If the plumbing system in your home is not adequately protected, severe weather can cause water to freeze in the pipes, producing blockages and burst pipes. You can deal with these yourself, but it is better to prevent any damage by checking your anti-frost defences every autumn.
Frost protection is built into the structure of a well-designed, modern home and some of the important design points have already been referred to briefly.
SERVICE PIPE This pipe conveys water from the water authority’s communication pipe to the house and should be covered by at least 750mm of earth throughout its length. If it enters the house by a hollow, boarded floor, it should be thoroughly protected from draughts. The pipe should be taken up into the roof space – to supply the cold water storage cistern – against an internal wall.
STORAGE CISTERN The cold water storage cistern is best situated against a flue which is in constant use.
To prevent icy draughts blowing up the warning pipe leading from the cistern, you can fit a hinged copper flap over the outlet; there is, however, a risk that this will jam in the open or closed position. A better method is to extend the pipe within the cistern and bend it over so its outlet is about 38mm Oiin below the surface of the water. There are gadgets, such as the frostguard, which make it easy to extend internally the warning pipe from a storage or flushing cistern.
The boiler, hot water storage cylinder and cold water storage cistern are best installed in a vertical column so the vulnerable cold water cistern receives the benefit of the rising warm air.
All lengths of water pipe within the roof space should be kept short and well away from the eaves.
LAGGING Efficient lagging of storage tanks and pipes reduces the rate at which water loses its warmth and protects pipes exposed to cold air; but it cannot make up for a bad plumbing design and it will not add heat to the system.
Pipes to lag are those against external walls, under the ground floor and in the roof space. Don’t omit the vent pipe of the hot water system since the water in this pipe is not as hot as that in the rest of the system and, if it freezes, it can create a vacuum which could damage the cylinder.
There are several types of pipe lagging available and it is best to use inorganic materials. These include wrap-round glass fibre; moulded polystyrene and flexible moulded foam plastic. Polystyrene is rather awkward to use, but is good for underground pipes since it does not absorb water. The moulded types of lagging come in a variety of sizes to fit different pipes, so make sure you buy the appropriate size.
Whichever type you use, make sure you lag behind pipes against external walls to protect them from the cold wall. Cover the tails of ball valves and all but the handles of stopcocks and gate valves; if you are using rigid lagging sections, you will need some of the wrap-round type for these areas.
Bind wrap-round insulation round the pipe like a bandage, overlapping it to prevent gaps, and secure it with string or adhesive tape. Where a pipe joins a cistern, make a full turn and tie it to hold the end in place. When joining two lengths overlap them and tie securely.
Secure moulded sections with plastic adhesive tape, starting at the cistern. Where the sections join along a length of pipe, seal the joint with tape. Open up flexible moulding along one side, slip it round the pipe and seal the opening with adhesive tape, taking particular care at any elbows. If you lag the pipes before fitting them, there is of course no need to slit the lagging; you can slide the pipe length through it. Where pipes go through a wall, make sure the insulation goes right up to the wall.
You also need to protect the cold water cistern. The easiest way to cover a square cistern is to use expanded polystyrene slabs. For a circular cistern use glass fibre tank wrap. If you have insulating material between the floor joists in the loft, make sure the area immediately below the tank is left uncovered so warm air is allowed to reach the tank.
DEALING WITH FROZEN PIPES
If. in spite of your precautions, a freeze-up does occur, it is essential to deal with it immediately. If there is any delay the plug of ice will spread along the pipe and increase the risk of damage.
You can gauge the position of the freeze-up from the situation of the plumbing fittings which have stopped working. If, for instance, water is not flowing into the main cold water storage cistern but is running from the cold tap over the kitchen sink, the plug of ice must be in the rising main between the branch to the kitchen sink and the cistern.
Strip off the lagging from the affected pipe and apply heat – either with cloths soaked in hot water and wrung dry or a filled hot water bottle. If a pipe is inaccessible, direct a jet of warm air towards it from a hair dryer or the outlet of a vacuum cleaner. Fortunately modern copper tubing conducts very well and a small plug of ice can often be melted by applying heat to the pipe about a metre from the actual location of the ice.
BURST PIPE IF the freeze-up results in a burst pipe the first indication will probably be water dripping through a ceiling, since pipes in the loft are most likely to burst; wherever the leak, immediate action is vital. Turn off the main stopcock and open up every tap in the house. This will drain the cistern and pipes and reduce the damage. When the system is completely drained, find the position of the leak. DAMAGED COPPER PIPING If you have copper piping, you will probably find a compression or soldered capillary joint will have been forced open by the expansion of ice. All you need to do in this case is fit a new joint. Copper piping does sometimes split under pressure. If that happens, you will have to cut out the defective length and insert a new length. An easy way of doing this is to insert a repair coupling.
Cut out the damaged section of pipe with a fine tooth hacksaw, leaving a gap of not more than 89mm between the pipe ends. Remove the burr from the tube ends with a small file. One end of the coupling has a tube stop, the other is free to 3c slide along the pipe. Slacken the nuts of the coupling, spring one end of the pipe out just enough to allow you to slide the repair coupling over it. Line it up with the other pipe end and push the coupling on to it until the tube stop is reached. Unscrew the nuts and slide them and the copper jointing rings along the pipe. Apply jointing compound or gloss paint into the bevels of the fitting and around the leading edge of the jointing rings. Tighten the nuts with a spanner so the tube is lightly gripped: make another turn, or a turn and a quarter, making sure you do not overtighten.
BURST LEAD PIPE The orthodox and approved method of repairing a burst lead pipe is to cut out the affected length and replace it with a new length of pipe; this job is best left to an expert. You can, however, make a temporary repair with one of the epoxy resin repair kits available. Dry the affected length of pipe thoroughly and knock the edges of the split together with a hammer. Rub down with abrasive paper. Make up the resin filler according to the manufacturer’s instructions and apply it round the pipe to cover the split and the surrounding area. While the filler is still plastic. bind round it with a glass fibre bandage and ‘butter’ a further layer of resin filler over the bandage. When thoroughly set, rub down with abrasive paper to make an unobtrusive joint. You will be able to use the pipe again within a few hours.