Soil pipe to roof

13 Dec 2005
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United Kingdom

I've had someone do some work and it involved moving the toilet and soil pipe. Before they did anything, the soil pipe was connected to another pipe that went to the roof. Now the soil pipe comes out the toilet, through the roof (extension) and then into the ground. I was told that the soil pipe no longer needs to be connected to the pipe that goes to the roof.

Is this right?

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Depends.. Are there other wastes connected to the soil pipe below the toilet on that level. Like a basin or shower? I'm assuming this is on first floor. The pipe should have been raised above the branch forming a stubstack terminating to a dirgo above what we call flood level the height of the highest overflow on that level. Strictly speaking only one stack from a drain needs to be ventilated to air/roof. If you make a direct connection which sounds like what you may have you can create suction on the drain and ultimately it can block up//water level rise in toilet not nice experience when you turd doesn't go away!!
If they've turned it into essential what's called a stub stack, which it sounds like, then the WC can be a max of roughly 1.5M above the bend in the stack underground. I think it's 2m max to a sink if it's above that level on the same stack. That's if it is connected directly into the ventilated drain /sewer system. As Mr B says though, it should have a pipe running upwards above the overflow level of the highest appliance and have a auto air vent (durgo) installed.

If it's above those levels then it should feed into normal ventilated soil stack.
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It would seem like they need to sort it out.

The toilet is on the first floor, the pipe comes out the back and through the outside wall into the loft space in the extension.

The shower, bath, sink and condensation pipe from the boiler connect to the toilet waste pipe and runs along the loft space about 3 meters then drops straight down about 2-2.5 meters into the ground, what used to be the outside toilet.

There is no air vent connected. The air vent ATM is just an open pipe going to the roof on the outside of the house and from what you've said, it looks like that's what needs to be connected up to the main waste pipe in the loft space like it was before the toilet was moved.
What has happened to the original soil pipe that went up to the roof to vent? The regs ask for the highest point of the drain to be vented to atmosphere, although the WC and ancillaries have been moved to join to the former downstairs WC connection, this may have left the drains without satisfactory venting arrangements which in itself, could cause problems.

Personally I think it sounds like a bodge, but without looking at it, its difficult to determine. Has the Building Control Officer inspected the work and passed the drainage side of things?
It probably was a bodge that they thought I wouldn't notice. I've told them to fix it, which they will be doing.
Handymen...they've done a bit of everything and the closer I've looked at what they've done the more things I see that need to be re-done. Their time working here ended yesterday.

A costly mistake!

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