Filling in old bog pipe

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Shrinkage of the concrete as it cures might make your fill a loose plug which could possibly sink at some time, taking a section of tiling with it.

It might be worth cutting a trench around the top (possibly 2 to 3" deep and creating a circular slab with steel reinforcing sitting on solid floor at its outer edges.

Cic.

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I was worried about that too - and lack of adhesion to a smooth plastic pipe. That was my thinking in throwing the concrete round the bend (rather than plug the pipe with expanding foam first) - the concrete will be curved and should lock in place.

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The other solution to that could be to drill some holes through the pipe sides near the top, plug and stick in some stainless steel screws or resin bond some short lengths of stud to provide an anchor. Wonder if it is necessary...

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loose plug

tiling with

We had a salt glazed pipe under our kitchen at the last house that had previously served a downstairs loo. I just packed it with crumpled newspaper and filled it with a very strong sharpe sand and cement plug maybe 9" long. Never had any problems with it in the 25 years we were there

AWEM

Filling with concrete is all I have ever seen done whilst on site.

Mind you that is all that British Coal did with their mine shafts and they only put a few feet of concrete at the top of a long vertical hole.

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I think it's almost bound to be 'loose' because of the shrinkage but only by about 2mm maximum at a guess. I think that it's also very likely to slip down by about the same amount even with the curve but only time will tell if it shows up badly (or at all) on the tiles.

If you're not in a hurry to tile you could do as you originally intended and see what happens; if it does slip you can either skim over or if it's bad you would still be able to follow my suggestion and do a belt and braces job.

Cic.

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All other comments notwithstanding, I think I'll whack 4 bits of stud through the side into the existing floor. Only takes a few minutes and the resin (which I keep around as it's so damn useful) will set in the time it takes me to mix a batch of concrete.

I hadn't factored in shrinkage, but with such a smooth bore pipe, it has little to hold on to. Salt glaze (which is what I was expecting) would have been better - cement sticks to that to some extent.

So I'm very glad you brought it up :)

Especially as it might well have a piano wheel right on top (we plan to put it there) and that's no light weight (another thread coming up)...

Cheers

Tim

I'd say this was the more elegant solution. Possibly even easier would be to cut a *square* recess and embed a decent paving stone over the pipe (As you all seem to have giant angle grinders here, that would probably be easier than cement too.)

Are you sure that the pipe will not move under the weight of the concrete? Just how well is it supported?

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Probably by sod all apart from earth under it ;->

The studs go though and into the floor slab around the pipe...

In article , Tim Watts writes

Me neither, thankfully, but last time I did it I obtained a plastic cap (available off the shelf) which is a tight fit over the end of the pipe. If you were able to excavate around the pipe enough to cut it so that when the cap is fitted, it is flush to the floor, you could tile straight on to that. The cap is plenty strong enough.

That would also not put the pipe beyond re-use in the future.

Had exactly the same situation and the BCO told me to do exactly that.

That would be my prefered approach as well. Even if the pipe is not going to be used again a 2' vertical drop and swept bend full of concrete would not be fun to have to dig out. I'd find some way of plugging the pipe firmly a few inches below the top and then use a concret plug. Maybe two rings of screws out into the floor slab. The lower ring having a bit of thick bit of tight fitting card board shoved against them. It would hold long enough for the concrete to set with the second ring of screws holding that in place one the dryish mixture was set.

Same here - fistfuls of newspaper to stop it entering the main system, and tamped strong concrete mix on top of that.

Polystyrene packaging works well, but I think you can get something called a "mushroom bung" if you're serious

I'll be interested in replies. Next door had their outside loo removed by cowboys and my guess is this is how they sealed it off. And it hasn't worked - we get drain smells. Of course I can't be certain this is the reason. Theirs would likely have been ceramic, due to the age.

I'd be surprised if a minor air leak (if there is) outside would be discernable by you? IME you have to have a fairly open pipe in a confined space to get a decent whiff.

Anyway...

That bit went OK. I got 3 M10 SS studs resined into the existing floor, nespaper bung down the bottom round the bend. Filled with strong C20-ish concrete.

Had some left, so decided to bung up the defunct entries into the old manhole. Fine so far. Wondered where the 3rd port went. Guessed it might be a ground floor flat roof gutter. Yes, that seemed to be so, except that downpipe is blocked to all but the smallest trickle so the water is going into the ground. Luckily that bit of the house is a sticky out bit with a deep (2' rather than the rest of the house which is 1') foundation concrete strip sitting directly on clay - so washout is likely minimal from a leaking downpipe and the roof is 3m2 so not too much water.

So that's on the semi urgent list of jobs for conversion to a soakaway.

So after that, I thought I'd better check I hadn't let any concrete related debris get into the main drains (I was careful). Went round the various manholes flushing with a hose from the previous one. All well and good until I got to the last one before the road.

At this point, it is a 6" shared private sewer for 3-4 houses and I must maintain my section at my expense.

It didn't look too happy. It's an old style one with a u-trap and bypass port. The bypass plug has never been there, but despite that, there was water backing up the main exit pipe. Not my concrete, that much I was certain.

So, in the spirit of DIY, got a 3m bit of JG speedfit and plugged the hose on the end and tried a bit of low pressure jetting. Could get more than 1.5m down the main exit. Something soft and sqidgey down there.

So, now, in the spirit of knowing when to give up, called out the local rodding guys, who came within the hour and ran a jet down it. That worked.

As I had to pay for the hour, he offered to jet the entire 6" up the garden too. This was a good thing. Although it was functioning, there were piles of clag (mostly paper and some tree roots) upsteam that came down. They then blocked the main outlet again - so something's not right down there.

So he cleared that again - this time, something that looked like a cloth came out which was obviously the culprit - although we both concluded that there must be a snag in the pipe for it to be getting caught on.

He went through again and could get to the main sewer, but said something didn't feel right. Maybe roots.

So I've booked a CCTV survey for next week. It's not urgent as the darin is running, but might as well deal with it in an orderly manner now it's come to light.

Two bits of good news:

2) I start a new job tomorrow so can actually afford all this bollocks. Glad I caught it before the drain overflowed and got gross. At least it's working for now. Also glad I chopped down most of the trees over the drain run (bah).

Ho hum...

Interesting - I got 30m of drain replaced fully by the house insurance.

Rob

Oooh... Then it would be certainly worth a call to mine, before starting work... Never even occurred to me that such things might be covered....

I'll go ahead with the CCTV survey which gives me a report I could send them.