Any soil pipe experts?

[Pecanfan]

I've got a rather complicated soil pipe run to install and I'm at a bit of a loss as to whether what I'm trying to do will even be possible. A picture's worth a thousand words etc. etc. so here you go:-

first problem is that as soon as the soil pipe leaves the building through a 2ft thick brick wall, it needs to turn 90 degrees and head towards the soil stack. Can I even put a 90 degree access bend directly against the brickwork like this, or will it cause the adjoining soil pipe to be too far away from the wall to attach the supporting clips?

Secondly, I'd like (if possible) to run my sink waste into this soil pipe, to avoid the need for a second waste pipe to weave it's way around the w/c etc. By my understanding this means I'll need some form of horizontal T connector directly attaching to the pan. I'd then run a standard section of soil pipe to the right of this, along to the sink, with a screw-on end cap for access. The sink would just have a single vertical waste drop (hidden behind the pedestal) and attach to the soil pipe with a 40mm strap boss.

Can you actually get a T pan connector that would allow this? I assume public lavatories must have something like this, allowing several w/c's to connect to the same horizontal soil run?

Thirdly, I gather the stub stack can just be attached via a 92.5 degree access branch turned on it's side?

Anyway, some pointers and guidance would be greatly appreciated!

TIA,

Andy

[Set Square]

Can't you build the bend slightly *into* the brickwork - as long as you can still get at the rodding point access cover ok?

Does the soil pipe *need* to extend along to the basin? Can't you bring a smaller pipe along, and connect it into the large pipe near the pan?

A good source of inspiration may be to visit the toilets in a few of your local supermarkets. They seem to use exposed soilpipes with all sorts of things connected into them. May well give you some ideas!

[Dave]

See the following url for the bldg regs view (beware line splits:

'd always thought that a basin, shower, etc could only terminate in the soil stack but from re-reading the regs this isn't as clear as I thought previously.

[John Rumm]

won't need the air admitance valve on your new section.

I did this recently and found that the end of the elbow (or tee) needed to start inside the wall to get the turn in the right place so that the external pipe run can be clipped correctly.

You can get WC pan connectors designed to do exactly this:-

Thirdly, I gather the stub stack can just be attached via a 92.5 degree

Yup - there is enough give to allow a 90 degree angle if required.

[Pecanfan]

Potentially, but I've never seen a soil pipe end-cap with a 40mm waste hole built into it. That means I'd have to do the strap boss thing, which means the waste from the sink would have to meander along to the soil pipe *above* the level of the soil pipe (in order to drop into it). It's OK, shortly after posting I found this which should do the job nicely...

:-)

Andy

[The Natural Philosopher]

I have. Lots. Big rubber bung with a 1/34" hole in it.

Oh. Never seen that particular combination meself Neat.

My plumbers solved this one by drilling into the vertical soil pipe and glueing waste 'collars' into it so bath and basin feed in the side of it and bog in the top.

[Pecanfan]

Unfortunately it's about 8m away. :-(

Thought that might be the case - seems reasonable. Do you know roughly what size hole that requires? Presumably 130mm or so?

perfectly. Ta!

Cool - all problems solved. T'interweb's great. :-)

Cheers all!

Andy

[Set Square]

Yes, that's the sort of thing I had in mind.

[John Rumm]

Sounds about right, or maybe a tad more... I was fitting through an exterior rendered stud wall (which is a pain to make holes through because it starts out with mortar, then expanded metal lath, then ply, then foam, the plasterboard - try finding a drill bit to go through that!)

I held the end of the elbow against the wall and drew round it. Used a chisel on the SDS to cut round the outside of the line, tin snipped through the lath, then used a 5" hole saw on the ply and the plasterboard and foam. I actually found the 5" hole in the ply was still a little too small and needed to attack it with a reciprocating saw. So I would guess a 6" hole would see you clear. It does not need to be that size all the way through BTW, because the elbow will only penetrate a couple of inches into the wall.

[Pecanfan]

Sounds like fun! Well, I need to get through approximately 2ft of the hardest brick in the world so I'm going to look into hiring some form of diamond core drill - just to add to the fun I'll be 20ft up a ladder in gale force winds at the time - woohoo!! :-|

Andy

[John Rumm]

If using a core drill, why not drill from the inside out?

I have done a 4" core with 11" solid walls... that was easy to do by sticking a pilot hole right through and then drilling half way in from each side... the second one I did it was not as easy to get to the outside, so I did that all from the inside and just broke out the core when I ran out of depth on the core drill. You will need a powerful drill for a core much bigger than 4", my 780W Makita SDS only just coped with that.

In think in your case I would be tempted to core bore a hole big enough for the pipe (say 120mm), and then open out the final couple of inches a bit wider to accept the elbow using a SDS chisel, rather than make the whole length of the hole bigger than you need just so the coller of the elbow will fit one end.

[Pecanfan]

'cause a) I'm nervous about the last bits of brick etc. hitting our downstair's neighbour's window, which is directly under the hole and b) I need to core a slightly bigger hole on the outside to take the lip of the access bend.

Think I've got the same drill as you - HR2450? Great piece of kit - definitely my best buy last year :-). So far, this year's best buy is a £4 angle grinder from ScrewFix - £4 'a tells ya!!! Anyway, not planning on abusing my drill with this job - I think the local hire shop do a proper core drill with bits for £20 or so.

Yeah - I'll either be doing that or, if possible, I'll use two separate core drills - using the larger from outside to cut a 1-2" rebate into the brickwork as mentioned.

Andy

[Set Square]

You *really* don't want to be operating a core drill when 20' up a ladder! You wouldn't be *allowed* to do it on H&S grounds if you were being employed rather than d.i.y-ing. You really ought to be doing it from the inside - even if that means having someone else on the ladder to catch any large bits of brick when you break through.

[John Rumm]

I tend to find there is no real breakout with a core drill - a large lump of core should stay put in the end of the bit.

Even if you do that you will still need to attack with a chisel to break it away from the wall since it wont be going all the way through...

Yup, that is the beastie, and very nice it is too ;-)

It is not so much a power issue (it has no trouble swinging the bit), but unless you drill dead straight you find yourself right on the limit of the torque limiter, which can make it difficult to get the bit spinning at all. (back out a little and then use light pressure as you ease back toward the coal face!). In some respects if you were going to use the drill up a ladder then I would feel relatively safe with that one since when it does snag, the clutch does a very good job of insulating you from any kick.

[Zikki Malambo]

If the 8M leads directly to the soil stack, I still cant see the nead for the stub stack & AAV. However, if you feel this is a must have, then i'd recommend taking a smaller dia pipe up to loft level (Assuming you own all the floors above you:=)) and then fitting the AAV there. However, as long as the stack is vented, I don't see it being needed.

[Pecanfan]

It was building regs who suggested the AAV on a 1m stub stack so I took it as read really (don't know if it makes a difference, but the 8m is via 3 90 degree bends!). Hadn't thought of running it all the way up to the loft - good idea! How would that work then? Could I just put a strap boss on the soil pipe to the left of the toilet and run 40mm to the loft? If so, can you get AAVs that fit to 40mm pipe? That would certainly be much more practical.

Cheers!

Andy