Soil pipe - rodding point or vent?

[News]

We have a soil pipe running down the outside of the house, which goes underground then turns horizontal, and runs towards the main sewer. A few feet from the soil pipe is a branch which leaves the underground pipe at 45 degrees, and pokes out of the garden about 10 or 12 inches. Completely open. I have assumed it to be a rodding point with the push on cap long gone, so was planning to buy a replacement. However, could it be a vent point, in which case blocking it may cause problems? How would I know?

[charles]

which way does the 45° go?

[Tim+]

Does it matter? Surely the only reason to use a 45 degree pipe that comes to the surface is to provide rodding access. All the vents I've seen have been vertical. It needs a cover of some sort anyway, if only to stop rocks and things falling down it. I would fit a sealing cap and see if that causes problems with water getting sucked out of the U-bends (indicating that it has a venting function). If that happens I'm sure that it could be converted to a vented cap with some large drill holes.

Tim

[charles]

It might have been for a garden "privy" and the person who removed it didn't kno waht to do with the pipe?

[News]

The 45 points towards the main sewer, so is an acute angle towards the soil pipe i.e. rods would go towards the sewer.

Which seems a perfectly logical answer, and what was already at the back of my mind.

Absolutely no trace of an old garden privy. The soil pipe serves two en suite bathrooms upstairs that were installed 30 - 35 years ago, so that is when the rodding/vent point was installed.

Thanks!

[News]

In message , Phil L writes

Exactly. I did look, and the soil pipe is indeed capped with a vent, so Plan A is to just accept the other is a rodding point, and cap it. Should that cause problems (which I doubt), then Plan B is to drill a few ventilation holes in the new cap.

[News]

In message , Phil L writes

Yes indeed - but venting it is Plan B, only to be used if capping causes a problem, which seems unlikely, given that the soil pipe is vented.

[News]

In message , Phil L writes

Quite right - I mean a cage. The idiotic pigeons try to nest on the chimney pots, along with the rooks, jays etc. I think one must have fallen down an unused chimney a while ago - sounds of movement behind a wall where there was a fireplace, years ago. Breaks my heart to think about all the fireplaces some heathen ripped out of this house, years ago.