SUSTAINABILITY How to prevent burst pipes in cold weather


Protect your home from burst pipes

In the home
Andy Wilson

Many parts of Mayo experienced record low temperatures during December, with minus 17 degrees being recorded at Straide and temperatures as low as minus 13 on the coast. At the Claremorris weather station, the average temperature for the whole month was around minus one degree.
In such circumstances, it is no surprise that many people have suffered the inconvenience of burst pipes. The advice given by insurance companies in relation to freezing weather is given mainly with a view to reducing the incidence of insurance claims, and is not necessarily always in the best interests of householders.
One nugget of wisdom received from an insurance company advises leaving your loft hatch open on cold nights, in order to warm up the loft space! Of course, there are far better ways to keep your loft pipes safe, that don’t involve losing all the heat from your house in the process.
Get someone who is competent with electrical wiring to fit a lamp holder and switch in the loft space, with the lamp holder situated in the same part of the loft as the pipes. On cold nights, simply turn on the light. Better still, have it activated automatically by a thermostat set a degree or two above freezing point. Some thermostats are designed to be plugged into ordinary three-pin sockets.
The downside of this method is that it doesn’t work too well where there are long pipe runs in a loft, and it doesn’t work at all when pipes are routed down the roof under the slates (as often is the case with dormer bungalows). One recently built house in which I carried out remedial work lately had five separate pipes, all scantily lagged, running down under the slates. Some of the pipes were in physical contact with the slates. Hardly surprising then, that the pipes freeze during cold weather.
The same house also had bare copper pipes running to radiators through a vented, unheated crawl space. Whoever designed, built and signed off that particularly house should seriously consider going back to night school! Unfortunately, this sort of thing is all too common.

There is one rule of thumb about lagging pipes – and that’s do it right. Firstly, use the correct size of lagging for the pipe concerned. Plumbers’ suppliers sell lagging for every pipe size up from half inch, in quarter-inch increments, and it’s very cheap.
Secondly, every last bit of the pipe should be lagged. It’s pretty pointless just doing the bits that are easy to reach. Pay particularly attention to joints, where wider diameter lagging may be needed. Bare copper pipe conducts heat over 1,000 times faster than lagged pipe, so even small areas of bare pipe can lead to localised freezing.
Thirdly, the lagging should be taped in place at regular intervals, especially round bends in the pipe. Duct tape works reasonably well, provided it is wrapped back on to itself and is pressed down firmly. Economy-sized rolls can be bought in most builders’ providers.
Fourthly, add a second and even a third layer of lagging over the first layer. Usually with secondary lagging it is necessary to go one half inch larger with the lagging diameter. Hence, put one-and-a-quarter-inch lagging over three-quarter-inch lagging, and inch lagging over half-inch.
With secondary lagging, its better to have tight fitting lagging that doesn’t quite go all the way round than over-sized lagging that hangs loose. Overlap the joins in the previous layer and tape securely in place. In really cold places (such as down under the slates of dormers, if this can be accessed) use a third layer as well. At only €1 or so a length, this could be the best €50 or €100 you ever spend!

Next article Heating and hot water systems

Andy Wilson
works part-time as a domestic energy consultant. He can be contacted at 087 6714075 or