How to run this drain pipe?

[Vernonv]

Hi All,
I'm after some advice/options on the easiest and/or best way to do the following:

We are looking at putting in a hand basin in the toilet and I will need to run the drain pipe to the exterior brick wall (see diagram). The floor is concrete slab.

Here are some of the options I can see:

1. Along the outside face of the internal stud wall and then through the brick. Easy option, but not the most aesthetically pleasing.

2. Down through the slab and then under and towards the outside - I'm not exactly sure how this could be achieved (i.e. drilling, digging, cutting a slot in the slab??).

3. Run the drain pipe through the inside of the internal cavity wall. Not sure if this will be possible or advisable - it's not a load bearing wall .

Advice and comment most welcome.

[seriph1]

All achievable options but as you say, some less appealing than others. Other options used by ppl with solid walls/floors is to create a 'box' that runs along the Wall to the outside wall. This can be very attractive and provide additional storage and shelf space etc. Something often lacking in these spaces. if you're willing to go to the trouble, you could cut a section of the plaster out of the wall and then run your waste through the studs using a hole saw, but you wouldn't have much meat left on either side of a 90mm stud, not that it has to do much other than sit there. As I am thinking this one through, I imagine it would be very hard to get the angles right for each cut etc.

No chance of placing the basin on the outside wall? What about in the corner? I assume the dunny is at these points otherwise you would've done it! Personally, if I was absolutely committed to doing it, I would probable cut into the partition wall and run the pipes inside it - but I would probably cut notches in to house the waste, then pack the wall out with 42mm battens and refit the plaster.

interesting project!

[notenoughtoys]

One thing you didn't mention is to build a cabinet/vanity against the wall across to the outer wall, which is where the plumbing is normally concealed. Is there space to do this?? If so it would appear the most straight forward to me. If not the perhaps your diagram may require some more detail to show what's possible. Or as has already been suggested, run against the wall and box it in either down low as a skirting board or up high and utilise as a small shelf???

Bob K

[Vernonv]

Thanks guys. I have amended the drawing to show why I can't put the basin against the outside wall.

I must admit that I prefer the "concealed in wall" option the best - I'm just not sure if it would be considered acceptable practise.

Anyway ... keep the comments flowing.

[seriph1]

OK - I suggest running the waste and feed pipes internally through the studs (notched out, not drilled through in the case of the waste) and then reinforcing the outside of the stud with a piece of 250mm by 3mm steel strap that has been rebated to finish flush....easy.... then plaster, but importantly, make sure all internal joins are behind an access panel under/behind the vanity. That way you'll know any leaks are not behind the wall except where you can get to them.....

[Vernonv]

Thanks Steve,
I was starting to think the same as you in regard to notching out for the pipe and then steel plating (flush). I think it will be the easiest (and cheapest) solution, while still maintaining the structural integrity of the wall.

Thanks for the tip about making the joins accessible ... hadn't considered that.

[bricks]

Just a couple of questions?

you should buy a basin with built in overflow as there isn't a floor trap in your toilet.

If going direct to drain the pipe can only be 2.5m long or you'll need a vent on it.

What is on the other side of the basin wall? Is it possible to go straight through the wall to surface mount on the other side.

As far as the notching of studs? I'm usually asked to penetrate the center of the stud and leave the 2 faces intact. making the holes as small as practicable.

How were you planning on joining to the drain?

[Vernonv]

Hi Bricks,

you should buy a basin with built in overflow as there isn't a floor trap in your toilet.

There is already a floor drain in the toilet - near the outside wall. It just opens to the outside (i.e. it's not plumbed into the septic tank).

If going direct to drain the pipe can only be 2.5m long or you'll need a vent on it.

What do you mean by "direct to drain"?

What is on the other side of the basin wall? Is it possible to go straight through the wall to surface mount on the other side.

Study. I don't really want to run the pipe into there if at all possible

As far as the notching of studs? I'm usually asked to penetrate the center of the stud and leave the 2 faces intact. making the holes as small as practicable.

That should still be achievable. The room will be gutted, so I will have good access to the studs.

How were you planning on joining to the drain?

I was going to join into the main line to the septic tank (see photo). Basically I was going to have an "bottle trap" under the basin, then going into the wall, then running inside the wall, coming out of the outside wall above the floor drain outlet (we have changed our minds and will be putting the basin on the opposite wall to the original drawing) and then directly into the main pipe to the septic.

Or would I be better off running the drain into the existing vent pipe??

Your advice (and anyone else who wishes to contribute) is most welcome.

[bricks]

Without seeing the exact layout of your drainage, I can't be 100% sure, but...

If you change the vent pipe to 100mm atleast until you get above the basin connection, and connect the basin in using a 45 degree junction then I don't really see why you cant connect into the vent pipe- changing it into a waste stack.

Then using stack rules you don't need to vent the line if it's under 10m long and has only one fixture to it, and the fixture is 'p' trapped. However for the purpose of good flow please upgrade the pipe size to 50-65mm if possible once you get outside the building. I would still try my hardest to make the pipe less than 2.5 meters long, this allows for either scenario.

Remember if wall mounting your basin that you probably need to put extra timbers in to hold the wieght of it, And a good height for basins is 865mm to the basin top.

[Qldp]

If I was doing the connection I would go for the vent. A simple 50mm square junction with a 40mm lit. For the amount of water you are going to use you could always run a pipe straight on to your plants.

I have notched out the studs plenty of times, if it is not a load bearing wall what are you worried about. Only notch out as much as you have to.

Your other option which is not as neat is to get a vented pan and connect straight to the pan. You would have an exposed waste pipe though.

[Qldp]

Plumbing is simple keep it that way.

On my first day as an apprentice I was told the 3 rules of plumbing.

1- ???? flows downhill

2- pay days thursday

3- all bosses are ?????



You can only run a basin to a stack a max of 2.5m. AS3500
p.s. this rule is B.S. join into the vent and keep it simple.

[seriph1]

Does that mean bosses flow downhill?

[Qldp]

Somedays you may feel like pushing them down a hill.

S.H.I.T. flows downhill

[Vernonv]

Thanks for the info everyone. It has highlighted my serious lack on knowledge on the subject and has forced me to do a bit more research (and that's always a good thing).

OK, so I'll run the pipe through the wall studs, out the brick wall, and across to the vent pipe. I'll increase the diameter of the basin drain pipe once it leaves the brick wall and make the connection to the vent using a 45 deg. junction into 100mm pipe.

[wonderplumb]

I'd say go into the vent, reducing the 4" to 65mm, have a 65mm junction, take the vent straight up off the wing of the junction (reducing it to 2") and have a 65mm 90 off the top of the junction to pick up your basin. You are then simply rolling the stack and taking the vent off before the last fixture and sticking to drainage rules. You then have 10metres that you can run the branch drain to the wier of the trap, the 40mm waste pipe off the basin must not exceed 2.5metres, but bare in mind that if you P trap the fixture through the wall you must install a tapered/concentric reducer as close as possible downstream of the trap. BTW, they call them Level Invert Taper reducers but infact its the soffit that must remain level.