Rising Damp on External Walls: How to Spot It, Stop It, and Protect Your Home
Rising damp is one of the most persistent and damaging issues homeowners face. While many people focus on damp appearing inside the home, damp on external walls can be just as serious — and often harder to detect until it begins affecting interior spaces.
At Henderson Wood, we’re dedicated to helping homeowners understand the risks of rising damp and how to tackle it effectively. Here’s everything you need to know about rising damp on external walls, from the warning signs to proven solutions.
What Is Rising Damp on External Walls?
Rising damp occurs when moisture from the ground moves upward through porous building materials like brick and mortar by capillary action. External walls often show the first visible signs of this moisture movement.
If ignored, rising damp on external walls doesn’t just remain an exterior issue. Over time, the moisture travels inward, causing serious damage to interior walls, floors, and even ceilings. This can lead to structural weakening, rot, costly repairs, and potentially hazardous mould growth that affects your family’s health.
Signs of Rising Damp on External Walls
Catching rising damp early can save you thousands in repair costs. Here are some of the most common signs to look out for:
Tide marks or damp staining on external brickwork
Discolouration or dark patches on walls
Efflorescence, a white powdery deposit left by evaporating salts
Moss or algae growth on brickwork, especially near the base
Crumbling mortar joints and spalling bricks
External walls that feel damp or cold to the touch
Musty smells around the outside of your property
If left untreated, you may also notice signs developing inside your home, including:
Peeling plaster or paint
Lifting or warping floorboards
Mould growth on interior walls
Damp patches and musty smells indoors
How to Stop Rising Damp on External Walls
If you spot any of these signs, it’s crucial to act quickly. Here’s how rising damp on external walls is treated and prevented:
Identify the Source of Moisture First, locate and fix any issues contributing to damp, such as broken gutters, leaking drainpipes, poor drainage, or ground levels that are too high against the wall.
Install a Chemical Damp Proof Course (DPC) One of the most effective ways to treat rising damp is injecting a chemical DPC into the wall at the correct level. This creates a waterproof barrier, preventing moisture from rising through brickwork.
Lower External Ground Levels If soil or paving is bridging the DPC or built up against external walls, removing excess soil can stop moisture from bypassing the barrier.
Replace Damaged Masonry or Plaster In severe cases, removing and replacing saturated bricks, mortar, or plaster is necessary to eliminate trapped moisture and prevent future issues.
Install a New Damp Proof Membrane In some cases, especially where no DPC exists, installing a new damp proof membrane below ground level can provide a long-term solution.
Improve Drainage Redirect water away from your home’s foundation with proper drainage, soakaways, or French drains.
Why Professional Help Matters
Rising damp is a complex problem that requires expert assessment and treatment. DIY solutions often mask the symptoms rather than addressing the underlying cause — leading to repeat problems and wasted money.
At Henderson Wood, we provide:
Detailed damp surveys using modern diagnostic tools
Clear explanations and honest advice about treatment options
Tailored damp proofing solutions designed around your property’s unique needs
Quality workmanship backed by guarantees for peace of mind
Protect Your Home Today
Don’t let rising damp compromise your home’s structure or your family’s health. Contact Henderson Wood today to arrange a damp survey and discuss the best way to treat damp on your external walls.