Key Takeaways
- Water ingress through brickwork often stems from poor detailing, lack of drainage, or cracks and gaps in the brick/mortar system.
- Effective prevention focuses on ensuring correct wall construction (cavities, flashing, drainage), good maintenance (repointing, sealing) and diverting external water away from the structure.
- Simply applying a sealant or repellent is not enough—moisture management means dealing with the cause (e.g., leaking gutters, bridging soil level, cracked pointing) rather than just the symptom.
- Early detection of water penetration signs (efflorescence, damp patches, spalling bricks) allows more cost-effective remediation and prevents more serious damage to structure and finishes.
- Regular inspection and maintenance of external brickwork (clean gutters, check joints, ensure air-bricks and cavities are clear) are key to long-term prevention of water ingress.
Moisture issues have become a modern-day concern in the UK. According to recent reports, 2 million households have moisture issues facing them and the main cause is water ingress.
This problem is common in the country because of the specific environmental conditions and the fact that most of the buildings here are old.
If not properly checked, water ingress creates a way for subsequent issues like mould growth, structural damage, and costly repairs.
Fortunately, it is a problem that you can completely solve and stay safe. This article takes you through the steps to identify, solve, and prevent water ingress now and in the future.
Common Causes of Water Ingress
Before you can think about stopping water ingress, you need to first of all understand how it occurs. Knowing the source of the problems will give you a starting point when attempting to get the best solutions.
Damaged/missing mortar joints
The mortar serves as a “glue” that holds bricks together. However, it wears down after a prolonged duration of exposure to the elements. The result is gaps that can allow water to get into a building.
Missing/Damaged DPC
The role of DPC is to stop rising damp coming from the underground. When this barrier is missing or damaged, moisture from the ground will easily find its way into the building.
Cracked or spalled bricks
Some water trapped within the bricks can expand when frozen. This expansion can cause or worsen them creating a way for water to enter into the building.
Blocked or broken gutters and downpipes
If rainwater is not well channeled, it can trickle down the sides of the building increasing the risk of damp penetration.
Defective or missing cavity wall insulation: Poor insulation can trap moisture within walls, worsening internal dampness rather than preventing it.
Why is Water Ingress a Problem?
- Damp & Mold Growth – Wet walls and ceilings encourage mold, which can be harmful to health.
- Damage to Paint & Plaster – Water makes the paint bubble and peel off.
- Weakens the Structure – Over time, too much water can weaken walls and floors.
- Bad Smell & Unhealthy Air – Damp areas create a musty smell and poor indoor air quality.
Dealing With Water Ingress
Now that you know what causes water ingress, the next important thing you must know is how you can identify this problem in your property.
Signs of Water Ingress
Internal Indicators:
- Damp patches on walls and ceilings that get worse when it rains.
- Peeling paint and wallpaper.
- Bad odour and mould growth near skirting boards and in corners.
- Cold, clammy walls due to moisture.
External Indicators:
- White salt deposits (efflorescence) on the walls.
- Cracking or missing mortar.
- Green algae or moss growth on bricks.
- Damp patches that won’t disappear even in dry weather.
How to Identify the Source
- Visual examination of the bricks, gutters, and roof edges can reveal pooling water.
- Using a handheld moisture meter to measure moisture content in walls.
- Watch during rain to see how water moves around the structure noting where it overflows or accumulates.
- Involving the expertise of a damp surveyor can help identify even the most hidden issues.
Solutions to Stop Water Ingress
Once the cause of water ingress is identified, repairs and preventative measures should be implemented to stop further damage.
Repairing Brickwork and Mortar
Mortar and brickwork constitute the protective outer layer of a building. When these materials get worn over time, walls become permeable which allows water seepage. Restoration guarantees a strong and weather-resistant exterior.
Repointing Mortar Joints
- The first step is removing the old crumbling mortar. You should remove it to a depth of at least 15mm.
- Next is to apply fresh mortar. In the case of older buildings, experts recommend using a new lime- based mortar as it maintains breathability while resisting water ingress.
Sealing Small Cracks
- Fine cracks can be sealed using a breathable masonry filler, preventing moisture ingress while allowing trapped water vapour to escape.
Improving Water Drainage
Poor drainage allows water to accumulate around your property increasing the chances of water ingress through the brickwork. To avoid this, improve drainage as follows:
Clearing Gutters and Downpipes
- Check the gutters and downpipes to ensure there are no blockages that could cause water to spill onto the walls.
- Consider installing gutter guards to reduce maintenance needs.
Installing or Repairing Flashings and Coping Stones:
- Damaged lead flashings around roofs, chimneys, and parapets must be replaced to stop leaks.
- Secure coping stones on parapet walls to prevent water pooling.
Applying Waterproofing Treatments
Water-repellent treatments can enhance brickwork’s resistance to moisture while allowing it to breathe.
Using a Breathable Masonry Cream
- Unlike conventional waterproof paints, breathable treatments penetrate bricks, repelling water while maintaining vapour permeability.
- Apply according to manufacturer instructions for maximum effectiveness.
Avoiding Non-Breathable Coatings
- Non-breathable paints and sealants trap moisture inside walls, exacerbating damp problems rather than preventing them.
Addressing Internal Damp Issues
Even with external repairs, internal damp issues should be managed to prevent reoccurrence.
Installing a Damp-Proof Course (DPC)
Chemical injections or physical barriers prevent rising damp from affecting internal walls.
Improving Ventilation
- Use extractor fans, install air bricks, or employ dehumidifiers to reduce condensation and moisture build-up inside the home.
Preventative Maintenance Tips
Regular maintenance can help to stop water ingress from becoming a recurring issue.
- Check your brickwork and mortar once a year and deal with any damage as soon as you notice it.
- Ensure all gutters and downpipes have no blockages to allow for effective water flow.
- Inspect the roof flashing and pointing especially after heavy downpours.
- Apply a breathable water-repellent coating to the brickwork occasionally for extra protection.
- Improve ventilation to avoid condensation that leads to damp issues.
Conclusion
Water ingress can be a threat to your health and your property structure. It can cause dampness that would eventually destroy your property foundation leading to costly repairs or in the worst case bring the entire building down.
As per your health, the same problem offers the most ideal condition for mould to grow and as you might be aware, mould causes health issues like asthma, skin irritations, and allergic reactions.
Don’t wait until damage occurs—take action now to protect your home and health.
Frequently Asked Questions
What are the common causes of water ingress through brickwork?
Water can penetrate through defects such as cracks in bricks or mortar joints, bridging of the damp‐proof course, missing or blocked cavity drainage, insufficient flashing around openings, or external drainage failing to divert rain water away from the wall.
How can I tell if water is getting in through my brick wall?
Look for white salt deposits (efflorescence) on the surface, damp patches inside rooms adjacent to the wall, spalling or flaking of bricks, moss or algae growth on the brick face, or mortar joints that are deteriorating or missing.
Can I just apply a masonry water repellent to stop the problem?
A repellent may reduce surface absorption but on its own it won’t fix the underlying issue. The construction detailing (flashing, cavity, drainage), external water flow, and integrity of the wall must be addressed too. A coating without fixing those will often fail.
What maintenance should I do to reduce risk of water ingress?
Ensure gutters and downpipes are clear and divert water away from the building, keep soil levels below the damp-proof course, inspect mortar joints and repoint where needed, check that cavity or wall drainage is functioning, and apply corrective measures if the brickwork shows damage.
When should I call a professional for brickwork water ingress issues?
If you’re seeing repeated damp penetration despite attempts to manage it, there’s structural damage (cracks, bulging walls), or you suspect the wall construction (cavity, DPC, flashing) is compromised then engaging a qualified surveyor or damp specialist is advisable.
