There are several different methods for fixing old or damaged pipes. If a pipe has just sprung a simple leak, then a plumber can come and repair it without too much trouble. This process usually involves inserting a pipe about one size smaller into the original and applying expanding urethane foam crack filler in the space between the two pipes. However, if the pipe is either too old or worn-out, then it may need to be replaced. The most common cause of busted pipes is freezing water. When water freezes inside of your pipes it expands. Since pipes are not built to be flexible, repeated expansion and contraction will weaken the integrity of pipes and eventually, they will have to be replaced.