Those enamel steel sinks are cheap for a reason.
Enamel steel sinks have been popular for a long time in low-end construction as an “inexpensive” means of providing that “enamel” look without the higher cost of more durable enamel Cast Iron. If you work at it and take enough time, enamel cast iron sinks and tubs will scratch, chip and stain—-but not quite to the extent of enamel steel. These steel sinks and tubs are much more susceptible to impact damage and rapid corrosion because the metal is so thin. Cast iron sinks can have bare metal exposed for years and never rust through the way a steel sink will—and will be primarily a cosmetic concern.
Another very common issue with older style enamel steel sinks and tubs (of which there are many still in service) is that they have “welded overflows” in the case of the sinks, and “welded support bases” on the tubs. These welds tend to rust and corrode and in so doing pop off the enamel where the tub or sink can then rust through. In the case of the sinks, if the overflow rusts and corrodes, the sink will leak when the water gets high enough to run into the overflow.
In these first two pictures you can see where the spot welds have corroded and “popped” the enamel off the inside of the sink. While a largely cosmetic issue (in terms of leaking from the sink side) it can mean that the overflow itself under the sink will leak. It also represents issues with keeping the sink clean. Sinks like this are at the end of their life and should be replaced.
This next picture shows the rusting spot-welds on the underside—and the overflow did leak where it was rusted through.
Modern enamel steel sinks have plastic glue-on overflows and the tubs have foam-block supports to prevent this particular problem that occurs with the spot-welds. They will never, however be on an equal footing with Cast Iron—and still a cheap alternative.
Charles Buell, Seattle Home Inspector
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