Go back
Spray Foam Insulation

Top 8 Causes of Damp on Internal Walls

top 8 causes of damp on internal walls

The average UK home has to deal with a huge amount of rain during the year. With that in mind, it’s hardly surprising that homes suffer from damp and mould.

Damp and mould can appear on the internal walls, and the causes of damp on internal walls are always different.

From a broken or breached damp proof course, to incredibly ineffective drains, the reasons are endless. That being said, let’s take a look at the causes, but also at solutions for solving damp on internal walls once and for all

Old or New House?

Before we explore the causes of damp on internal walls, it is important to understand that not all homes are created equal. In this respect, old and new buildings tend to differ:

– Old buildings are designed in such a way that they must be allowed to breathe

– New buildings work on a system of defensive barriers that keep moisture out

Now, remember, installing insulation is usually the fix for condensation, damp, and mould. However, when you install it in an old building, there are a few things you must pay attention to. One is that you have to keep a vapour control layer for condensation.

If you seal the old building, it will be warm in the Winter, but it will also cause the house “to sweat”. The result is condensation, and damp on internal walls.

Types of Damp

There are also two types of damp that should be eliminated before we talk about solutions to damp on internal walls. Those two types are: rising damp, and penetrating damp.

If the damp patches rise from ground level, or there is a powdery deposit on wall surfaces, the cause is rising damp. This damp occurs when there is a failure or absence of a damp-proof course.

If you live in a flat above ground level, you won’t have to deal with rising damp. The best way to solve rising damp problem is to improve the drainage of the site where your property is situated.

In this instance, you must make sure that the ground surrounding the building is sloping away from your property.

Penetrating damp is the next problem, and happens when water penetrates from outside, deep into the brickwork, through cracks or gaps in the outside walls.

Regular maintenance of your external walls, as well as wall insulation can prevent damp from penetrating inside the home.

That being said, let’s take a look at the most common cause of damp on internal walls...

top 8 causes of damp on internal walls Plumbing is an important aspect of the quality of your home. Any tiny drips can cause large and even intense damp patches. Now, you might think that the escape of water might be small

Damp Proof Course Not Present or Broken

In most cases, this is the cause for damp. Check where damp is appearing. Is the damp appearing on the walls just above the skirting boards? Rising damp doesn’t get above 1.2 as gravity takes over. That means you should check whether your damp proof course is faulty or bridged.

What is the damp proof course? This is a waterproof layer that prevents water and moisture from travelling up your wall. Usually, the DPC is inserted as a vertical course, where the external wall meets the internal. This way, water is prevented from travelling.

Older buildings usually do not have a damp proof course installed.

Plumbing

Plumbing is an important aspect of the quality of your home. Any tiny drips can cause large and even intense damp patches. Now, you might think that the escape of water might be small.

However, if it is regular and concentrated on the same spot, it can result in intense damp patches, that are hard to fix.

The overload of damp can even spill into your neighbours area, which is even more troubling.

If you suspect that the problem’s with your plumbing, you need to check your water pipes, as they might be corroded. Also check whether there are failing waste pipes in the old bathroom, or any damaged seals around the showers and baths.

top 8 causes of damp on internal walls One of the most common causes of damp on internal walls is condensation. What happens is that condensation forms when warm moist air within a room touches a cold internal wall or surface. The warm, moist air cools down, and condenses back into water. The condensation will sit on the internal wall, and create damp patches all over it

And There’s More!…

Leaking Gutters

We mentioned at the beginning that one of the causes of damp on internal walls is guttering. When gutters leak, there are two ways water can go. The first one is run directly down the outside of the wall for a short distance.

The other option is splatter on the ground and window cills below. Guttering and leaks in the gutter result water directly into the roof space. Check if there are any tracks of water in the roof, and splattering from gutters splashing water onto walls.

Undersized Gutters

Another problem with gutters is undersized gutters. This usually happens with older homes. When the home was first built, the gutters were suitable for the rainfall. However, climate change has contributed to more frequent and rainfall.

That means that the gutters are too small now to cope with the changes. Your only option is to replace them. Check for water spilling over the edge of the gutters. If that happens on regular basis, you’ve got a problem.

Downpipes

If you have old cast-iron downpipes, you might get damp without being aware. Downpipes that contain sharp bends are also prone to blockage from debris washed in from the gutters.

Check if there are any holes in the back of the downpipes, and whether there is water tracking from the downpipe along brackets.

causes of damp on internal walls

You need to be careful when you replace solid floors. Excess moisture from below the floors passes up and harmlessly into the air. However, when floors are replaced with modern design that prevents this from happening, moisture has to travel under the floor and into the adjoining walls

Cement Rendering

Usually, this type of coating is used on the exterior of walls. However, the problem with cement coating is that it can develop cracks over the surface. The size will depend on the quality of the render and how skilled your contractor was.

However, the cracks will happen, and they are impossible to prevent with cement rendering. These cracks will allow water into the wall, and since it cannot escape, the result is troubling. Condensation from inside of the house can no longer escape, and the result is damp on the inside of the walls.

Replacement of Solid Floors

You need to be careful when you replace solid floors. Excess moisture from below the floors passes up and harmlessly into the air. However, when floors are replaced with modern design that prevents this from happening, moisture has to travel under the floor and into the adjoining walls.

The result is more moisture accumulates in the base of the walls and makes them damp.

Cold Spots Resulting in Condensation

One of the most common causes of damp on internal walls is condensation. What happens is that condensation forms when warm moist air within a room touches a cold internal wall or surface. The warm moist air coos down, and condenses back into water. The condensation will sit on the internal wall, and create damp patches all over it.

You need to identify the problem that is causing the cold spots. Some of the problems are cracks in the mortar. Are there are any air leakages in your home? Is the condensation appearing on the chimney breast? The cause might be poorly ventilated chimney breast.

top 8 causes of of damp on internal walls Wall insulation allows the home to breathe, and is permeable to water vapor. In the same time, the insulation allows air and moisture to pass from one side to another

Solutions For Damp on Internal Walls

Now that we know most of the causes of damp on internal walls, let’s take a look at some solutions. Nobody wants to live in a home with damp. After all, damp can damage your internal walls. What can you do?

The solution for damp is insulation. It’s that simple. But what type of insulation? Let’s explore the two main options in a little more detail:

Wall Insulation

Wall insulation is your first option. This professional product is designed to insulate bricks and porous building materials. On application, it bonds with the surface immediately, and then penetrates up to 17 mm into the brickwork, creating an invisible insulation barrier.

Based on nanotechnology, wall insulation protects your home against rain, algae, pollution, oil, and much more. You can apply on both concrete and bricks. Once installed, the insulation reduces water absorption by more than 95%.

Wall insulation allows the home to breathe, and is permeable to water vapor. In the same time, the insulation allows air and moisture to pass from one side to another.

This improves the thermal conductivity of your home, resulting in lower thermal resistance by up to 50%.

That being said, tests have shown that you definitely want wall insulation. Damp content of just 5% in a plain brick wall will lower your home’s insulation performance by 50%. The thermal conductivity of your wall decreases vastly with dampness.

top 8 causes of damp on internal walls

Spray foam is a 100% water blown material, and expands quickly up to 100 times its original volume and size. This allows the foam to fill all the cavities in your wall, and provide an unrivalled R-value, like no other insulation material on the market

Spray Foam Insulation

While wall insulation is applied on the exterior of the walls, spray foam insulation is applied on the internal spaces and cavities.  

One of the most efficient insulators available, spray foam provides an air-tight seal to your home, transforming it into a thermal envelope. That means that heat stays inside during Winter, whilst also ensuring that it remains cool and comfortable in Summer.

In addition to this, spray foam insulation is also designed to control airborne moisture, providing the perfect remedy to damp and mould.

Installing spray foam insulation will reduce energy bills by up to 30%. And the best part is, spray foam does not sag, shrink, or experience any other form of degradation over time.

Spray foam is a 100% water blown material, and expands quickly up to 100 times its original volume and size. This allows the foam to fill all the cavities in your wall, and provide an unrivalled R-value, like no other insulation material on the market.

And because it is versatile, you can use it for even the hardest to reach areas in your home.

Ready to take the next step? Request your free site survey today by calling 0800 1700 636, or by simply clicking the button below!