How to Get Rid of Dampness in a Room

There’s nothing worse than walking into a room that smells musty and feels damp. The air feels heavy, the paint looks tired, and no matter how much you clean, the smell just won’t go away. I know how frustrating that is — I see it all the time. Dampness doesn’t just make a room uncomfortable, it can cause serious damage to your walls, furniture, and even your health.

In Johannesburg and other parts of South Africa, damp rooms are extremely common, especially during our summer rains. Between roof leaks, high humidity, and clay-rich soil that holds water, moisture has many ways to sneak into your home.

In this guide, I’ll explain what causes dampness, how to fix it properly, what temporary steps you can take, and how to prevent it from coming back. My goal is to help you understand the problem, not just cover it up.

Why Rooms Become Damp in the First Place

Dampness in a room simply means there’s too much moisture trapped indoors. Sometimes it’s visible — peeling paint or mould — but other times it’s hidden, showing only as a musty smell or a cool, clammy feel in the air.

Here are the most common causes I come across:

• Poor ventilation: Air that can’t circulate traps humidity inside, especially in bathrooms and bedrooms.
  
  
• Leaking roofs, gutters, or plumbing: Even small leaks can constantly feed moisture into walls or ceilings.
  
  
• Rising damp: Groundwater traveling up through your walls because of missing or failed waterproofing.
  
  
• Condensation: Steam from cooking, bathing, or even breathing settles on cold surfaces.
  
  
• Blocked subsoil drainage: In heavy clay areas like Johannesburg, trapped groundwater can soak into foundations.
  
  

A few months ago, I helped a family in Fourways whose main bedroom always smelled damp after rain. They had repainted several times, but the smell kept coming back. When I inspected, I found the roof valley leaking directly onto the ceiling cavity. We resealed the valley with liquid rubber and added proper ventilation. Within a week, the smell was gone completely — no repainting needed.

How to Tell If Dampness Is a Serious Problem

Damp starts small but can grow into something serious if ignored. Here’s how to tell the difference between a minor moisture problem and one that needs professional help.

Signs of Surface Damp (Easy Fix):

• Slight musty smell after rain.
  
  
• Light condensation on windows.
  
  
• Minor paint discoloration or slight bubbling.
  
  

Signs of Structural Damp (Needs Professional Help):

• Persistent mould or black spots on walls and ceilings.
  
  
• Peeling or flaking paint.
  
  
• Swollen skirting boards or door frames.
  
  
• White salt marks (efflorescence) on plaster.
  
  
• Wet, cold patches that don’t dry out.
  
  

If you have children, elderly family members, or anyone with asthma or allergies, act quickly. Mould spores from damp rooms can trigger breathing problems and worsen sinus issues.

Step-by-Step – How I Get Rid of Dampness in a Room

Every situation is different, but my process always follows a logical sequence.

1. Identify the Source

I start by tracing where the moisture is coming from — roof, wall, floor, or air. Sometimes that means checking gutters or drainage outside, or using a moisture meter on interior walls.

2. Fix the Cause

No treatment will work until the source is eliminated. I repair leaks, adjust ground levels, clean gutters, or install subsoil drainage if needed.

3. Dry the Room Properly

Once the cause is fixed, I help the room dry naturally. That may mean opening windows, using fans or dehumidifiers, and letting sunlight in. In Johannesburg’s summer heat, most rooms dry within days once the water source is removed.

4. Treat Affected Surfaces

I strip off all loose plaster, clean any mould with an antifungal wash, and remove efflorescence. The wall is left clean and breathable before new coatings go on.

5. Restore and Repaint

After drying, I replaster using breathable materials and repaint with damp-resistant coatings that allow moisture to escape.

A few weeks ago, I worked on a lounge in Bryanston where the damp had spread halfway up the wall. We fixed the leaking roof joint, replaced the plaster with a breathable mix, and sealed the exterior with a cementitious coating. Six weeks later, the walls were completely dry — and the homeowner said the air in the room felt “lighter.”

Quick Fixes That Help (While You Tackle the Root Cause)

While you’re waiting to fix the main issue, a few small steps can make the room more comfortable:

• Improve airflow: Open windows and doors during dry hours to let moisture escape.
  
  
• Use dehumidifiers or moisture absorbers: These help draw water out of the air.
  
  
• Move furniture away from walls: Allows air to circulate and prevents mould growth.
  
  
• Avoid drying clothes indoors: It adds litres of moisture to the air daily.
  
  
• Clean surfaces with diluted vinegar or antifungal spray: Helps reduce mould temporarily.
  
  

Just remember, these are temporary fixes. They reduce symptoms but don’t eliminate the source of dampness.

The Main Types of Damp That Affect Rooms

Not all damp is the same — and each type requires a different approach.

Rising Damp

Caused by groundwater rising through the wall. You’ll see it low down, often near the skirting. It needs drainage or a new damp-proof course. See: How to Fix Rising Damp in Walls and Damp Wall Treatment: Causes and Solutions.

Penetrating Damp

Water entering through cracks, porous bricks, or roof leaks. The solution is external repair and waterproofing.

Condensation Damp

Caused by indoor humidity from cooking, showering, or poor ventilation. The solution is improved airflow and breathable materials.

Plumbing Leaks

A leaking pipe inside the wall can mimic all of the above. Proper inspection can confirm it quickly.

Long-Term Damp-Proofing Methods

Once the room is dry, lasting protection depends on choosing the right waterproofing method.

• Subsoil Drainage: Prevents groundwater from pressing against foundation walls.
  
  
• Roof Waterproofing: Stops rainwater from entering ceilings and walls.
  
  
• Wall Waterproofing Systems: Includes liquid rubber coatings, cementitious barriers, or torch-on membranes.
  
  
• Breathable Interior Plasters and Paints: Allow walls to “breathe,” preventing trapped moisture.
  
  

For specific roof guidance, see:

• Flat Roof Waterproofing Methods
  
  
• Tiled Roof Waterproofing Tips
  
  
• Metal Roof Waterproofing and Rust Prevention
  
  
• Torch-On Membrane vs Liquid Rubber
  
  

How Much Does It Cost to Fix a Damp Room?

The cost depends on the room size, severity, and treatment required.

Here’s a rough guide for Johannesburg homes:

• Minor condensation or surface treatment: R1,000 – R3,000
  
  
• Full wall waterproofing or replastering: R5,000 – R15,000
  
  
• Subsoil drainage or exterior membrane: R8,000 – R25,000+
  
  
• Roof leak and ceiling repair: R3,000 – R10,000
  
  

Investing in proper waterproofing is always cheaper than repairing repeated damage. For comparison, see How Much Does Roof Waterproofing Cost.

How to Prevent Dampness from Coming Back

The key to prevention is regular maintenance and airflow. Here’s what I recommend to every homeowner:

• Clean gutters and downpipes at least twice a year.
  
  
• Make sure soil slopes away from the house to prevent water pooling.
  
  
• Ventilate bathrooms and kitchens — even a small extractor fan helps.
  
  
• Repaint every few years using breathable, damp-resistant coatings.
  
  
• Inspect before rainy season for leaks or cracks.
  
  

Prevention costs little but saves thousands in repairs later. For more, see Roof Maintenance Tips to Extend Roof Lifespan.

When to Call a Professional

If you’ve cleaned, repainted, and aired the room out but it still smells damp, it’s time for a professional inspection.

When I’m called out, I perform a full diagnostic check:

• Measure wall moisture levels.
  
  
• Check drainage and roofing conditions.
  
  
• Inspect for cracks and leaks.
  
  
• Provide a written plan for treatment and prevention.
  
  

Most cases don’t need major reconstruction — just proper waterproofing and ventilation.

Final Thoughts

Damp rooms are incredibly common, but they’re never something you just have to live with. Whether it’s rising damp, condensation, or a hidden leak, there’s always a cause — and a solution.

If your bedroom, lounge, or bathroom always feels damp, don’t wait for it to spread. I offer free call-outs across Johannesburg — send me a message and I’ll take a look. Together, we’ll get your home dry, healthy, and comfortable again.

There’s nothing worse than walking into a room that smells musty and feels damp. The air feels heavy, the paint looks tired, and no matter how much you clean, the smell just won’t go away. I know how frustrating that is — I see it all the time. Dampness doesn’t just make a room uncomfortable, it can cause serious damage to your walls, furniture, and even your health.

In Johannesburg and other parts of South Africa, damp rooms are extremely common, especially during our summer rains. Between roof leaks, high humidity, and clay-rich soil that holds water, moisture has many ways to sneak into your home.

In this guide, I’ll explain what causes dampness, how to fix it properly, what temporary steps you can take, and how to prevent it from coming back. My goal is to help you understand the problem, not just cover it up.

Why Rooms Become Damp in the First Place

Dampness in a room simply means there’s too much moisture trapped indoors. Sometimes it’s visible — peeling paint or mould — but other times it’s hidden, showing only as a musty smell or a cool, clammy feel in the air.

Here are the most common causes I come across:

• Poor ventilation: Air that can’t circulate traps humidity inside, especially in bathrooms and bedrooms.
  
  
• Leaking roofs, gutters, or plumbing: Even small leaks can constantly feed moisture into walls or ceilings.
  
  
• Rising damp: Groundwater traveling up through your walls because of missing or failed waterproofing.
  
  
• Condensation: Steam from cooking, bathing, or even breathing settles on cold surfaces.
  
  
• Blocked subsoil drainage: In heavy clay areas like Johannesburg, trapped groundwater can soak into foundations.
  
  

A few months ago, I helped a family in Fourways whose main bedroom always smelled damp after rain. They had repainted several times, but the smell kept coming back. When I inspected, I found the roof valley leaking directly onto the ceiling cavity. We resealed the valley with liquid rubber and added proper ventilation. Within a week, the smell was gone completely — no repainting needed.

How to Tell If Dampness Is a Serious Problem

Damp starts small but can grow into something serious if ignored. Here’s how to tell the difference between a minor moisture problem and one that needs professional help.

Signs of Surface Damp (Easy Fix):

• Slight musty smell after rain.
  
  
• Light condensation on windows.
  
  
• Minor paint discoloration or slight bubbling.
  
  

Signs of Structural Damp (Needs Professional Help):

• Persistent mould or black spots on walls and ceilings.
  
  
• Peeling or flaking paint.
  
  
• Swollen skirting boards or door frames.
  
  
• White salt marks (efflorescence) on plaster.
  
  
• Wet, cold patches that don’t dry out.
  
  

If you have children, elderly family members, or anyone with asthma or allergies, act quickly. Mould spores from damp rooms can trigger breathing problems and worsen sinus issues.

Step-by-Step – How I Get Rid of Dampness in a Room

Every situation is different, but my process always follows a logical sequence.

1. Identify the Source

I start by tracing where the moisture is coming from — roof, wall, floor, or air. Sometimes that means checking gutters or drainage outside, or using a moisture meter on interior walls.

2. Fix the Cause

No treatment will work until the source is eliminated. I repair leaks, adjust ground levels, clean gutters, or install subsoil drainage if needed.

3. Dry the Room Properly

Once the cause is fixed, I help the room dry naturally. That may mean opening windows, using fans or dehumidifiers, and letting sunlight in. In Johannesburg’s summer heat, most rooms dry within days once the water source is removed.

4. Treat Affected Surfaces

I strip off all loose plaster, clean any mould with an antifungal wash, and remove efflorescence. The wall is left clean and breathable before new coatings go on.

5. Restore and Repaint

After drying, I replaster using breathable materials and repaint with damp-resistant coatings that allow moisture to escape.

A few weeks ago, I worked on a lounge in Bryanston where the damp had spread halfway up the wall. We fixed the leaking roof joint, replaced the plaster with a breathable mix, and sealed the exterior with a cementitious coating. Six weeks later, the walls were completely dry — and the homeowner said the air in the room felt “lighter.”

Quick Fixes That Help (While You Tackle the Root Cause)

While you’re waiting to fix the main issue, a few small steps can make the room more comfortable:

• Improve airflow: Open windows and doors during dry hours to let moisture escape.
  
  
• Use dehumidifiers or moisture absorbers: These help draw water out of the air.
  
  
• Move furniture away from walls: Allows air to circulate and prevents mould growth.
  
  
• Avoid drying clothes indoors: It adds litres of moisture to the air daily.
  
  
• Clean surfaces with diluted vinegar or antifungal spray: Helps reduce mould temporarily.
  
  

Just remember, these are temporary fixes. They reduce symptoms but don’t eliminate the source of dampness.

The Main Types of Damp That Affect Rooms

Not all damp is the same — and each type requires a different approach.

Rising Damp

Caused by groundwater rising through the wall. You’ll see it low down, often near the skirting. It needs drainage or a new damp-proof course. See: How to Fix Rising Damp in Walls and Damp Wall Treatment: Causes and Solutions.

Penetrating Damp

Water entering through cracks, porous bricks, or roof leaks. The solution is external repair and waterproofing.

Condensation Damp

Caused by indoor humidity from cooking, showering, or poor ventilation. The solution is improved airflow and breathable materials.

Plumbing Leaks

A leaking pipe inside the wall can mimic all of the above. Proper inspection can confirm it quickly.

Long-Term Damp-Proofing Methods

Once the room is dry, lasting protection depends on choosing the right waterproofing method.

• Subsoil Drainage: Prevents groundwater from pressing against foundation walls.
  
  
• Roof Waterproofing: Stops rainwater from entering ceilings and walls.
  
  
• Wall Waterproofing Systems: Includes liquid rubber coatings, cementitious barriers, or torch-on membranes.
  
  
• Breathable Interior Plasters and Paints: Allow walls to “breathe,” preventing trapped moisture.
  
  

For specific roof guidance, see:

• Flat Roof Waterproofing Methods
  
  
• Tiled Roof Waterproofing Tips
  
  
• Metal Roof Waterproofing and Rust Prevention
  
  
• Torch-On Membrane vs Liquid Rubber
  
  

How Much Does It Cost to Fix a Damp Room?

The cost depends on the room size, severity, and treatment required.

Here’s a rough guide for Johannesburg homes:

• Minor condensation or surface treatment: R1,000 – R3,000
  
  
• Full wall waterproofing or replastering: R5,000 – R15,000
  
  
• Subsoil drainage or exterior membrane: R8,000 – R25,000+
  
  
• Roof leak and ceiling repair: R3,000 – R10,000
  
  

Investing in proper waterproofing is always cheaper than repairing repeated damage. For comparison, see How Much Does Roof Waterproofing Cost.

How to Prevent Dampness from Coming Back

The key to prevention is regular maintenance and airflow. Here’s what I recommend to every homeowner:

• Clean gutters and downpipes at least twice a year.
  
  
• Make sure soil slopes away from the house to prevent water pooling.
  
  
• Ventilate bathrooms and kitchens — even a small extractor fan helps.
  
  
• Repaint every few years using breathable, damp-resistant coatings.
  
  
• Inspect before rainy season for leaks or cracks.
  
  

Prevention costs little but saves thousands in repairs later. For more, see Roof Maintenance Tips to Extend Roof Lifespan.

When to Call a Professional

If you’ve cleaned, repainted, and aired the room out but it still smells damp, it’s time for a professional inspection.

When I’m called out, I perform a full diagnostic check:

• Measure wall moisture levels.
  
  
• Check drainage and roofing conditions.
  
  
• Inspect for cracks and leaks.
  
  
• Provide a written plan for treatment and prevention.
  
  

Most cases don’t need major reconstruction — just proper waterproofing and ventilation.

Final Thoughts

Damp rooms are incredibly common, but they’re never something you just have to live with. Whether it’s rising damp, condensation, or a hidden leak, there’s always a cause — and a solution.

If your bedroom, lounge, or bathroom always feels damp, don’t wait for it to spread. I offer free call-outs across Johannesburg — send me a message and I’ll take a look. Together, we’ll get your home dry, healthy, and comfortable again.