Damp damages most structural materials and all forms of decoration. It may result in an unhealthy atmosphere and make a home feel cold and cheerless. Regular maintenance can generally prevent it.
There are three main causes, Structural faults, leaks and condensation.
These may occur in the walls, floors, roof, chimney stacks and both door and window frames.
The damp-proof course – generally called DPC – is an impervious layer set horizontally in the house walls at least 6 inches above the soil level – most evident during wet weather. Even if the DPC is sound. It may be bridged by water splashing above it. Make sure that heaped soil, rock gardens and stored building
Materials are not allowed too close to it and that paths are not built too high against house walls.
Gaps around the windows and doors
Timber shrinks when it becomes dry and gaps may appear between frames and masonry. Seal with a flexible mastic compound.
Internal damp patches under a window may be due to a fault on the ledge outside. There should be a lip or groove on the underside to ensure that rain drips off it. If this is damaged or filled with paint rainwater may seep into the wall.
Missing or damaged slates and tiles
Displaced or damaged slates and tiles, and damaged felt or flat roofs, can allow water to enter a roof causing stains on the ceiling.
The best time to find faults is during heavy rain, when water can be traced back to their source. Sometimes the water will travel for a distance along roof rafters, and the damp patches may appear some way from the point of entry. Replace missing or damaged slates and tiles. Repair minor felt damage with bituminous mastic, but replace the felt completely if it becomes brittle and cracks.
Damage to Chimneys
This generally shows as damp areas on chimney breasts in bedrooms, which may stain the wall paper or cause mold. The trouble stems from porous brickwork, damaged or missing pointing, damaged flashing's or damaged flaunching. Seal porous brickwork with silicone water repellent. Replace damaged pointing and cap the flue if it is not in use. You don`t want to see the start of mildew or mold.
The seal between roof and stack – is a common cause of damp. If the fault is only a small crack or gap, seal with bituminous mastic. More extensive damage can be repaired with a pliable sheeting which can be softened with heat.
Damp may sometimes be caused by cracked flaunching – mortar bedding in which chimney pots are set. Replace with a 3 to 1 mix of sand and cement. Fill minor cracks with mastic or cover the flaunching with a fresh layer of mortar.
This is seen in the first place as fine water droplets on cold surfaces, such as window panes and outside walls. In severe cases it may also affect clothing in wardrobes, carpets and other soft furnishings, leading to mould growth and musty smell.
Condensation on floor coverings is sometimes mistaken for rising damp, and the wrong remedy applied. An almost infallible pointer to condensation is when an external wall becomes damp during cold, dry weather.
Condensation occurs when warm air, holding moisture, comes into contact with a cold surface. He warm air in a bathroom for instance, may be charged with vapour which becomes visible only when it touches a cold surface, such as a window. Here, the excess moisture is on the window pane as tiny droplets.
When a house is double-glazed excess water is more likely to be shed on cold wall surfaces.
There are four ways to prevent condensation: 1. Get rid of moist air by fitting an extractor fan or static ventilator.
2. Increase the room temperature, if necessary warming a particularly cold wall with an electric tubular heater. Do not use paraffin or flue less gas heater.
3. Fit double-glazing to windows. Improve the insulation of cold walls by covering with expanded-polystyrene veneer before wall papering.
4. Avoid creating water vapour by leaving kettles on the boil, or water in bowls.
How to get rid of Mildew
Getting rid of Mildew can be quite easy, you need to stop where the cold and damp is coming in or settling before you can get rid of Mildew, when everything is dry you can firstly clean the Infected area with a good domestos then once dried paint or brush the dried up mildew away, avoiding spreading the pores everywhere, if possible don't Inhale.