(Photo from Gloucester City News)
Recently the UK suddenly went from a freakishly mild autumn to cold hard winter. The pipe that takes condensation away from our boiler freezes when we have a hard freeze. The boiler realizes it can’t get rid of its condensate, so it stops working. Don’t get me started about whoever installed the boiler (before we got the house) and the idiocy of running that pipe down an exterior wall when it could easily have been protected.
Usually I’m the one who disconnects a coupling and inserts a diverter to allow condensate to drip into a bucket. This time my wife did it. It’s a bit of a hassle. Someday we’ll get around to putting in a nicer solution.
When we installed an exterior faucet (outside tap) for the garden hose, I couldn’t find a freeze-proof one in the UK that I liked. They tended to have washers that we would need to replace regularly. I wanted a quarter turn ball valve that should operate for years before it needs maintenance. I had one shipped from the States. The threading is incompatible with UK garden hoses, but we put an American quick-connect fitting on it. That is compatible.
When we shut off that hose, the valve is inside the house, in a cupboard under a sink. The pipe from there to the outside drains. It won’t burst in a hard freeze because there is no water in it to turn to ice and expand.
The rest of our water pipes are no more vulnerable than in any other modern-build British house. If you are not one of my British readers, I should explain what that means. We must keep the house from getting too cold. Although we could turn off the water supply and drain most of the water lines, there is no draindown (bleed) valve at the lowest point. Some of our pipes would still contain water. The radiators for our heating system also contain water. We need to not let the house get cold enough for those to freeze.
Maybe houses up in Scotland are better prepared for bitter cold, but in northern England where we are, we aren’t accustomed to such temperatures very often. I’ve seen evidence that winters used to be colder where we live. At the “Victorian village” near Ironbridge, part of the exhibit is a boat that used to be used as an icebreaker on the canals. We rarely get a thin skin of ice along the edges of canals now.
You don’t need to know more details about how our houses are built. The water pipe issues I mentioned are common in climates where winter temperatures don’t get too damned cold too often for too long.
In southeast Texas where I grew up, plumbing is more vulnerable than where I live in the UK. The supply pipe often comes up outside the house, bare, and then goes in through a wall. Much of the supply pipe is in the attic. Builders don’t bother to insulate it. If you want to put some insulation on it, you have to climb up there and do it yourself. Insulation will get the pipes through a mild freeze.
Insulation isn’t enough for a hard freeze like the one that is due to arrive tomorrow.
Houses are built differently in the northern USA. You wouldn’t have to worry about water pipes freezing if you live in Chicago or Minneapolis or Denver, unless you left the place without any heating turned on. Water pipes tend to be kept toward the middle of houses there. They aren’t run through exterior walls like they are in southeast Texas or in England. Of course, that means you can’t gaze out the window while washing the dishes, but your pipes are in the warmest parts of the house in winter.
If you live in a climate mild enough to have water pipes that are vulnerable in a hard freeze, plenty of people will offer silly ideas about how to protect them during an arctic blast. They’ll tell you to leave faucets dripping overnight. That’s a bad idea. For one thing, if you go to bed before your neighbors, when they set their faucets to drip, that may reduce water pressure in the area enough to make your dripping stop. For another thing, if everyone does this and a fire starts, the firefighters may not be able to get enough water pressure to fight the fire.
Other people may tell you to insulate your pipes and then just hope for the best. Insulating the pipes helps, but as I said, there is a limit to how much of a freeze it can fend off.
It’s better to remember some of the physics you learned in school. Water expands when it freezes. It expands so much that if it freezes in your pipes, it can rupture the pipes. Then when everything thaws, you’ll have water leaks.
When it’s a really hard freeze, it’s better to set aside an emergency supply of drinking water, then shut off the water supply and drain your pipes as much as you can. But there is something you should do before you drain the lines.
Turn off your hot water heater. Sometimes draining the lines starts a siphon effect that can partially empty the hot water tank. If any of the heating element becomes no longer immersed in water and turns on, the heating element will melt and be ruined.
Many Southern houses have a cutoff valve where the pipe comes out of the ground to go into the house. Smart homeowners have that changed to a cutoff-and-draindown valve, as close to ground level as possible. If you have a cutoff valve like that, it’s fine to use it instead of going to the meter box and using a special tool to turn off your water there.
Whether or not you have a draindown valve, after the water supply is shut off, go around the house and open all the water valves. All of them! You need to let air into the pipes to replace the water that runs out. You don’t want a closed valve to cause a vacuum lock that prevents some water from draining.
When that is finished, you may want to cover your cutoff valve to protect it from freezing. Only an inch or two of pipe may be exposed there, but it needs protection of its own. If you don’t have anything else to cover it, a towel and some plastic (to keep the towel dry) will do. For that matter, at houses with ordinary exterior faucets, sometimes I’ve used a towel, a plastic trash bag and some duct tape to get through a moderate freeze.
When you turn the water on again, turn on the supply and then go around the house turning off faucets. If you turn off the faucets first, when you turn on the water supply, it can create an “air hammer” effect that could damage plumbing. In my early twenties I learned the hard way that I should have thought about this. It blew a joint in my pipes.
It's all basic physics from school. Use it well and you can avoid a gosh-awful mess when the freeze passes and everything thaws.