Water supply piping connection: copper to galvanize (C) Daniel FriedmanCast Iron Drain Piping Identification, Diagnosis, Repair

  • CAST IRON DRAIN PIPING- CONTENTS: Cast iron drain pipes in buildings. Diagnose & repairing cast iron drain connection & leak problems. Diagnosesewer gas odors traced to cast iron drain deterioration. Types of leaks occurring in cast iron drain piping. Life expectancy of cast iron drain piping.
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Cast iron plumbing drain piping:

This article lists our in-depth articles on inspecting, testing, and repairing problems with cast iron building plumbing drain waste vent piping, piping materials, clogged or noisy pipes, and types of pipe hazards or product defects. The articles at this website will answer most questions about water supply & drain piping of all materials and types.

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Cast Iron Building Drain Piping: Identification, Diagnosis, Repair

Cast iron pipe cleanout (C) Daniel Friedman Pipe leak repair methods

Cast iron drain piping has been used in buildings for more than 100 years and can last for 50 years or longer. T

his heavy material is available in diameters from 2" and up, with typical main building drains of 4" to 6" in diameter in residential buildings. A hub system connects pipe sections, originally using melted lead to seal the joint against wastewater leaks or sewer gas odor leaks.

The cast iron pipe hub and stub were wiped with oil to remove water, avoiding a dangerous steam flash when lead was poured into the fitting. Most modern cast iron connections are made using rubber or plastic fittings that no longer require heating and melting lead.

The illustrations (left) show accessing a cast iron drain cleanout and two methods of emergency, temporary repair of leaks in drain piping.

Making New Drain Connections to Old Cast Iron Drain Piping

Our photograph of cast iron drain piping (below left) demonstrates two methods by which connections have been made to newer copper drain lines. At upper left a black plastic hub fitting has been used to connect the 4" copper drain to the cast iron drain line.

Cast iron pipe cleanout (C) Daniel Friedman Cast iron drain connections (C) Daniel Friedman

At center-right in the above left photo a questionable clamp-on type fitting has been used for the same purpose, including a makeshift clamp using a block of wood to accommodate use of the wrong-sized clamp around the cast iron drain. Stains on the upper section of piping indicate that this drain system has been leaking.

Our photograph at above right shows three clamp-on connectors joining cast iron and plastic drains to the cast iron sewer line.

Cast Iron Drain Piping Leak & Odor Locations, Causes, Diagnosis

Our photograph (below left) shows an odd double-hub connection on a vertical section of cast iron drain piping in a 1935-built home in poughkeepsie, NY. You can see by the rust stains that this cast iron pipe joint has been leaking for some time, that the concrete "repair" action was not fully effective, and that the basement is exposed to unsanitary conditions due to sewage leakage.

Our second cast iron drain leak photograph (below right) shows a different type of drain pipe leak: sewer gases. This fitting and collection of galvanized iron elbows and nipples should be removed and the opening in the vertical cast iron drain plugged to stop potentially dangerous sewer gases from entering the building.

We suspect that this drain was once used to receive water from a basement dehumidifier or water softener, but it is no longer in use. The dry "trap" formed at the bottom of the piping "U" no longer serves to keep sewer gases out of the building.

Watch out: sewer gases may be both unsanitary and also risk of a very serious methane gas explosion. See SEWER GAS ODORS.

Cast iron drain leak (C) Daniel Friedman Cast iron drain leak (C) Daniel Friedman

Several types of leaks occur in Cast Iron Piping:

Galvanized plumbing drain (C) Daniel Friedman

Our photograph shows that the rope trying to secure the galvanized drain line to the cast iron sewer piping confirm a history of leak troubles and improper plumbing connections.

Cast Iron Drain Pipe Leak & Repair Case - Odors Lead to Discovery of Under-Floor Drain Leaks

New York City Storm Drain Overflow (C) Daniel Friedman

Cast Iron Drains Receiving Roof Gutter Drainage May Burst Basement Floor Slabs

Often on city lots that are flat and poorly drained, builders or building owners were pressed to decide how to get rid of rainwater spilling off of building roofs and through the gutter and downspout system.

The best approach is to route these drains to a nearby city storm drain, pumping if necessary but best by gravity. This avoids overloading the city sewer system during periods of heavy rainfall.

Our photograph above shows a New York City storm drain overflow station (officially, a: New York State Wet Weather Discharge Point) where excess drainage is dumped into the Hudson River when more water or wastewater enters the city sewer system than can be handled. The green sign atop this drain warns

If you see a discharge during dry weather, please call 311 - DEP (Department of Environmental Protection).

Overloading a city's sewer often means that raw sewage is simply overflowed or dumped into local rivers or streams.

In building gutter drains (C) Daniel Friedman

But It was common in previous generations for builders to rout (usually cast iron) drain pipes from ground-level outside of a building into the building, under the basement floor slab, and out to the municipal sewer system. These drains were used to receive roof gutter drainage and dispose of it into the city sewers.

Our photo (left) shows an in-basement cast iron drain line that originally received outside gutter/downspout drain water. At the time of our inspection that system had been changed and downspouts were routed to above-ground drains (unfortunately still too close to the building to assure a dry basement).

A problem with the in-building, under-floor piping disposal of roof runoff, besides overloading the city sewers in wet weather, is that eventually the under-floor drain may become clogged, perhaps with leaves washing into the drain from the building's gutters. The best result of that problem is that the drain stops draining and gutters spill outdoors along the foundation, perhaps leading to basement water entry, rot, mold, and insect damage.

Still more troubling, a blocked under-floor drain in a building left with no heat sometimes led to frozen drain pipes and burst, heaved piping and floor damage in the building, followed by an in-building flood when freezing weather changed to a thaw.

If you have roof gutters connected to drains that enter the building and are routed to the sewers, (a step still permitted and even required in a few communities), reconnecting the drains from outside ground-level to a nearby storm drain may be a better approach.

Tracking Down Leaky Cast Iron Drain Pipes Under a Floor Slab that Sent Sewer Gases into Transite (Asbestos Cement) HVAC Ducts

Details of this sewer gas odor case, cast iron drain leak, and repair are at CAST IRON DRAIN LEAK, ODOR, REPAIR. Excerpts are below.

A reader (Conrad) provided us with the photographs and case history of the successful track-down of sewer gas odors in a building (SEWER GAS ODORS). The case began with a complaint of sewer gas odors in the building's heating duct work system.

Details about the case illustrated just below, including more pictures and notes on how the building owner tracked the sewer smell to the basement floor slab (and transite heating ducts in the slab) can be read at CAST IRON DRAIN LEAK, ODOR, REPAIR.

Sewer odor and cast iron drain (C) Daniel Friedman Sewer odor and cast iron drain (C) Daniel Friedman

SLAB DUCTWORK - catalogs the functional and environmental problems found when HVAC air ducts are routed in or below floor slabs.

Drain Piping Articles


Continue reading at CAST IRON DRAIN LEAK, ODOR, REPAIR or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Other types of building piping systems are discussed beginning at PIPING in BUILDINGS, CLOGS, LEAKS, TYPES

Or see DRAIN & SEWER PIPING - home

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CAST IRON DRAIN PIPING at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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