Moisture in exterior walls is a common problem that not only affects the appearance of your home but can also cause structural damage. It can lead to mould growth, loose façade stones and unhealthy indoor air quality. Fortunately, there are effective solutions to combat and prevent moisture in exterior walls. Aquaplan tells you all about the causes and consequences of moisture problems and the best methods to tackle them.

Moisture problems in exterior walls can arise from various factors. The causes we most frequently hear from our customers are:

• Penetrating damp: Driving rain penetrates porous bricks or damaged mortar. Southwest-facing walls often experience heavy rain and wind, making it easier for moisture to seep in. This problem is common in older homes where the façade cladding is worn out or offers insufficient protection.
• Rising damp: Moisture from the ground rises into the wall, especially in older homes without damp-proof courses or with poorly functioning DPCs. This type of moisture problem can cause long-term damage and is often visible through peeling plaster and a musty smell indoors.
• Leaks: Issues with gutters, downpipes, or a poor drainage system can cause water to flow directly onto the façade. This can be particularly problematic in winter months when freezing and thawing alternate, exacerbating cracks in the façade.
• Roof overhang: When the roof edge does not extend far enough, the façade is not protected against driving rain. As a result, bricks and mortar are more quickly affected, leading to penetrating damp.

Environmental factors, such as high humidity and insufficient ventilation, can also contribute to the development of moisture problems. 

Customers frequently report visual signs that may indicate moisture problems. Think of moisture stains and dark rings on the wall, white deposits, or moss and algae growth at the bottom of the walls. But moisture problems are not just an aesthetic concern, they can also damage your home. Some common consequences include:

• Damage to the exterior wall: Moss and algae growth, white salt deposits, cracks in the façade and loose mortar.
• Indoor problems: Loose skirting boards, peeling wallpaper and mould formation can occur if moisture penetrates indoors.
• Structural damage: Prolonged exposure to moisture can compromise the stability of walls and lead to serious structural issues. This can result in costly renovations or even dangerous situations.
• Energy costs: Damp walls lose their insulating properties, causing heating costs to rise. This makes maintaining a comfortable indoor climate harder, especially during the winter months.
• Health risks: Moisture problems can promote the growth of mould and bacteria, which can lead to allergies and respiratory issues.

Not all exterior walls are equally prone to moisture problems. The degree of susceptibility often depends on the material. This is something our experts always look at closely.

• Brick: Highly porous and quickly absorbs moisture. The degree of moisture absorption depends on the quality of the brick and the finish of the mortar.
• Concrete: Less porous, but cracks can cause moisture problems. When water penetrates cracks and freezes, it can further crack and deteriorate the concrete.
• Plaster: Blocks moisture, but if there is already moisture in the wall, it is difficult for it to dry out. A moisture problem behind plaster is often harder to detect and can go unnoticed until serious damage occurs.

Different types of moisture problems require a specific approach. Before starting any treatment, it is essential to identify the cause. Penetrating damp usually occurs in areas above 1 metre in height, while rising damp is typically found at the bottom of the wall. Ensure you use the right product for the specific situation.

Penetrating damp is caused by driving rain that penetrates the façade. This problem can be effectively addressed with:

• Rain Protect Liquid: A liquid impregnation agent that penetrates deep into the brick and forms an invisible water-repellent layer. You apply it in multiple layers to prevent further damage. It also protects the façade against future penetrating damp. Want to see this product in action? Product expert Kevin shows you how to use it in this video tutorial! 
• Rain Protect Hydrofuge Cream: It is applied with a brush and gradually soaks into the wall. The cream is no longer visible after application. One layer is ideal for maintaining the natural look of your façade while providing a protective layer against moisture. Want to apply Rain Protect Hydrofuge Cream correctly? Here’s how! 
• Rain Protect White: An elastic, white wall coating that is moisture-resistant and covers irregularities in the wall. This product is particularly suitable for rough surfaces and provides durable protection against moisture.

Rain Protect Extreme: This coating forms a waterproof layer that blocks moisture from penetrating your walls, thus protecting them from moisture infiltration.

For rising damp, it is important to create a moisture barrier to prevent groundwater from rising into the wall. This can be done with:

• Wall Protect Inject Liquid Kit: With this kit, you drill holes in the wall and inject a moisture-resistant agent that forms a permanent barrier. It is an ideal solution for homes with structural moisture problems and provides long-term protection. It can only be used on solid-brick interior and exterior walls.
• Wall Protect Inject Cream Kit: The injection gel provides a barrier against moisture. This extra protective layer blocks and prevents further moisture problems, ensuring long-term protection of the structure. It can be used on solid bricks, high-speed building bricks, breeze blocks, concrete blocks, sand-lime bricks, cellular concrete and natural stone.

Moisture problems can also be caused by defective gutters, downpipes, or a roof overhang that is too short. In this case, it is important to:

• Inspect and repair gutters and downpipes: Ensure that rainwater drains away correctly and does not splash against the façade.
• Provide extra roof protection

By addressing these issues promptly, you can extend the lifespan of your façade and prevent future moisture problems.

Kevin, our product expert, always advises following these steps for the best results. Here’s how we do it:

1. Clean the wall: Remove dirt, algae and loose mortar before starting any treatment.
2. Repair any damage: Ensure that mortar and cracks are fully repaired.
3. Apply the right product: Choose the appropriate treatment for the moisture problem.
4. Allow the product to dry and penetrate: Give it sufficient time to properly penetrate the wall.

Everything you need to know to tackle a damp façade can be found in our step-by-step guide!

Correct treatment can remain effective for 5 to 15 years, depending on weather conditions and proper application. You can easily check if the treatment is still working by seeing if water still beads off the wall. If not, it’s time for a new layer.

It is also important to clean your façade periodically and repair cracks promptly. Using a soft brush, garden hose and an environmentally-friendly cleaning agent like Garden Clean Bio Based or Garden Clean Scrub Free helps remove dirt and moss without damaging the façade. Want to paint the wall after treatment? Use a water-based wall paint for the best results. A well-maintained façade not only ensures a beautiful appearance but also significantly extends the lifespan of your home.