Damp and mould growth is often mistaken for leaks or building defects. In most cases, it is condensation that causes them and can effect anyone, from homeowners to tenants. Explore this page to learn more about damp, mould and how to manage moisture in the home.

Condensation

Condensation happens when warm moist air comes into contact with a cold surface like a wall or window.

The following can all cause condensation because they produce warm moist air:

  • cooking
  • washing
  • drying clothes indoors
  • boiling kettles

The problem is worse in rooms where heating is not used because the surfaces in those rooms will be colder.

All homes can suffer from mould growth. It is important to remove it with a suitable cleaning fluid as soon as you notice it, to avoid it spreading.

Damp, Mould and a Healthy Home: What Every Tenant, Landlord, and Homeowner Should Know

Moisture balance calculator 

The UK Centre for Moisture in Buildings (UKCMB) have developed a Moisture Balance Calculator. The tool is an interactive application for estimating the moisture balance of a house, based on answers to questions about moisture generation, occupancy, heating, ventilation and maintenance. If the home moisture is out of balance, easy actions can be explored to regain moisture balance.

View moisture balance calculator tool 

For more information please visit UKCMB or watch the video below.

Learn more about mould in the home

 
 

UKCMB

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Email: ukcmb@ucl.ac.uk 
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Other types of dampness in the home

If condensation is not the cause of unwanted moisture in your home, the problem could be damp. Black mould growth is very uncommon with damp. If you have black mould in your home, it is likely you have a problem with condensation.

For more information on mould, please visit UK Centre for Moisture in Buildings - A bit more information about mould.

Rising damp

Rising damp is caused by water coming up through the ground into your home. To cause damp, rising water needs to pass through the damp-proof course (DPC)

A DPC is a layer of waterproof material to stop ground moisture from rising through the walls. It can only do if the DPC is broken or if your home doesn’t have one.

Rising damp only affects basements and ground floors, and normally rises no more than 12 to 24 inches. You can often identify rising damp by a tide mark.

Penetrating damp

Penetrating damp occurs when water leaks in through a wall or roof. Common causes include

  • rain seeping in through a broken or missing roof tile
  • rain spilling from a blocked gutter during heavy rain
Faulty plumbing

Leaks can sometimes happen from water or waste pipes in the kitchen or bathroom. You can find the cause of the problem by checking the seals around baths, showers, sinks or pipework.

If you notice a leak or if a pipe in your home has burst, please tell us straight away. You should also:

  1. turn off your water and drain your system
  2. turn on all the cold taps and flush your toilet
  3. turn off your heating system and the system by turning on all the hot taps
  4. turn off the main power if the leak is close to any electric
  5. collect leaking water in buckets or pans
  6. if your ceiling starts to bulge from a leak above, use a long tool to release the water into a large bucket

Contents insurance

We strongly recommend that tenants take out home contents insurance. This protects your belongings in the event of a fire, flood or accident.

Additional information

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