Latest Discussions : Plumbing


04:18PM | 09/14/04
Member Since: 09/13/04
2 lifetime posts
I maintain a 75 year old apartment building with cast iron drain pipes.

The four inch lines still work well and I haven't had a problem with them in the 15 years that I've owned the building.

The 1.5 and 2 inch lines that haven't been replaced are badly restricted or even broken. I have been replacing the worst of these pipes with ABS pipes attached with no-hubs to the existing system.

The questions:

1. If a pipe appears to be solid (I'm not sure how you make that judgment when the pipe is behind a wall) how effective would pressure washing the pipes be? The buildup on the inside of the pipes is a semi-solid brownish material. I have been able to clear it out partially with a round wire brush attached to a drill over short distances but only with considerable effort. Is a pressure washer effective against this kind of buildup? Is running a pressure washer something that should definitely be done by a professional plumber or would renting one be an option?

2. Are there any chemicals that are effective against this kind of buildup? Would you recommend some kind of periodic application of chemicals as a form of preventative maintenance?

3. I have been using a sawzall and a grinder to gut through the old cast iron pipes. I have recently become aware of a tool designed to "snap" cast iron pipe. The tool is expensive and I probably won't buy one but I am curious. How well do these things work? Can they work in tight spaces (the crawl space under my building is less than two feet).


06:52PM | 09/16/04
I've been thinking about your post the past few days. I've not heard of cast iron pipes smaller than 2". And at some point you are going to have to replace the 2" and probably the four inch also. You can have your pipes video cameraed to learn about their insides.

1. I am not experience in power washing. I do know that I have to use a wood chisel and hammer to cut the residue out of cast iron. Also that debri can blow loose and hang up shutting the whole system down.

2. I am also not chemically aware and while there are chemicals against roots and bacteria you need to have your line cleaned out first.

3. There are snap cast iron cutters that are like a big set of scissors. You can rent them from a rental store. They require about four feet to open the arms. There are also rachet cutters that have a pointed chain that goes around the pipe and one arm that rachets the chain tighter until it snaps the pipe. However both of these methods can crush old pipe instead of snapping it. A grinder with a diamond or tile saw blade seems to be a popular cutting method.

You could also try a good sink cleaning machine starting with a small pointed blade and then going up to a larger bit until you get the lines open. Of course it could only be the rust holding the pipe together and when you clean the line they may begin leaking where before they just won't drain very well.

If it was my building I would see what a well exprienced drain cleaner could do and plan on having to replace the pipes at some point.

Jim D

01:48AM | 09/17/04
Member Since: 01/06/01
342 lifetime posts
Davefoc - hi, I've seen the civil engineers on military bases use chemicals in the closed-water systems for hot water radiator heating. They'd come in during the fall and open the system at some location, bleed off some water, input the chemicals, and let it circulate several days. Then, they'd go to each radiator location and bleed out any air, then bleed out the gunky water until it ran clean. The whole process could take a couple weeks. They did this twice in the three years I was assigned to the base I observed it at. I don't know what the chemicals were, but it did help get the hot water circulating to all of the radiators.

I'm not sure if the pipe system you're dealing with is for a hot water radiator system or not. I' sorry that I can't give you any better information than this. Good luck! Jim D/West Point, VA


03:31AM | 09/17/04
Member Since: 09/13/04
2 lifetime posts
Thank you for your replies.

LonnythePlumber was right about the 1.5 inch cast iron. The 1.5 inch pipes in my building are galvanized.

As to the chemicals Jim D., these pipes are drain pipes and I was asking about whether any of the various drain cleaning chemicals out there were effective. My experience with these is not good. I see them used by tenants in an attempt to clear a drain and mostly they just make the miserable job of snaking a drain a little more miserable as far as I can see. I was hoping though that there might be some simple chemical approach that would actually be effective.

As an aside the ABS drain pipes and fittings in the building have been nearly flawless. There are 30 year old ABS pipes in the building that are in perfect condition. It is difficult to understand from my perspective why cast iron continues to be used in some new construction today.


05:29PM | 09/17/04
The plastic makes much more noise than cast iron. This is primarily noticed in walls where the upper floors drain vertically to lower floors. Also the fumes from PVC can kill you before a fire does. We were concerned about plastics strength and it was limited to only three floor structures but that limitation has recently been eliminated.

Cast iron was required between fire walls but now it's back to plastic with a fire caulking that shuts off the pipe and thus air from one room to another.

erik peterson

07:19AM | 09/18/04
Member Since: 06/23/03
223 lifetime posts
11/2" c.i. is very common in older buildings..."power-jetting" may help clear some of the rust/debris in the lines. If your going to keep the building i would suggest replacing the smaller lines increasing to 2". check your local codes as some authorities do not allow a.b.s. on commercial buildings.


04:23AM | 09/20/04
I did not realize there was 1 1/2" cast iron pipe. But there certainly is and I'm pleased that Eric motivated me to check it out.


03:34PM | 06/09/17 this will take care the old buildup in your cast iron pipes

Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.

Reply choose button


Post new button or Login button