Internal rest bends

[Ppocketwatch]

Hi, 

I'm a first-time self builder currently at groundworks stage. My home has two internal rest bends, one will be within a solid floor (foam glass insulation below limecrete slab) and the other will be in the void under a suspended timber floor. 

My architect said that having internal soil pipes + rest bends is standard on modern houses - my previous house was an old cottage and this was external. But now I'm at the point of building the drainage system, it's dawned on me how inaccessible both of these bends will be. 

 

Is this normal/acceptable?

Are there any steps I should take to increase accessibility to these rest bends?

 

I know that damage is unlikely, but if either do crack and leak with age it'll 1) take me a long time to work out where the smell/fluid is coming from 2) be expensive and extremely bothersome to dig the internal floor up to replace them.

 

All advice welcomed, as simple as possible please as I'm new to this!

[ProDave]

Personally I would not combine the utility and bathroom run, instead I would have a separate run straight out from the utility room and an extra IC along the top as shown in this plan.

 

 

[saveasteading]

I prefer to get the pipes out by the shortest runs , and with minimum complexity.

That makes more pipework outside in your case, but reduces risk.

It often results in the outside drains starting higher so the outside trenching isn't so deep.

So your utility drain would go straight out, perhaps combined with the bath , and your wc another line by the direct route.

 

I see a note for a wc next to the bath, but don't see what it is for.

[ToughButterCup]

1 hour ago, Ppocketwatch said:

..

My architect said that having internal soil pipes + rest bends is standard on modern houses - my previous house was an old cottage and this was external. But now I'm at the point of building the drainage system, it's dawned on me how inaccessible both of these bends will be. 

 

Is this normal/acceptable?

...

 

Yes. Yes.

 

I had the same 'jangle' that you are having. And to a lesser extent that feeling remains.

 

Its almost as if keeping foul drainage inside the house rather than getting rid of it out of the house as fast as possible is 'wrong' . I still feel a small 'is-that-necessary-wince' every time I hear the passage of foul drainage inside the house.  And that 5 years after the piping was successfully  pressure - tested.

 

And it still hasn't leaked

[Super_Paulie]

I've got an internal rest bend that would be pretty much impossible to get to without major surgery. Frankly I haven't given it a second thought, works just fine. I guess you/I could rod it from the nearest outlet, which I have as a dishwasher just above the rest. Can't see how it would ever crack to be honest.

[Ppocketwatch]

2 hours ago, ProDave said:

Personally I would not combine the utility and bathroom run, instead I would have a separate run straight out from the utility room and an extra IC along the top as shown in this plan.

 

 

I did consider this, and yes it would be preferable, but there is a thick limecrete foundation cap (which is already built) that the pipe would need to run through in order to be at the required gradient. So this design is a work-around that involves no adjustment to the foundation which I'm hoping will still work!

 

[Ppocketwatch]

2 hours ago, saveasteading said:

I see a note for a wc next to the bath, but don't see what it is for.

I think the note is just poorly placed, and is referring to the toilet opposite the bath.

[saveasteading]

My logic is that other things go wrong.

Eg one toilet in my house sometimes doesn't clear. It needs a shove and all is well again until another time.

I suspect it is over use of TP and not a scientific thing.

On one job a long drain blocked when the occupier moved in. The drain had never been used officially. It turned out to be a sanitary product in mid run. It had run out of speed. Then it affects subsequent use.

ie low use can cause issues too.

A neighbour had 'stuff' appearing in a downstairs wc from the one above. Was all according to regs.

 

Ie other things go wrong and I'd rather it was outside and simple.

But do it to regs and it will mostly work and always be roddable.

[Ppocketwatch]

54 minutes ago, Super_Paulie said:

I've got an internal rest bend that would be pretty much impossible to get to without major surgery. Frankly I haven't given it a second thought, works just fine. I guess you/I could rod it from the nearest outlet, which I have as a dishwasher just above the rest. Can't see how it would ever crack to be honest.

Yeah it's not the rodding that concerns me, just that the plastic or rubber seal may degrade in a few decades and I'll have no reasonable way of getting to it. 

[Oz07]

22 minutes ago, Ppocketwatch said:

Yeah it's not the rodding that concerns me, just that the plastic or rubber seal may degrade in a few decades and I'll have no reasonable way of getting to it. 

I think they would line it internally but its not a bad point. 

[Nickfromwales]

Just after levelling the ‘wet plant’ room, I took this pic of my current clients build. 
 

 

You can see the access coupler 100mm or so above FFL. This offers rodding access from there to the IC with complete ease. 
 

41 minutes ago, Ppocketwatch said:

Yeah it's not the rodding that concerns me, just that the plastic or rubber seal may degrade in a few decades and I'll have no reasonable way of getting to it. 

Not going to happen. You are fine to ‘chill out’. 

[Super_Paulie]

8 hours ago, Ppocketwatch said:

Yeah it's not the rodding that concerns me, just that the plastic or rubber seal may degrade in a few decades and I'll have no reasonable way of getting to it. 

 

Your rest bend will have the rubber seal on the inside with the stack as the male section going into it. Even if it did degrade you'll still be totally fine I'm sure. 👍🏻