Soil Stack Damage - Help

karlitob

Hi all

I think either my cast iron soil stack; or the pvc connection that the toilet feeds into it from may be damaged. The problem is I can’t see it - the join is buried in a flat roof; the down pipe is buried behind a built in dresser; and the pvc pipe from the toilet which is outside is buried in external insulation.

There is a leak and at this stage I’m nearly certain it is either the pipe itself or the connection, and I’m leaning to the connection.

Obviously the dresser and the insulation can be removed; and the concrete flat roof can be exposed also if needs be.

But I’m wondering would a camera down the jacks be able to confidently diagnose the fault before any hacking. If so, any recommendations and general ball park cost.

Appreciate any other comments also. Thanks.

karlitob

karlitob wrote: »

Hi all

I think either my cast iron soil stack; or the pvc connection that the toilet feeds into it from may be damaged. The problem is I can’t see it - the join is buried in a flat roof; the down pipe is buried behind a built in dresser; and the pvc pipe from the toilet which is outside is buried in external insulation.

There is a leak and at this stage I’m nearly certain it is either the pipe itself or the connection, and I’m leaning to the connection.

Obviously the dresser and the insulation can be removed; and the concrete flat roof can be exposed also if needs be.

But I’m wondering would a camera down the jacks be able to confidently diagnose the fault before any hacking. If so, any recommendations and general ball park cost.

Appreciate any other comments also. Thanks.

Appreciate any advice or guidance on this. Thanks

K.Flyer

A camera down the pipe might pick up where a poor connection is, but not a guarantee.
If you know the route of the pipe I would consider making a small opening near the stain and using a camera scope pushed through examine the outside of the pipe. Its the method I use and it's usually quite successful as you can pick up where the water is dripping from.

karlitob

K.Flyer wrote: »

A camera down the pipe might pick up where a poor connection is, but not a guarantee.
If you know the route of the pipe I would consider making a small opening near the stain and using a camera scope pushed through examine the outside of the pipe. Its the method I use and it's usually quite successful as you can pick up where the water is dripping from.

Thanks for that. It’s a good idea.

The problem is the pipe and connection is buried in either concrete on the flat roof or external insulation. I think it has seeped or is sopping so I’m worried that I still wouldn’t be able to find the source using a camera that way. Maybe I have to just take out the external insulation first and have a look.

Since this problem started a few months after we first moved in - I think connections may have been affected as two pieces of steel were installed at either side of the soil stack.

Before we buried the soil pipe above the flat roof in external insulation - I did manage to take a picture. To me, it looks wet around the area of old roof flashing and could possibly be getting in there.

I know it’s hard to make out from the photo. The problem is behind bottom right; but the connection is to the left.

K.Flyer

That looks very strange the way they left it, why didn't they come out far enough to completely cover the pipe?

It looks to me that you are going to have to remove the insulation, clean and dry out the area.
Then re- seal around where the pipe goes through the slab and rebuild the insulation but this time step it out far enough to fully encompass the down pipe with a slight slope on the ledge for water run off.
Then seal the point where the pipe enters the insulation.

karlitob

K.Flyer wrote: »

That looks very strange the way they left it, why didn't they come out far enough to completely cover the pipe?

It looks to me that you are going to have to remove the insulation, clean and dry out the area.
Then re- seal around where the pipe goes through the slab and rebuild the insulation but this time step it out far enough to fully encompass the down pipe with a slight slope on the ledge for water run off.
Then seal the point where the pipe enters the insulation.

Yeah - it’s a funny set up.

That pipe is PVC and is attached to the cast iron soil stack at a 45degree to bring it away from the newly installed external insulation at the time. So that left an alcove behind the cast iron section of the soil stack where the old pipe went into the flat roof. As we had problems elsewhere we all thought it was cold bridging. We reasoned that if the soil stack was leaking there’d be foul smell and worse water damage.

The pipe has been sealed where it enters (last year - no change).

There is a slope on the ledge but I think it needs something like a proper drip edge.


Thanks for your help. Yeah - I’ll just have to remove it. I do have access from underneath - I might see about hiring a camera and see what I can see.

karlitob

So - pulled out the external insulation and had a look.

There’s a cast iron y connection from the toilet to the soil stack.

There’s a rubber connection with a jubilee clip on the toilet pvc pipe, which goes over the cast iron pipe and it’s as dry as a bone. Problem not there.

The air vent was put in by the external insulation guys as they had to bring out the vent beyond the external insulation. The air vent (female connection) goes over the cast iron spigot. It’s tough to get into so it was joined by silicone around the outside (though he couldn’t get into the back) and by expanding foam insulation from the inside. I thought that the problem was here - toilet flushes, some sort of whirlpool action where the water hits the y connection and splashes come up and down the side of the poor connection and in through the roof through sub standard flashing. After drying the area and flushing the toilet there was a little trickle of water. However when I took off the vent pipe and cleaned the whole area and flushed the toilet again, no water at all. It’s fine.

So it doesn’t seem as though above the flat roof is the problem. I now have better access for a camera to get through.

The pipe from underneath is still wet. Access is hard and I can feel the bottom bell section of the y section.

Is the bottom of the y section actually a spigot (male) and fits into another bell (female) or is the bottom of the y a bell (male) and the spigot (the Down pipe flowing away actually a male). Finding it hard to find the anatomy online.

Any comments or guidance welcome.

Calahonda52

First up get a multi wick for reconnecting the vent pipe to the cast iron stub, forget about silicone, expanding foam.

It may not look as neat as the black pipe but neatness is already gone

If you have the tools I would cut it flush at the spigot, give you more room for what follows below

Second, Given that the original cast iron designs had molten lead poured into the joints, my guess is that the Y goes into a spigot.

Is it possible that the Y is cracked at the V joint?

If you can, say with a wire brush on a flexi on a drill clean off as much crap as you can, and then dry it with a heat gun, you could think about trying to line the inside of the pipe with fibre glass mesh and isopan from the motor factors, or what ever they call it now.

PS make sure nothing drops down the pipe unless you have good access below

karlitob

Calahonda52 wrote: »

First up get a multi wick for reconnecting the vent pipe to the cast iron stub, forget about silicone, expanding foam.

It may not look as neat as the black pipe but neatness is already gone

If you have the tools I would cut it flush at the spigot, give you more room for what follows below

Second, Given that the original cast iron designs had molten lead poured into the joints, my guess is that the Y goes into a spigot.

Is it possible that the Y is cracked at the V joint?

If you can, say with a wire brush on a flexi on a drill clean off as much crap as you can, and then dry it with a heat gun, you could think about trying to line the inside of the pipe with fibre glass mesh and isopan from the motor factors, or what ever they call it now.

PS make sure nothing drops down the pipe unless you have good access below

Thanks so much for that. I think you’re right. I think it’s cracked somewhere around the v of the y connection.

Hadn’t thought about lining the pipe. Might be beyond my diy skills - seems a bit far down. Might investigate getting it done by a professional. It seems like it should do the trick. Hope it’s not crazy expensive.

Thanks again.

karlitob

Update;

The only leak that I could find was where the pvc vent pipe was connected to the cast iron spigot at 45 degrees to bring the vent pipe away from the house so as to fit in the external insulation. The insulators put the pvc connector *over* the spigot and siliconed the outside (though they doubly get in at the back) and put spray foam on the inside (cos they couldn’t get at the back.

My working hypothesis is that some how, the rush of toilet water when it hit the v of the y connection was sucked up a little to where the spigot and pvc connector of the vent pipe connected and a little bit of water leaked out each time we flushed the jacks.

Since I took off the pvc connector last week, the cast iron pipe section that i can access on the ground floor is dry.

Sound plausible?