Cracked Cast Iron Drain Pipe

[dstone54]

My wife and I bought the old family homeplace about two years ago. The house was built in 1937. One of the upstairs bathrooms has a cast iron drain pipe that drains the water from the sink, commode and tub to the plumbing under the house. The cast iron pipe is cracked from under the house up into the house somewhere(the home inspector discovered this when he was crawling under the house during the home inspection). Is anyone aware of any plumbers that work on older homes and can run a drain pipe liner or sleeve through the cast iron pipe or some similar type approach. The alternative is tearing up the bathroom floor upstairs, the wall downstairs and the floor downstairs to replace the pipe. Any suggestions would be greatly appreciated. Thanks

[HayZee518]

as far as I know there is no sleeve that'll go into the CI pipe. the cracked pipe needs to be cut out and a new one or pvc plastic is put in place with fernco rubber couplings. I'm sure Lazypup - our resident plumber, will tell you.

[LazyPup]

There are a number of different techniques currently being used by municipal sanitation departments to install an impervious liner on the interior wall of old sewer lines. The reasoning is that while the liners may provide less than a permanent repair the offset is that they can be installed without the cost of long term disruption of municipal traffic flows or buried utilities such as natural gas, electrical mains, steam headers, or buried telephone and cable communications lines. As a general rule the techniques are only indicated for lines of 6" diameter or greater although there have recently been some efforts to use the methods for 3" and 4" residential sewer lines. (By definition- a residential sewer line is the buried line from the structure to the septic tank or municipal sewer main).

dstone54's question involves a leak in a cast iron stack.

While one might think the leak is the problem generally a leak in a stack is only the tip of the iceburg and is in fact indicative of much more serious problems.

As a rule cast iron pipe is extremely strong, resistant to corrosion or the acids present in a waste line and is may be considered as nearly permanent however it does have one serious drawback. Cast iron is brittle and when acted upon by severe external forces it may crack or shatter. Often we take advantage of this fact when removing cast iron by simply using a pair of 5lb hammers to shatter that pipes into smaller more managable pieces.

When cast iron stacks are installed they are basically self-supporting however we also install metal strap hangers or wooden blocking & bracing to help support the stack.

In the case of the stack in question the house is 70 years old and it is highly likely that the original metal strapping has rusted away or more likely that the house has settled over the years rendering the wooden blocking or hangers ineffective. In many instances the as the house settles the original blocking may ultimately be repositioned to a point where it is now in fact causing severe mechanical strain on the cast iron pipe. The initial crack on the pipe temporarily releives the strain but if left unchecked it could result in the line shattering. Cast iron pipe is very heavy and if a section were to shatter it would instantly result in all the pipe above it falling down, often pulling lateral lines out of the walls and causing a major disasster.

The proper method of repairing the leak would be to locate the damaged section of pipe and replace it with PVC in the manner that was described by Hayzee above.

The good news is that you should be able to acess the pipes without cutting into the floors.

You should be able to access all the pipes and make any necessary repairs to the pipes on the ground floor from the crawlspace under the house.

For the second floor you begin by locating the position of the stack and make an opening in the wall and ceiling from the room below. Generally you will only need to make an opening one stud bay wide and perhaps one joist bay in the ceiling. This can later be easily repaired with sheet rock.