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Rising Damp in Walls
Does my home have rising damp? How do I know what’s causing it?
Rising damp refers to the unwanted moisture that gets stuck in the structure of your home. It occurs because the capillaries in porous masonry, such as stone, mortar or brick, suck up water from the ground they sit on. Even modern air-fired bricks have this problem, soaking up ‘damp’ like a sponge.If your home’s masonry soaks up too much moisture (and damaging salts) with no way for it to drain, you’ll encounter some serious issues. Left untreated, the damp can become a threat to the structural integrity of your home, your health and the health of your family.If you want to learn how to identify rising damp and its causes, read on below.
What are the signs of rising damp?
Flaking and Blistering Paint
One of the most visible signs of rising damp is flaking, blistering or powdery paint. Paint needs a dry surface to adhere, but damp works against this. As your porous masonry walls absorb water, the walls become drenched with liquid, salts and minerals. This damp disrupts the painted finish on surfaces, causing major damage to the protection and aesthetics of your walls.
Yellow or Brown Tide-like Stains
If your walls are showing yellow, wavy, tide-like stains, it’s likely you have a rising damp issue. When moisture in your masonry has a chance to dry, it leaves behind salts and minerals. These are what cause the ugly stains. But don’t be fooled–this is only surface-level drying. If you see stains, it’s a big warning sign that your walls are soaked through and damaged on the inside.
Structural Damage
Structural damage caused by rising damp can be easy to spot in your walls. After drawing up water, your masonry will contain trapped salts and minerals. Over time, these salts and minerals will expand, forcing their way out of the masonry from the inside. This will eat away at the mortar joins between bricks and disintegrate masonry into dust, turning your home’s walls into a crumbling mess.
Mould
Deep down in the foundations of your home, the moisture that your porous masonry has drawn from the ground has nowhere to escape. As a result, it doesn’t dry out naturally. This can cause the base of both your interior and exterior walls to develop a dark green or even black mould. If you spot mould localised around the base of your interior walls, the likelihood of rising damp is high.
Flaking and Blistering Paint
One of the most visible signs of rising damp is flaking, blistering or powdery paint. Paint needs a dry surface to adhere, but damp works against this. As your porous masonry walls absorb water, the walls become drenched with liquid, salts and minerals. This damp disrupts the painted finish on surfaces, causing major damage to the protection and aesthetics of your walls.
Yellow or Brown Tide-like Stains
If your walls are showing yellow, wavy, tide-like stains, it’s likely you have a rising damp issue. When moisture in your masonry has a chance to dry, it leaves behind salts and minerals. These are what cause the ugly stains. But don’t be fooled–this is only surface-level drying. If you see stains, it’s a big warning sign that your walls are soaked through and damaged on the inside.
Structural Damage
Structural damage caused by rising damp can be easy to spot in your walls. After drawing up water, your masonry will contain trapped salts and minerals. Over time, these salts and minerals will expand, forcing their way out of the masonry from the inside. This will eat away at the mortar joins between bricks and disintegrate masonry into dust, turning your home’s walls into a crumbling mess.
Mould
Deep down in the foundations of your home, the moisture that your porous masonry has drawn from the ground has nowhere to escape. As a result, it doesn’t dry out naturally. This can cause the base of both your interior and exterior walls to develop a dark green or even black mould. If you spot mould localised around the base of your interior walls, the likelihood of rising damp is high.
What are the leading causes of rising damp?
A Corroded Membrane
During the initial construction phase of your home, builders install damp proof coursing inside the walls. This acts to shield porous masonry from moisture and salts, stopping rising damp in its tracks.
However, few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic, slate or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
Poor Drainage
Broken and leaking pipes, unconnected downpipes, leaking roof gutters and overflowing stormwater drains can all be causes of rising damp. Instead of directing water away, malfunctioning pipes cause water to pool around and into the foundations of your home. This excess water has nowhere to escape but into the thirsty masonry, causing rising damp.
You can also experience the same issues if your home is at the bottom of a slope, or if the ground level has been raised higher than the original damp proof coursing level. Without an effective drainage system to run off rainwater and flooding, your home will be at risk.
Poor Subfloor Ventilation
A consistently well-ventilated home can keep the superficial effects of rising damp at bay–for a while. It will help to slow down the rate of decay, but it won’t cure it. But if your home has poor ventilation, then it is on the quick track toward serious rising damp damage.Without adequate subfloor airflow, even more moisture gets trapped around your foundations, waiting to be absorbed by the masonry. This will accelerate the spread of rising damp and the severity of its effects.
Wrong Barrier Height
If your home suffers from rising damp, the issue may date back to its original construction. Over the years, perceptions of rising damp and how to protect against it have varied widely. In many older homes, it’s common to find damp-proof barriers, such as slate and bitumen, installed higher up on walls than necessary.
Due to gravitational forces, rising damp typically does not exceed one metre in height. Therefore, for a damp-proof barrier to function effectively, it must be positioned just above ground level.
Due to gravitational forces, rising damp typically does not exceed one metre in height. Therefore, for a damp-proof barrier to function effectively, it must be positioned just above ground level.
Bridging
In construction terminology, “bridging” refers to the phenomenon where water or moisture bypasses damp-proof barriers or penetrates through walls. This often occurs as landscape levels change over time, leading to unintended bridging. If you have recently installed a new path or patio on your property and subsequently begin to observe symptoms of rising damp, such as moisture on your walls, it is likely that bridging is the culprit.
Membrane Corrosion
During the initial construction phase of your home, builders install damp proof coursing inside the walls. This acts to shield porous masonry from moisture and salts, stopping rising damp in its tracks.
However, a few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
However, a few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
A Corroded Membrane
During the initial construction phase of your home, builders install damp proof coursing inside the walls. This acts to shield porous masonry from moisture and salts, stopping rising damp in its tracks.However, few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic, slate or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
Poor Drainage
Broken and leaking pipes, unconnected downpipes, leaking roof gutters and overflowing stormwater drains can all be causes of rising damp. Instead of directing water away, malfunctioning pipes cause water to pool around and into the foundations of your home. This excess water has nowhere to escape but into the thirsty masonry, causing rising damp.You can also experience the same issues if your home is at the bottom of a slope, or if the ground level has been raised higher than the original damp proof coursing level. Without an effective drainage system to run off rainwater and flooding, your home will be at risk.
Poor Subfloor Ventilation
A consistently well-ventilated home can keep the superficial effects of rising damp at bay–for a while. It will help to slow down the rate of decay, but it won’t cure it. But if your home has poor ventilation, then it is on the quick track toward serious rising damp damage.Without adequate subfloor airflow, even more moisture gets trapped around your foundations, waiting to be absorbed by the masonry. This will accelerate the spread of rising damp and the severity of its effects.
Wrong Barrier Height
If your home suffers from rising damp, the issue may date back to its original construction. Over the years, perceptions of rising damp and how to protect against it have varied widely. In many older homes, it’s common to find damp-proof barriers, such as slate and bitumen, installed higher up on walls than necessary.
Due to gravitational forces, rising damp typically does not exceed one metre in height. Therefore, for a damp-proof barrier to function effectively, it must be positioned just above ground level.
Due to gravitational forces, rising damp typically does not exceed one metre in height. Therefore, for a damp-proof barrier to function effectively, it must be positioned just above ground level.
Bridging
In construction terminology, “bridging” refers to the phenomenon where water or moisture bypasses damp-proof barriers or penetrates through walls. This often occurs as landscape levels change over time, leading to unintended bridging. If you have recently installed a new path or patio on your property and subsequently begin to observe symptoms of rising damp, such as moisture on your walls, it is likely that bridging is the culprit.
Membrane Corrosion
During the initial construction phase of your home, builders install damp proof coursing inside the walls. This acts to shield porous masonry from moisture and salts, stopping rising damp in its tracks.
However, a few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
However, a few damp courses will last forever. Over time and through wear and tear, the bitumen, plastic or tin membrane will naturally corrode. This lets water and salts back into your walls, triggering rising damp issues in places where you may have had none before.
Need a solution for rising damp?
Is your home drowning in rising damp? Our solutions save you time, money and stress.
Is your home drowning in rising damp? Our solutions save you time, money and stress.
