3. Condensation, Rising damp & Penetrative damp

Image showing condensation


Condensation occurs when warm moist air meets a cold surface; the risk of condensation therefore depends on how moist the air is and how cold the surfaces of the room are. Both of these depend on how a building is being used. Condensation can lead to staining and mould growth damaging wallpaper, wall surfaces, window frames, furniture and clothing. Condensation occurs usually in winter because the building structure is cold and windows are opened less meaning moist air cannot escape.


The most vulnerable areas will be rooms where a large amount of moisture is produced i.e. the bathroom and the kitchen, or on cold surfaces in other rooms where the rooms are unheated. Condensation is also commonly found in areas where pockets of air become stagnant, for example behind furniture pushed right up against the wall which does not allow air to circulate behind it.


Condensation is the tenant’s responsibility to manage and here are some tips on how to do so:


Keep the heating on low as much as possible, leaving some windows open to ventilate rooms. This will ensure the right balance between heating and ventilation will be met and will help remove some of the moisture form the air. Keeping heating on low constantly may also be cheaper than using it at high temperature is short blasts. Keep furniture away from walls to allow air to circulate behind it. Use lids to saucepans to minimise water vapour escaping in the air. Dry washing outside, however if this is not possible leave a window open in the room to allow moisture to escape and close the door. Open windows in humid rooms and close the door to the rest of the house, this will prevent the moisture spreading into other rooms. Keep wiping down wet areas, if any are showing signs of mildew wipe them over with a fungicidal solution, inexpensively purchased from DIY stores or supermarkets to kill the spores, this prevents re-growth too.


Rising Damp


Rising damp is caused when moisture from the ground spreads into brickwork rising through tiny cracks in the masonry. It is usually found up to around the first metre of the wall. It commonly occurs when the damp course separating the foundations and the brickwork is cracked, or when the damp protection is “bridged”, for example where the flowerbed or patio outside etc rises above the damp course.


Rising damp differs from condensation because the moisture is drawn from the floor upwards and inwards, whereas condensation forms on the insides of walls and soaks outwards. Damp displays different patterns to condensation as very little mildew may grow, but its presence will be made obvious by large “tide marks” or the “tea bag stain” effect. Rising damp is less common than often thought, but where it does occur it is the Landlord’s responsibility.


Penetrative Damp


Penetrating damp is caused by moisture which penetrates through the roof or walls. It is usually very difficult to pinpoint and cure the precise cause of the problem and very often there is no quick or easy solution. Penetrating damp can sometimes be caused by gutter or roof problems e.g. blockages which allow rainwater to spill onto and saturate areas of exterior walls, which then soak through the walls causing obvious damp patch and paintwork to blister and flake.


As with rising damp there may be very little mildew present, however it may still occur due to the moisture which will encourage fungi to grow. As penetrative damp is a structural problem it is the Landlord’s responsibility to rectify.


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