Condensation….10 top tips to prevent it happening in your property!

Condensation – a timely reminder and 10 useful tips

Failing to address tenant’s concerns could lead to health issues, non-payment of rent, and even a fine. Many tenancy agreements say that the landlord is responsible for keeping the property ‘fit to live in’ or ‘in good condition’. That sort of term may be broken if there’s dampness and mould growth, and condensation.
What is condensation?

Condensation is formed when warm air, holding water vapour, comes into contact with a cold surface.  The air near to the cold surface cools and the cooler air is unable to hold as much water vapour as it was able to when it was warmer.
The water vapour that the cooler air is unable to hold is deposited on the adjacent cool surface.
Condensation will appear where rooms are cold and inadequately heated and ventilated, thereby creating lots of cold surfaces.  The production of too much steam from cooking, washing, showering, drying of clothes etc. will result in moisture-laden warm air which rises to the highest and coldest parts of the house and result in condensation.
Some case studies on how cases of condensation were solved:

  • Black mould had formed on the ceiling and upper walls in a small pantry, adjacent to the kitchen in a cottage, caused by the warm air in the room coming into contact with the cold surfaces and forming water vapour.  In this case a specialist company was engaged to thoroughly clean the surfaces with water mixed with bleach to remove all traces of the black mould and a specialist cold wall coating was applied.
  • A ground floor flat appeared damp, the wall paper was peeling off the walls and droplets of water formed on the underlying surface caused a distinct ‘tide mark’.  The render was analysed and proved to be water resistant, moisture analysis showed the wall was basically “dry” therefore rising damp was not the cause.  There was no ventilation in the property and the windows were double glazed.  Further investigation revealed that the dampness and decorative spoiling were solely due to severe localised condensation on the lower part of the cold external walls.  To solve the problem, the tenants were given a dehumidifier, required to leave ventilation strips in the windows open and to adequately heat their property.
  • A bungalow was suffering from very severe condensation, with black mould and damp areas on most walls.  It was also very poorly insulated, so heat loss was a significant problem with high fuel bills being a major concern.  The tenant was putting damp washing out to dry in the kitchen, the bath and shower were used without an extractor or ventilation. The situation was rectified by improving the insulation in the property and reducing the humidity by having extractor fans fitted in the kitchen and bathroom.  These measures reduced the heating bills and reduced the source of the condensation.
  • A period, end of terrace house suffered from damp and condensation.  As it did not have cavity wall insulation and the loft had been converted into a bedroom, there was limited scope to insulate the property adequately.  The home was occupied by a family of four and it was obvious that there was insufficient ventilation in the home.  There was clearly an imbalance between the moisture being produced from normal family activities against the amount that was being removed through natural ventilation.  This was remedied by adding air bricks into the cellar walls along the side of the house to bring air into the cellar.  By ventilating the cellar, the floor timbers were able to dry out.  Insulation was installed between the cellar and the first floor with a breathable membrane to stop draughts from the cellar cooling the first floor.  Heat recovery ventilation units were installed on the ground and first floors to provide a constant flow of air – these are particularly effective as they remove stale air and draw in fresh air from outside.

10 tips on preventing condensation

As condensation is a problem in so many let properties, it is usual to expect a clause in the Tenancy Agreement requiring the tenant to adequately heat and ventilate the property.  The landlord or agent can then enforce this on their inspections, but should also respond quickly on tenants complaints.

  • Educate the tenant on the causes of condensation (and include a clause in the Tenancy Agreement)
  • Maintain a constant temperature in all rooms of about 12c
  • Minimise the amount of steam produced when cooking and washing, and always vent this to the outside.  Keep internal doors closed
  • Avoid drying wet clothes on radiators and make sure tumble dryers have an external vent
  • In modern homes, keep the trickle ventilation open at all times.  In older homes, ensure windows are kept open when possible
  • Wipe down and clean surfaces to stop the build up of mould growth or damage on areas where condensation does occur
  • Consider putting in air bricks
  • Check out the cold spots in the property and ensure adequate heating and ventilation in that area
  • Suggest that the tenant uses a dehumidifier unit – for a relatively small capital outlay the savings in heating bills and improved comfort should be worthwhile
  • Consider using thermal paints and condensation damp treatments in difficult cold areas

For further discussion on matters of condensation, mould and ventilation call either Andrew or Chris on 01284-702626 or email