Sydney’s Specialists In Rising Damp Solutions
Rising Damp Explained
How Rising Damp Happens.
Here Are The Symptoms of Rising Damp
- Sweating walls during wet weather
- Render that is progressively deteriorating
- Mortar between bricks becoming soft or powdery
- Bricks themselves slowly breaking down
- When you paint the walls, the paint doesn’t dry properly
Rising Damp can occur alongside mould problems because the source of both issues is the same — damp soil.
- You can experience both a mould issue caused by moisture under timber floors and masonry damage caused by a failed damp course in your walls. This happens when Rising Damp carries salts upward through the masonry, depositing them above the failed barrier and leading to surface decay.
- If your home is built on a concrete slab, you can still have Rising Damp — particularly if it’s an infill slab.
- An infill slab is created when the builder pours the slab after the walls are built, meaning the wall footings remain in direct contact with the soil. This allows moisture and salts to rise through the masonry, causing damage to bricks and render.
- A properly designed Chemical Injection system combined with a quality membrane will resolve this issue and protect the structure long-term.
Rising Damp Chemical Injection — How the Treatment Works
A real-world demonstration of our rising damp injection process
We use more product than the competition to fully saturate the masonry.
This example shows injection into solid sandstock bricks. Different brick types require slightly different injection methods to achieve optimal product penetration and long-term performance.
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How Rising Damp Happens in Masonry Walls
Rising Damp Requires Three Ingredients: Water, Salt, and Evaporation
Water
The damage caused by Rising Damp is not from the water itself — the water is simply the carrier for dissolved salts. As moisture moves through the masonry by capillary action, it brings these salts along, leaving the wall damp.
Water is the vehicle; salt is the problem.
As professional waterproofers, we distinguish between dampness and wetness. The two are very different. Water can cause flooding or leaks, but dampness causes long-term decay — it’s the slow crystallisation of salts that breaks down masonry from within.
Salt
The visible damage caused by Rising Damp is most often due to salt crystallisation, not the water itself.
When salt is either completely dry or completely wet, it remains stable. The problem occurs during the drying phase — as moisture evaporates, salt crystals grow within the microscopic pores and bonds between the sand and cement particles that form the masonry. These expanding crystals force the particles apart, breaking the bond that holds the wall together.
Once this bond is destroyed, the solid masonry begins to revert to its raw components — loose grains of sand and cement — which appear as fine masonry dust at the base of the wall.
In short: salt is the destroyer, and water is the vehicle that transports it upward through the wall.
Evaporation
The real catalyst behind the damage caused by Rising Damp is evaporation.
When masonry contains moisture mixed with dissolved salts, the water eventually evaporates — but the salts remain. Over time, these salts accumulate and crystallise within the pores of the wall, expanding and breaking apart the masonry structure. This is what turns your walls to dust and causes paint to bubble or flake.
In fact, increased evaporation actually accelerates the damage caused by Rising Damp. The faster the moisture evaporates, the faster salts are deposited and the more severe the deterioration becomes.
Evaporation is the engine that drives Rising Damp.
Here Are the Facts About Rising Damp
The Mechanics of Rising Damp in Masonry
Definition
Rising Damp is called Rising Damp because moisture starts at the base of the wall and slowly moves upward through the masonry.
Cause
Rising Damp rises due to a combination of capillary action, evaporation, and salts.
Capillary action and evaporation
Water rises through the pores of the masonry via capillary action until it reaches a height where evaporation occurs. As the moisture evaporates, dissolved solids — primarily salts — are deposited within the surface layers of the wall.
Salt accumulation feedback loop
These salts typically accumulate within the first 10mm above the floor or skirting board. As salt builds up, the pores of the masonry become blocked, restricting evaporation. Moisture then continues rising to the next point of least resistance, repeating the cycle.
Structural damage
As salts accumulate and crystallise, they physically expand, breaking down the masonry and causing deterioration.
End state
If left untreated, evaporation continues from salt-damaged areas until the wall surface eventually crumbles into dust. This process can take years, but it steadily weakens the structure.
Textbook Rising Damp rarely rises above 1 metre in height. If signs appear around 1.5–1.6 metres or higher — or near the ceiling — it’s likely a different issue, such as a leak, vent, air conditioning penetration, balcony junction, or crack, not true Rising Damp.
How Rising Damp Appears on Different Wall Finishes
- Rising Damp with exposed brick often shows as deterioration of the mortar joints. Over time, as the damage progresses, the bricks themselves begin to weaken and crumble.
- Rising Damp with render typically appears as bubbling paint — starting as small pimples — along with salt deposits, staining, and render breakdown into sand and cement dust.
Watch a 60-Second Rising Damp Injection (Time-Lapse)
The injection fluid saturates the target zone to create a continuous barrier through the masonry.
Rising Damp Treatments and Why the System Matters
Rising Damp has become a major industry over the past two decades, largely due to the ageing of buildings constructed with older materials and construction methods.
Today, there are many different Rising Damp solutions and products available, each with varying performance depending on wall type, construction method, and the extent of salt contamination.
Understanding how these systems differ — and where each one succeeds or fails — is critical to choosing the right long-term solution.
Read our guide to Rising Damp Products and Solutions to see how the main systems compare, and why some methods consistently outperform others — whether you choose us or another provider.
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