What is The Difference Between Rising Damp and Condensation

What is The Difference Between Rising Damp and Condensation

While different types of damp might appear similar in your home, it is vital to be able to tell the difference between them if you want to remove the problem.

The Different Types of Damp

There are two causes of damp in a home:

• Damp which is caused by condensation from within the house.
• Damp which is caused by water entering from outside the home.

Damp from external sources includes rising damp from the ground, rainwater leaks, poor drainage, or defective plumbing.  Condensation damp is caused by the humidity in your home from cooking, bathing, and breathing.  Typically, condensation damp gets worse in cold weather as airborne humidity is more likely to condense on walls and windows when it is cooler.  By comparison, other types of damp such as rising damp typically become worse in wet weather.

You can often tell what is causing damp by its appearance.  Condensation tends to form patches of mould with soft edges rather whereas other types of damp cause a stain mark to appear on walls, ceilings, or floors.

Why Damp is a Problem

Damp can cause a variety of problems in your home and needs to be treated as quickly as possible.  Long term damp issues can cause window frames, floors, and skirting boards to rot and cause plaster to flake from walls.  In the shorter term, dampness causes mould and encourages the growth of house dust mite populations.  Both mould and dust mites can increase problems with allergies and respiratory illness.

What Causes Rising Damp

Rising damp is caused by the ingress of water from the ground into the walls of your home.  Modern buildings include a damp course layer – a plastic barrier in the walls – which is designed to stop bricks from sucking the water up from damp ground.  Without a damp course, the capillary action of small cavities within bricks and cement draws water out of the ground like a sponge and holds it in the structure of the building material.

Typically rising damp can only rise to about 1.2 metres above the ground before gravity prevents it getting any further. 

This limit in how far the damp can rise will often lead to a clearly defined damp stain being visible on walls inside your home.

In the damp conditions of an affected wall, mould spores can gain a foothold and you will often see the growth of mildew or dangerous black Stachybotrys mould in affected areas.  This needs to be treated quickly as it is a major health risk.

Condensation Damp

Condensation is caused when humid air meets cold surfaces like walls and windows.  As the temperature goes down, the amount of moisture that the air can hold falls and the tiny drops of water form on the surface.

The air in your home is naturally moist, but the amount of moisture is increased by the release of water vapour from cooking, bathing, and showering and even respiration.  If condensation is allowed to sit on walls for long periods of time, it can penetrate the outer layers of your walls and seep into furniture where it becomes a longer-term problem, causing mould to grow.

Steps to Reduce Condensation

Condensation damp is highly preventable, and there are steps that you can take to reduce the risk immediately. 

• Dry clothes outdoors
• Close the kitchen and bathroom doors during use
• Ensure that you use extractor fans and pan lids when cooking
• Use an extractor fan when bathing
• Leave windows open during warmer weather
• Ensure that furniture is placed at least 2 inches away from external walls
• Avoid overfilling wardrobes and cupboards

If your home suffers from persistent condensation problems and unsightly damp patches, then you may need to review your current ventilation system to ensure that it is sufficient to allow for good airflow.  Extractor fans play an important role in ventilation but older devices do need to be replaced every 5 to 10 years as their motors can wear out and they can become clogged.

Treating Condensation and Damp

Treating the condensation that can lead to damp in your home might be easier than you think.  Installing filterless extractor fans in your bathroom and kitchen that automatically adjust their power levels depending on humidity can reduce condensation problems quickly. 

Almost 1 in 5 UK homes have a problem with condensation that can lead to damp and mould, but by taking the right action, you can resolve issues with condensation forever.  Arrange a free home survey from one of EnviroVent’s local specialists who can advise you about how proper ventilation can benefit your indoor air quality and reduce damp.