Soil stack to male stub - double femal connector OK?

[Dunc]

I have a 110mm male stub sticking up through my slab from the rest bend under the slab (currently covered with a femal blanking cap). I need to connect the soil stack to this.

Is it OK to use a female/femal push-fit double socket (e.g. https://www.screwfix.com/p/floplast-push-fit-double-socket-pipe-coupler-black-110mm/47977) at the bottom of the stack? Just a little concerned about the stack contents falling the height of the house, hitting the male end with some force and escaping the rubber seal...but can't see another way of doing it?

(soil stack on the left - the other 2 are for sink & toilet which I guess will also have to be female/female connectors)

 

[Mr Punter]

I guess you could use solvent weld for the first fitting? https://www.screwfix.com/p/floplast-push-fit-solvent-weld-single-socket-pipe-coupler-grey-110mm/13738

[Oz07]

I don't understand what is being asked here. Are you asking if the force of the waste will squeeze itself between the pipe and the fitting then down to the rubber?! Ive forgot how neurotic you can be when doing a project. You get paralysed by decisions and worries like this. It won't be a problem. 

[ProDave]

If you study a female - female coupling when mated to the respective pipes, there is literally nothing for "passing material" to hit on it's way past.

[saveasteading]

9 hours ago, ProDave said:

nothing for "passing material" to hit on it's way past.

As long as the pipe is fully home. I've seen miscuts used that should have been done again.

The risk is when  the plummeting solids hit the bend at the bottom, forcing it downwards. But if that is properly bedded, again no issue.

11 hours ago, Oz07 said:

decisions and worries like this. It won't be a problem. 

It's good to understand the products  and to seek reassurance where necessary.

 

[Onoff]

To me the photos look like you already have a "double female" connector in place on each soil stub coming up. You can see there's a little internal stop that the pipe inserts as far as. In your case, more importantly it stops the connector slipping down.

 

 

Each appears to then be capped with one of these. These can be simple removed by getting a flat blade screwdriver under the lip and levering up. As an aside I always use a silicone spray or smear of silicone/plumbers grease when assembling this stuff:

 

 

[Onoff]

Random site but another option. Solvent weld one of these on the stub pipe:

 

[Oz07]

Stop indulging OPs worries we are here to reassure and dispel stress. We've all been in the trenches

[Dunc]

Thanks guys. I do appreciate the moral support (i.e. pull up your big boy pants and get on with it) @Oz07 😀

 

Having said that, the solvent weld option looks less risky. Inspection of the pushfit does show that the downstream male end will simply be in the center of the fitting against the small stop tab, but there is no lip so nothing but air pressure preventing contents sliding down the outside of the male pipe's chamfer.

 

Unless I'm mistaken, the caps that the groundworks guys left are a single piece. Will have another look at them though, thanks @Onoff

 

The bend at the bottom is under the MOT and slab so well beyond my ability to inspect it 20 times a day like I do with most of my other "worry-it-might-not-be-tight-enough" jobs 🤣

 

 

[Onoff]

28 minutes ago, Dunc said:

Unless I'm mistaken, the caps that the groundworks guys left are a single piece. Will have another look at them though, thanks @Onoff

 

 

I think you're mistaken 😂

[ProDave]

39 minutes ago, Dunc said:

Having said that, the solvent weld option looks less risky. Inspection of the pushfit does show that the downstream male end will simply be in the center of the fitting against the small stop tab, but there is no lip so nothing but air pressure preventing contents sliding down the outside of the male pipe's chamfer.

Solvent weld is good, BUT.  It can't be undone.  So make SURE before fitting the solvent weld coupling that you have the height right and you will never ever want to remove it again to adjust the height with respect to finished floor level.  AND make sure you use plenty of solvent weld adhesive and do it thoroughly.  Otherwise a poorly done joint that leaks cannot be undone to re do it.

 

If in doubt practice on some scrap pipe and fittings first.

[Oz07]

Id be steering well clear of solvent weld where passing thru a floor slap just put the pipe in and stop worrying 

[Onoff]

Yep, dry fit any solvent weld assembly first and put an alignment mark on adjoining fittings with a Sharpie. 

 

Slap on the solvent weld and as quick as you can fit together and align the marks. 

 

Nothing so complex needed here.