In my last article Damp Dangers I talked about the effects of damp environments on people's health. Here I want to switch the focus 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 residency 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 wintertime 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 it cannot dry out easily.
Independent of penetrating damp, but just as much of an issue is condensation, which again thrives in poorly ventilated rooms with moisture sources. WCs are particularly vulnerable here. For example a WC with a double radiator installed and no window is a recipe for disaster. Why? Because the cold water pipe from the mains, which passes through this room, creates a clash: the warm air hits the ice cold pipe, causing the air to condensate. If this happens around the clock, you will see a wet pipe with a puddle on the floor. Eventually the walls near this pipe will start showing signs of mould; plaster starts becoming powdery, paint peels off from the pipes and/or the wall - which turn a green colour - and water seeps through the wall underneath wall tiles.
Condensation affects other rooms too. Kitchens are especially vulnerable, as are bedrooms (if not ventilated) and any room in which clothes are hung to dry, particularly if they are hung over radiators to dry. You may notice in these rooms plasterboard becoming 'blown up', and chipboard starting to "rise".
Protecting your property from the effects of damp
All buildings must be allowed to breathe. This means ensuring rooms are well ventilated, have low moisture content and do not have moisture 'sealed in' to the walls courtesy of non-breathable surface coverings.
So, what action should you take? In the first instance, landlords and homeowners must be proactive in checking external walls for signs of damage. Regular checks and preventative / repair work should be carried out to keep brick faces and mortar free from penetrating moisture.
Inside the property, homeowners and tenants must take responsibility for controlling condensation. For example, in small rooms, radiator valves should be turned down and doors left open to keep the air from stagnating. Where possible, open a window or skylight to promote better movement of air around the rooms. You could also consider installing dehumidifiers in some of the worst affected rooms.
If the problem occurs in larger spaces, check if there is a window / skylight that has been left open or is not properly sealed. A continual supply of cold air could be interacting with the warm air created from the radiator and together they "stick" to the cold water pipes and surfaces in these rooms.
To deal with condensation problems in larger spaces, turn the radiator(s) in the rooms down to a minimum and fit lagging to the pipe. For our purposes, lagging a pipe means to wrap a pipe that conducts hot or cold water. The material is a rigid foam available from your local DIY store. It is tubular in shape and is scored across its length. The score opens up to a slit, which then allows you to insulate the pipe. This protects the pipe from coming into contact with air at different temperatures and with different moisture content.
No comments:
Post a Comment