QOD for 6/12/06 plumbing

Hi to all,

Here’s todays question



Hi to all,

The correct answer is: ***Corrosion from the inside

****Iron and steel pipes rust from the inside, with horizontal piping deteriorating faster than vertical pipes. the image in the question is of a cast drain that is 100 years old and rusted to the point of colapse.



100 years – not bad

Wonder how many years we can get out of pvc??

BTW something that will speed things up DRAIN CLEANER


Hi Richard,

I agree the stuff does last pretty well.

This was an interesting one, the cast was on grade which always makes me take a closer look, and this one had a big gob of mortar on it that looked out of place, sure enough it had been to “repair” the waste pipe. That piece and I suspect many others will turn to dust when touched.

The point in posting that picture and this question was to make members aware that sometomes something that looks OK at first glance may actually be in very poor shape.

I recommend tapping on older cast drains they sound hollow when very rusty.

No one wants to end up liable for replacing that stuff, this was on a very large property and the replacement cost of those drains will be in the thousands.



And yes before anyone calls me on it I know they are suposed to be hollow but you all know what I mean :mrgreen:


Good eve Gerry

I did a very good Navy type of patch on one in my home when I moved in – problem patch was perfict — pipe was compleatly clogged – a real big mess followed

10-4 on looking a little deeper -


At 100 years old the entire system should be replaced as it is passed its life expectancy, IMHO.:slight_smile:

Excellent questions Gerry, very much appreciated.:smiley:

Here’s a link from the Canadian Research Council on “Failures in Gray Cast Iron Distribution Pipes.” From the 60’s to present, ductile iron was used in the mfg of cast iron pipes.


Great site thanks Aurelio
Much appreciated

Roy Cooke

Looks like most of those answers would apply according to the NRC site.

Good link Aruelio