New kitchen, drainage advice please

[rhino666]

Hello

I am fitting a kitchen in a new room without services. Looking to tile the floor so everything under the tiles really needs to be fit and forget.
Looking for best advice on fitting drainage for the sink and dishwasher please.
Photos of situation below. Sink will be under window and dishwasher next to that, so one drainage pipe to exit property.
The path level, outside is 8cm above the concrete base under floorboards. If I hole drill the wall at the lowest convenient point, I would be around 18 inches above the path height.
Ideally the exit pipe would be hidden outside but I am thinking that will not be possible but grey pipe would show up far less than white.
Dig a hole in the path next to the wall, install a trap and then join up to the 100mm plastic drainage pipe running across, about 3 metres away?

 

[Deleted member 120897]

I’m struggling to believe that if you drill a hole, it will be 18” above the path?

 

[rhino666]

I’m struggling to believe that if you drill a hole, it will be 18” above the path?

The path level is quite a lot lower than floorboard level and only 8cm above the concrete base which is 14-15 inches below the floorboards.
If I drill a hole just above the skirting board height, it will exit a little over 18 inches above the path

 

[oz-plumber]

Why wouldn't you install a trap under the sink and then connect it directly to the drain?

 

[snowhead]

Just a couple of thoughts;

Paint the pipe a colour that blends into the wall, it doesn't have to stay Grey / Black / White (dull the pipe surface then paint gloss direct onto the PVC, don't use undercoat).

When you say Trap I assume you mean gulley, either with hopper or with 40mm x 110mm adapter to Underground?

If the floorboards are actually that much higher than outside then drill through under the floor if you want minimal pipe exposed.

 

[rhino666]

Why wouldn't you install a trap under the sink and then connect it directly to the drain?

Exactly what I am intending to do, trap under sink and then into drain.
Just want to avoid ever having to interfere with the tiled floor that will be installed.
Perhaps I could just drop the drain pipe straight through the floor, run it out through the wall at the lowest point. Could then concrete it in to the top of the new drain with 'p' trap underneath?

 

[rhino666]

Just a couple of thoughts;

Just a couple of thoughts;

Paint the pipe a colour that blends into the wall, it doesn't have to stay Grey / Black / White (dull the pipe surface then paint gloss direct onto the PVC, don't use undercoat).

When you say Trap I assume you mean gulley, either with hopper or with 40mm x 110mm adapter to Underground?
View attachment 81836
If the floorboards are actually that much higher than outside then drill through under the floor if you want minimal pipe exposed.

Thank you snowhead, and yes that gulley looks like the sort of part that will be fitted; think it is also known as a 'p' trap. The hopper fits on top. Just wondering if they do a hopper with a facility to join the 40mm? pipe from the house straight into it? Looks like they do......
110mm Rectangular Hopper Spigot End Underground Drainage - https://www.plastics-express.co.uk/underground-drainage/Underground-Drainage-110mm/110mm-rectangular-hopper-spigot-end-p-pte340?gclid=CjwKCAiAjPyfBhBMEiwAB2CCIrhTsFCLF2vN4SSKVqUgYU4Rizol3px4ttuLIM3rITjgEHl1cNpthxoCj4cQAvD_BwE
If I punch through the wall, just on top of the concrete house base, I would be an inch or two under the path surface outside which should work well.
The pipe would go straight down through the floor and then perhaps 120 degrees across at a bit of a downward angle to the hopper. Guess it's best to solvent the 40mm pipe joins?
If this is in place, dropping through a tiled floor, does it stand a fair chance of surviving without needing to be touched for any reason for say 20 years? Obviously I accept that we would have to be sensible with what goes into the sink/dishwasher.

 

[Timmy D]

If the stack is 3m away, just run the waste under the floor boards internally until you’re at the stack and then punch out through the wall directly into a tee.

 

[rhino666]

If the stack is 3m away, just run the waste under the floor boards internally until you’re at the stack and then punch out through the wall directly into a tee.

There is no stack; the foul water 110mm brown pipe runs under ground parallel but at an angle to the house, so 40mm pipe will go out through the wall and into a gulley. outflow from gulley will probably join a 'y' piece inserted into the foul water pipe.
Almost there with this. Only unanswered question
is the advisability of dropping through the tiled floor into the void and what angle is a sensible drop angle for the foot or so of joining pipe to the square hopper. I was thinking 120 degree, so 30 degree drop but the port receiver on the square hoppers looks like it requires the 40mm pipe to enter dead straight?

Thank you

 

[oz-plumber]

Why do you need a hopper?
Can you just not connect it to the drain directly.

The connection into the hopper will be at the required angle.
They are made that way

 

[rhino666]

Why do you need a hopper?
Can you just not connect it to the drain directly.

The connection into the hopper will be at the required angle.
They are made that way

Ahh right, so the port for the 40mm pipe on the hopper is at an angle; that makes sense, just looks straight in the part photos I have seen and I don't have the part here to refer to.
I was told that the way to handle a sink and dishwasher drainage in this situation was 40mm pipe going into a hopper and gulley('P' trap) and then on through 110mm pipe to join the main foul water pipe.
Are you suggesting 40mm pipe out through the wall and straight into a drainage pipe? Just thinking that the gulley would stop smells coming back up through but maybe the sink trap would be sufficient in that respect.
The other issue with no gulley, is no access to that section of pipe without digging up the path/garden and dismantling.
Got to say, I think the gulley and hopper or at least something that facilitates easy access to that part of the 110mm pipe section is the way to go?

 

[rhino666]

A couple more questions on the 110mm drainage part of this please.

Am I correct in thinking that the best solution for the sink/dishwasher drainage is 40mm internal into a socketed hopper and 'p' trap gulley?
The gulley trap with hopper fitted straight on would leave the outflow pipe only a short distance underground. The pipe I am running to is just over three metres away and perhaps 750mm underground. Am I right in thinking that it is quite usual to extend the hopper height with socketted pipe or pipe and a coupler with 2 sockets?
a 45 degree junction with 3 sockets is what I am thinking of to join the main 110mm pipe run. Am I able to fit the 3 socket junction into a pre-existing pipe run or would I need to lose a socket and join with a rubber sleeve or similar? Just thinking that there is not enough room/flexibility to insert this into fixed pipe so both sockets have enough pipe inserted?

 

[oz-plumber]

For the main drain connection you would need a couple of slip couplings.

Work from there back to you location of the drain coming out of the wall.

Keep the p-trap gully on the same grade as the drain and just intall a riser pipe to the level required.

 

[rhino666]

For the main drain connection you would need a couple of slip couplings.

Work from there back to you location of the drain coming out of the wall.

Keep the p-trap gully on the same grade as the drain and just intall a riser pipe to the level required.

Thank you for your reply. Do you reckon I might get away with one socket and one slip coupler on the junction insert or do you definitely recommend two slip couplers?
The riser pipe you mention, is that just 110mm pipe with a socket or 110mm pipe with a coupler?
I thought my idea of the 40mm pipe going under the floor and out, so no pipe exposed outside was a good idea but others I have spoken to today suggest it is better to go higher out through the wall, above the floor and drop the pipe straight into the hopper. Obviously this would mean pipe showing outside but maybe its the best solution?

 

[plumberservices]

Why do you need a hopper?
Can you just not connect it to the drain directly.

The connection into the hopper will be at the required angle.
They are made that way

Correctly said. Connecting the trap to the drain directly is the most reliable option.

 

[rhino666]

Correctly said. Connecting the trap to the drain directly is the most reliable option.

Thank you for your input. The 'P' trap was always going to be connected directly to the main 110mm foul water drain pipe.
Is that what you meant?