Condensation

This is the most common cause of dampness people experience in their rented homes. Most people will see black mould or water droplets and assume there is a water leak, or it has come from outside - it hasn’t!

 

What is it?

Condensation occurs when moisture or water vapour in the air meets a colder surface, such as a window, wall, or mirror. When this happens water droplets (condensation) can soak into the surface they touch. Mould spores may then land on these damp areas causing mould growth. Mould is a common fungus that grows on clean water, for example, untreated condensation.

 

How is it caused?

Condensation and mould growth are often due to the lifestyle of the inhabitants. Simple changes to their actions or activities can reduce the amount of moisture in the air.

 

A properly ventilated and heated property is also less likely to have these issues. When the external temperature is low, such as during the colder months, condensation is more likely to occur. This is because cold air cannot hold as much moisture as warm air.

 

Where is it found?

It is usually found on:

• The corners of rooms

• Cold external walls

• On or around windows

• Areas of poor air circulation such as behind furniture or inside wardrobes

• Sometimes it can be at skirting board or ceiling level where the junction of two internal walls meet

 

How to spot condensation

• Damp patches with no clear edges

• Staining from running water

• Crescent shape (at skirting board or ceiling level where the junction of two internal walls meet)

• Mould growth

• Musty smell

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Rising Damp

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This is commonly caused when water from the ground rises into the home.

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What is it?

This is caused by ground water moving up through a wall or floor.

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How is it caused?  

Water from the ground rises into the home by either passing though the brickwork or concrete of the property if there is no damp-proof course (DPC) or the DPC is broken.

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Where is it found?

Rising damp will only affect basements and ground floor rooms in a home, up to a height of about 1 metre.

 

Older homes are more vulnerable to rising damp.

 

How to spot Rising Damp

• ‘Tide mark’ low down on the wall (above skirting board) that rises up

• Wet patches on walls

• Peeling paint or lifting wallpaper

• A white powdery substance on walls (salts)

• Wall plaster may be crumbling

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It will be seen all year round but is more noticeable in winter.

It is rare to see black mould on rising damp as this type of dampness carries with it ground salts which are poisonous to black mould.

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Penetrating Damp

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It is typically caused by rain penetrating the structure of a building. The rainwater can soak through the external structure of the building and travel to internal walls and ceilings.

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What is it?

It occurs when there are defects to your property on the outside such as missing tiles on your roof. These allow water to pass from the outside to the inner surfaces of your home such as ceilings or walls.

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How is it caused?

It is normally a result of a defect outside your home such as:

• Missing roof tiles

• Blocked/defective rainwater goods

• Missing pointing

• Cracked rendering

• Gaps around doors and windows

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Where is it found?

It can be found in different areas of your home. For example, there may be penetrating damp to the ceiling caused by a leaking roof or on an external wall due to a defective guttering causing water to run down the wall.

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How to spot Penetrating Damp

• It usually appears as an obvious ‘damp patch’ that will look and feel damp to the touch.

• There may be damage to decoration, plaster, and walls.

• Penetrating damp is far more noticeable following rainfall.

It is rare to see black mould on areas of penetrating damp as the area is usually too wet. The damp area contains salts which are picked up as the water passes through the surface. These salts stop black mould from growing.

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Damp caused by Defective Plumbing

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This is when there is damp inside your home because of a leak from water and waste pipes.

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What is it?

This type of damp happens when a water and/or waste pipe has a leak releasing the water/wastewater inside your home. For example, a leak from the waste pipe under the bath could cause

a leak through the ceiling into the room below.

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How is it caused?

It is caused by leaks from water and waste pipes in the home, and can affect both internal and external walls and ceilings

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Where is it found?

• Water pipes

• Waste pipes

• Bathrooms – defective sealants around bath, shower, and sinks

• Kitchens - sink

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How to spot Defective Plumbing

• The area will look and feel damp to the touch.

• The area will remain damp whatever the weather conditions.

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A quick examination of the water and waste pipes serving the kitchen and bathroom, as well as the seals around the bath, shower and sinks will usually locate the source of the problem.

It is rare to see black mould on areas of damp caused by defective plumbing as the area is usually too wet and the wastewater is poisonous which stops mould from growing.

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