Bath/Basin waste correct route - outside or in?

[TwoBrowndogs]

Can you please help me with correct and least problematic pipe runs for bath and basin waste. Two options me thinks.

So, issues are that I’m trying to avoid putting a hole in floorboards to sing a trap. Using a 50mm seal, the outlet can’t sling under the centre length of bath as pipe is restricted by horizontal bath support strut. I thought I could use a 25mm extension to lower trap to clear strut but only 20 mm clear of floor - unless I use a shallow trap … but not really allowed.

I could use a dry valve (McAlpine selfclose or osma hepVO) under bath (but I had issues with one before - long hair keeping valve open) with a knuckle joint that should clear strut and swept Tee into basin waste sand out wall further down

Wasn’t sure if teeing the basin and sink into same run is a good idea or not.

1 – simply route the bath waste direct outside ensuring that connection to SVP is greater than 200mm below WC. The run will be about 265cm of nice shiny black solvent. Gives me least bends but not the prettiest to the rest of the world. Run basin out separate above WC.

2 – Find a way of running bath waste under bath tee into basin. Will look neater outside but more bends inside and of course a tee. Option 3 is a neater version but still need to sling waste under bath

What would you guys do please .. I’m not looking for fastest install but the “right” thing.

Thanks lots, Paul

 

[Nige F]

Can the bath tap end be reversed - next to basin ( probably not I guess) Shorter waste run

 

[blup]

My experience of option 2 (the bath) is that blockages form because the bend is so close to the waste.

Blup

 

[Hugh Jaleak]

I'm looking at option 2, turn the bath waste so it heads to the outside wall, (but runs internally), dog leg it to take it under the floor before it emerges from behind the bath, pick up basin and then go through the wall? Fit a rodding eye where it emerges through the wall to allow cleaning when required, and use bends as opposed to elbows, to allow smoother flow, and put an anti vac trap on the basin.

Bear in mind black pipe will fade over time, white is more resistant to the sunlight in my experience.

 

[TwoBrowndogs]

Thanks Nige F, no I can't flip the bath .. else the wife would flip

Blup, Hugh, thanks .. I was able to keep a 50mm seal trap (and stay with regs) and was able to drop it a little on a 25mm extender so the pipe now runs central under bath (can slide a 1 mm spacer under the trap .. phew) I couldn't easily run near external wall as other pipework there. So as you say, a dog leg on the horizontal , swept bend (and create a rodding eye, basin down on another swept T and straight out the wall to another swept T and rodding point into SVP. Will look neater outside and one less hole to core cut too and all accessible above floor.

Get what you say Hugh about the black. I used some push fit (had to) and that's now grey .. the black Osma solvent is a fresh as it was (after three years on south face) .. surprised me too. This is in shade out the way so even better.

Thanks for your help folks. Really helps when you can bounce ideas.

 

[TwoBrowndogs]

Um, I've hit a snag .. well an over sight .. or cock up .. all same result anyway

Inside is fine and couldn't place the holes anywhere other than where I did. I'd hopped I'd just run the 40mm pipe straight into stack .. only I'd clean forgot about the 200mm Zone WC input. So ensuring I don't bring the 40mm in to the zone means the fall is significant (about 140mm in 0.8m. Also means I can't connect to stack as the angle is to much for the strap boss.

I'm wondering if I can replace the 90deg branch with a 135 (or 45 deg depending how you look at them), it would be lower giving me a chance to add strap a boss just above. I notice that Osma do a 76deg with boss (maybe that boss would line up), but the 135 does not have boss (got to be a reason for that).

Am I allowed to put 135 in but that would always give a to greater fall but here would be about 350mm from exit building to stack? Any thought . .apart from "muppet".

Thanks

 

[John D v2.0]

Last i checked there's no maximum fall for a wc branch, it's only the smaller unventilated ones that need it. So you could do as you suggest.

 

[dilalio]

Why not just put the 90° elbow that comes out the wall, for the bath at the 7 o clock position, run a bit of 40mm to a 135 and then boss onto the stack at a lower position

 

[John D v2.0]

That picture is golden!

Why not just put the 90° elbow that comes out the wall, for the bath at the 7 o clock position, run a bit of 40mm to a 135 and then boss onto the stack at a lower position

I think that would be too much fall for an unventilated 40mm branch which could be an issue for the basin when emptying the bath, although it's a good point that with an aav or similar there would be no issue.

 

[dilalio]

I meant it in conjunction with an antivac trap and a T coming out the wall with a rodding eye pointing back into the wall... standard works really.

 

[Hugh Jaleak]

No comment on the picture.

Would say the AAV needs to go higher, should be above the spillover level of the highest appliance, in this case, the basin. I also trust there is a vented stack elsewhere on the drainage run?

 

[dilalio]

I had to d/load an App on my phone and draw it freehand with my finger on the screen, whilst in the pub watching F1.

I tried 4 times to stop it looking phallic then thought ferk it

 

[TwoBrowndogs]

Thanks folks, especially to ditalio for the superb picture. I did say you could call me a muppet .. but not sure about *ick Now my wife thinks that diy.com is a porn site . Now way that is accidental .. I missed F1 .. was it that bad ?

That's not an AAV you see just a cap/cage balanced on top. The SVP is at the start of a run of 4 houses. I have an external AAV for another room down the line but as this is the start it will be extended above roof line with that cage (in line with building control request).

I didn't really want to put any bend in the 40mm (although than option I guess) and there will be a rod point from right side (on already in bathroom).

The whole fall of the WC branch was (I thought) not related to un-vented/vented but rather making sure water carries solids etc .. although for a very short run (as it exits to vertical stack) I guess a 45/135 would be better anyway .. just wasn't sure if allowed.

 

[dilalio]

A 135 in the 40mm will look fine, believe me... It won't look like a dick

Far better to do that and also perhaps kick it out away from the wall with another couple of m&f 135's so that you can meet the centre of the 4" boss without angle-ing it away from the wall and clips... Hard to explain but harder to draw

 

[dilalio]

Delete: double post due to some server laziness perhaps!