Saturday, 23rd January 2010
Now that the ice has melted on the area’s roads you will have noticed the massive increase in the number of potholes. The problem is caused by water entering through minor defects in the surface of the tarmac, expanding as it freezes and de-laminating the surface.
The bad news for homeowners is that there are many areas of your property which may also have been affected by the recent prolonged spell of sub-zero temperatures.
- Cracks to render - in a similar way to how frost affects the surface of the road water will work its way in to hairline render cracks and collect between the render and the brickwork behind. As the water freezes and expands the render is forced away from the wall loosing its key. This is a particular problem with rendered plinths.
- Roofing tiles - over time the water resistant surface to a clay tile weathers and begins to soak up water. This is fine while the normal wetting/drying process continues but if the temperature drops below zero while the tile is wet the expanding water causes the surface of the tile to delaminate.
- Brickwork - just like weathered clay tiles some bricks absorb moisture. These will normally be the softer red bricks which are often found in the oversailing courses of chimneys on period properties or for decoration at the corners of the main walls.
- Guttering joints - as the rubber seal at the joint of polythene guttering weathers a layer of moisture will often form around it. TAs the moisture freezes the seal is forced further up allowing more water in below until the joint fails and starts to drip, saturating the brickwork below (see number 3).
All of these defects can lead to more serious problems if left unattended so I would recommend a quick check around your property this week end.
Author: Justin Burns