
• Holes where wires and other services enter the home
• Old or poorly applied sealant around windows and doors
• Bridging above the DPC due to higher outside ground level

All of these have the potential to cause penetrating damp. Some will be easier to identify than others, and some will need the help of an expert, to locate the exact problem.

It is also quite common for penetrating damp to be confused with internal leaks. This is usually a result of plumbing issues, such as leaking pipes, sinks and radiators.

Penetrating damp will usually get worse over time, plus, it is almost always worse in winter months, where the weather is wetter, and more water is able to penetrate inside your home.

How to fix penetrating damp

Penetrating damp is a broad topic. There are many ways that damp can penetrate your home from outside.

Because there are so many potential causes, there are also many ways it can be repaired. This could vary from small jobs, such as replacing silicone sealant around windows, or a small bit of pointing. All the way up to big jobs, like re-rendering your entire house, or installing a new roof

There will be many jobs that you can do yourself, and there will be many that will need the help of a professional trade’s person.

The first thing you will need to do is perform a visual inspection. If you are able to locate the problem, you will then be able to decide if this is a DIY job or one for an expert.

You can read a much more detailed article about how to fix penetrating damp here

What is rising damp?

As the name suggests rising damp if moisture rising from the ground below your property. This is the least common type of damp and is also the type that is most often misdiagnosed.

To the untrained eye, it is easy to mistake penetrating damp and even some condensation for rising damp. Therefore, if it is not obvious, a damp proofing expert may be required to offer a correct diagnosis.

Rising damp occurs when moisture rises from the ground. This is more prevalent in winter when the water table is higher.

Water enters the walls below ground level and wicks up through the pours and capillaries in the bricks and mortar. In most properties built after the 1870’s a damp proof course should have been installed to stop water rising any higher.

If you are suffering with rising damp, then it is likely your DPC has failed. Alternatively, if your property was build pre-1870’s there is a good change a DPC does not exist.

If you do have rising damp, it will need fixing. Just like penetrating damp, if rising damp is left untreated the problem will get worse.

This can result in a lot of damage to your internal decorations, carpets, and woodwork. In more serious cases it could even result in structural damage if the problem is bad enough and left untreated for a long period of time.

How to fix Rising damp

There are several ways that rising damp can be repaired. These include:

• Replacing the original DPC
• Injecting a chemical DPC
• Using damp proofing rods (similar to DPC injection)
• Electro osmotic system

DPC injection and rods can both be performed DIY. The application of each is relatively simple. You will need to drill holes at regular intervals in the mortar at DPC level (roughly 150mm above external ground level). Once the holes are drilled you can insert the cream or the rods until they fill the holes.

Once inserted both systems release a waterproof sealant that seeps through the pours in the mortar and surrounding masonry. This creates a waterproof barrier that will stop any future rising damp.

If you decide to replace the original DPC this is a much more technical job. It involves structural work, where bricks need removing from the wall. This may require temporary supports and due to this it should not be attempted as a DIY project.

Electro osmotic systems are the least common form of treating rising damp. They are also more complicated and should not be attempted DIY.

The system uses an electrical charge, which is achieved by tapping into your main electric supply. Therefore, it is a job that will require professional expertise.

To read a much more detailed article about how to fix rising damp click here

What if you’re not sure?

Identifying damp is not always a straightforward process. In some cases, the cause can be obvious, in others it won’t be as clear.

Even when you do identify the problem, there is a chance you won’t be able to carry out the work yourself.

Obviously if you are a keen DIY enthusiast, there are many jobs you could tackle yourself. At the same time even a DIY’er will have their limits. Then there are those who simply don’t do DIY at all.

If you are at a point where you either:

• Don’t know here to start
• Think the job is too big
• Or simply don’t want to do the work yourself

Then it would be advisable to talk with a local damp proofing expert.

Ideally, to make sure you hire the best company, at the best price, you shou try to get multiple opinions and quotes.

One easy way of doing this is by using local trade comparison sites. One of the best for local damp proofing companies is a service called Bark. When using a company like this, there are 3 major advantages:

1.  Companies are verified by the service
2. You can view their company profile with all relevant qualifications
3. Previous customers write reviews so you can read past customer experiences with each company.
4. Most importantly, the prices tend to be significantly lower. Each company is competing for the same job, so prices tend to be extremely competitive.

Whats more, many companies offer a free initial inspection and quote. This means you can have multiple eyes on the job, as well as individual quotes to choose from.

To get up to 5 local damp proofing quotes click here

Conclusion

As you can see there are 3 main types of damp. However, each one is quite different and for issues involving penetrating damp, there is a whole host of potential causes.

You should always try to identify the problem yourself, but it is not always clear cut, so don’t hesitate to ask a professional’s opinion.

In many cases, the job to repair damp can be small. This will mean, it’s either low cost to hire a professional, or it’s something you can do yourself.

The most important thing is you need to make sure you resolve the issue sooner rather than later. When any type of damp is left untreated, it will usually get worse over time. The result will be more cost, and more disruption the longer it is left.