Help! - Holes Below Ground Level in Cast Stack (Pictures)

[carlo789]

Hi,

I have recently bought a c.1900 house which I am quickly finding out is being held up by the paint and wallpaper it came with.

The survey (as you might expect!) highlighted numerous instances of damp in the property, and my first job is to tackle the sources of the damp.

In doing so, I noticed a damp patch around the base of the cast iron soil stack and picked away at the concrete surround (which duly fell away) to reveal 2 rusty holes in the stack on opposite sides. The stack goes into a cylindrical (clay?) pot which is much larger than the pipe. The pipe sits above a pipe / hole of the same diameter. Now all the loose concrete has been removed, if kick the stack, it will kind of vibrate, suggesting it’s hovering above the clay pot.

The clay pot(?) goes down about by 4cm from the floor. The holes in the pipe are about 2cm below floor level.
My questions on this are:

1) Should the stack be hovering above the clay fitting or has it corroded completely, freeing itself in the process?
2) Should I try to repair or just replace with plastic?
3) If I repair, how would I do this? ( I have heard of people replacing upper sections with plastic, but not lower sections?).

Thanks in advance all!

Untitled

• carlo789
• 29 Sep 2012
• 1

Untitled

• carlo789
• 29 Sep 2012
• 1

Untitled

• carlo789
• 29 Sep 2012
• 1

 

[DAZB]

The pipe at one point will have been socketed into the clay and the perimeter sealed with mortar etc but over time it has corroded. You could cover the actual holes it has made either with a slip of slate or similar and re-mortar it back flush or simpy replace the entire run with plastic. I would favour the plastic myself.

 

[carlo789]

Thanks DAZB... Would it be normal / ok to say replace the lower 50cm with plastic, apart from the fact it'd look naff?

 

[Hugh Jaleak]

It can be done, but the important issue is that cast in extremely heavy. If you are confident the fixings above will hold the remainder firmly in place, then cutting out the bottom section is perfectly feasible. A McAlpine DC-1 coupling will slot into the clay pipe, taking you to 110mm plastic, then a 'Fernco' coupling will swap from plastic to cast. (Although wont look too pretty...)

If you aren't confident on the fixings holding up the cast then I would seriously consider replacing it. A section of the stack falling could easily kill anyone who happened to be in the wrong place at the wrong time. If the base is rotten, then possible other areas of the stack may be wearing thin. For the sake of about £100 to DIY, replace it and forget it.

 

[calorific]

Totally agree with Hugh. Get as much done in plastic as possible

 

[carlo789]

Hi,

Thanks both. . . I think I had seen estimates of £700+ for replacing the pipe (mine will be difficult as it's internal at the ground floor and external at 1st floor loo height to about 6 - 7m from ground level - hence, probably some crazy scaffolding arrangment).

I think though, I might have to play it safe and pay up?

 

[Armo74]

Plastic all the way. Fit it then forget about it. Maintanance free and a lot easier than cast to add on the extra waste outlets

 

[calorific]

It's still cheaper than having to dig down and underpin and/or replace a load of rotten bricks, wood etc if you don;t get it fixed properly soon

 

[Hugh Jaleak]

My concern would be if the bottom is that rotten, then the rest may not be far behind.... Replacing bits may prove a false economy, thats assuming the whole lot doesnt fracture or collapse when you try and cut a piece out..... May well find the 'ears' are nailed into wooden plugs hammered into the brickwork joints. These will be holding up with a wing and a prayer by now I would imagine!

To be perfectly honest for peace of mind i'd replace it all. It's then secure, watertight and cannot fall and do any damage. (Also proves a lot easier if you want to replace the bathroom suite, especially the pan as modern pans often have the outlet at a lower height than the cast soil pipe exiting throught the wall.....) Lastly, breaks underground are often used as a convenient entrance/exit by rats.....