Rising damp in wet, windy winter weather

ThinkstockPhotos-476440779The likes of storm Abigail, the remnants of hurricane Kate and now storm Barney have swept across us recently. The Environment Agency currently has 10 flood warnings in place, which means “flooding is expected and immediate action is required”. The Met Office has issued further weather warnings for rain and wind in parts of Scotland, Northern Ireland and northern England. Forecasters have said that the damp and unsettled weather is the result of a series of low pressure systems moving in from the Atlantic.

Whilst we have huddled inside our homes away from the elements our properties have taken the brunt of the weather from torrential deluges and driving rain to gale force winds, with gusts of 85mph in Aberdaron and 79mph in Pembrey Sands according to the Met Office.

At first, we may not notice the long term damage our properties may suffer as the result of these repeated bouts of stormy, wet and windy weather. Excess water entering a building, can invariably cause damage to the structure and decorations.  One of the most common ways excess water damages a property is through rising damp. In most cases rising damp is fairly slow to develop and may be present for several years before the problem is highlighted by the appearance of damp patches.

BWater from the ground is drawn up into the pores of bricks, mortar and other materials used to construct walls and floors. The speed at which this process occurs depends on many things, including the nature of the ground, type of wall or floor construction and environmental conditions both inside and outside the building. There is often groundwater salts (Chlorides and Nitrates) dissolved in the rising water and as it evaporates, these salts become concentrated in the plaster and often leave a discoloured line that shows how far the water has risen.  These hygroscopic salts will absorb moisture out of the air (just like table salt) and make the wall surface damp.  When the air in the room dries, so does the wall.  Over time the damp patch appears and disappears, dependent on the weather.

Signs of Rising Damp

In general, signs of rising damp are evident to about a height of 1m (3.3 feet) in an average property. They include:

  • Damp patches on walls
  • Blistered paintwork
  • Stained and peeling wallpaper
  • Appearance of salt stains on outside walls
  • Mortar on the outside of the property begins to crumble away
  • Floor timbers are rotted by fungal decay

It is important to correctly distinguish between damage caused by rising damp and that caused by condensation or penetrating damp.  Correct diagnosis by a professional, specialist surveyor can prevent unnecessary expenditure on a solution that ultimately may not solve the underlying problem.

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