Damp-the inside view 1

Menasche Scharf takes us on a tour of the house to check for damp

 

 

 

In my article “Damp Dangers” I outlined the effects of a damp environment on our health. Here, the focus switches to the building structure itself. When buildings suffer damp, either by way of rainwater penetration or through rising damp from the ground, the materials the structure is comprised of may become compromised. This damage may show itself both externally and internally. In the very worst of cases it could cause the property to become unstable and therefore dangerous to live in.

 

External damp damage

 

As most damp problems originate from outside the building, damage to external walls tends to become evident before any effects are detected internally. Usually, damp penetrates through defective brickwork, pointing and stonework. If brick faces are decayed because of long-term exposure to the elements, they will allow moisture to enter the brickwork and take up residence in the property's structure. As well as the obvious entry points for moisture in the walls -- i.e. cracked or broken bricks / stones / render -- look out, too, for rebated mortar joints; blown, cracked and shelled brick faces, and algae attaching itself to the surface of brickwork. These are all sure-fire signs that moisture is entering the property structure.

 

Once inside the walls moisture begins to eat away at the integrity of the structure. Freeze-thaw of moisture in the winter is a particular problem as water expands in volume when frozen. Repeated freeze-thaw systematically destroys external walls, widening the gaps in which moisture can enter the building, so helping the damp to drive inwards to internal walls.

 

Internal damp problems

The first sign of damp trouble inside a property is normally found on the inside of westerly and southerly facing external walls - in our parts of the world, which is in the Northern hemisphere. Rainwater driven in from outside penetrates to the inner wall, often breaking down plaster into cracks and flakes and allowing mould to develop on the internal wall surface. When this happens you know you've got a problem!

 

High humidity coupled with poor ventilation promotes mould growth in damp areas of a property. In the winter, when the room temperature is high, particularly in smaller rooms or spaces that do not have windows to allow fresh air flow, mould takes hold quickly, discolouring and damaging the surface on which it grows.  Remember: fungus likes damp, dark places where it can grow safely, as exposure to air for long periods means it cannot dry out easily.