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 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.
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 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 of copper pipe and fitting method of repairing a burst lead pipe is to cut out repair coupling. Making the affected length and replace it with a new length temporary repair to lead pipe of pipe; this job is best left to an expert plumber. 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.