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Tuesday, 28 January 2014

Damp appearing?

In this sort of weather you might find damp in places that were dry before. Why?

Well, when you have driving rain rather than just rain it tends to get into cracks and holes that it might otherwise miss. Key areas that are at risk are:

1. Silicone seals around doors and windows - the sealant fails over time and comes away from the wall or frame, this then allows water to get driven in behind. When the wall gets wet it transmits heat better and so it gets colder. The cold patch then attracts condensation, this then leads to mould formation etc. Builders and DIY'ers are quite notorious for choosing the cheapest / most obvious option. These silicons are the most likely to fail, because basically they are rubbish. Look for a more elastic silicon and one that will adhere for longer. They will all eventually fail, but putting more time between replacement is just easier.

2. Poor pointing - pointing is really important for keeping out driving rain. It can fail in a number of ways. Firstly it can be re-pointed using the wrong mortar. Using cement on old solid walls is fundamentally wrong. It traps water in and also ruins the softer brick / stone. Always use a lime mortar (preferably lime putty with stone dust). Rake out to a depth that is double the height, get it wet first and then press the mortar well into the joints. Pointing should be flush with the bricks / stone.

3. Cracks in render - in a similar vein to the pointing, render on older buildings should be lime based not cement. Again wind driven rain gets into the thinnest cracks and gets stuck behind the cement render. Ideally any cement render should be removed, but at the very least cracks should be repaired to stop the water ingress.

4. Leaky gutters - I see no end of leaky gutters at this time of the year. This is because we use poor quality, narrow plastic guttering, downpipes and fixings. The ideal is to use the correctly sized metal guttering (like Lindab), but at the very least make sure that your guttering is not leaking and draining correctly. Water flowing over walls and behind fascias is asking for trouble.

The main message is MAINTENANCE. Whatever you have on your house just make sure that it is working as well as it can. Then, if possible, look for more permanent solutions in the Spring / Summer when the rain stops!!!!! Lime, especially is easier to apply when it is drier and warmer, so good lime contractors are at a premium during this time, so get in quick.