fall on a drain

[diy001]

Hi all, Me and a builder friend are digging out a drain line and need some advice.
The inspection chamber is 1 meter in depth, I need to run the drain 7 meters from chamber, what should the fall be on this? How many cm below ground should the drain be at the 7 meter point?

Also i would like to in future take a drain line to my outbuilding, which is around 6 meters further than my extension plan. I dont what to take the drain there now but would like to have the drain line available outside of my extension for where i'm ready. please advise how i could do this too.

Many thanks in advance.

 

[RedHerring2]

Assuming we're talking foul water here, the fall should be 1 in 40, so that's 25mm for each 1metre=175mm fall for 7 metres, or a further 150mm for the other 6 metres.
You'll need an inspection chamber for the joint for the additional drain. Unless you can get away with rodding access from both drains and a simple y junction.

 

[r896neo]

as red says simply putting in an extra y chamber and leave the plug in the y for future access. I would advise using proper lubricant like silicone grease if you are going to be needing back at the drains to modify as the oft used fairy liquid can set a bit hard and make getting things apart a lot more difficult.

 

[Nige F]

? How many cm below ground should the drain be at the 7 meter point?

.

depends if the ground rises or falls from the datum point.

 

[theoldun]

Hope you do not mind us saying Mr Red, but you not quite correct.
100mm main foul drain minimum fall of 1 in 40 if no WC connected to run. Does not apply to gulley connections.
If one number WC connected to run, fall can be reduced to 1 in 80.
1metre equals 0.0125 fall.
Question is not clearly worded. The new 7m run must be into existing IC as existing IC must already have a flow going down stream, there fore no connection can be made out of IC.
Minimum depth technically in garden areas should be 600mm above crown, but with simple precautions on connections, this can be reduced down to 250mm
oldun

 

[diy001]

Thanks guys, thats fantastic. I have a pretty much straight run from the extension to the out building hence i think i could get a away having a manhole.

Just to be sure, from manhole to the end of extension which is going to be a kitchen is 7 meters i'll have a straight run with 175mm fall. I'll the have a gully outside the kitchen, and off this gully i could take the drain further up to the outbuilding when im ready. Is this correct or i'm totally off mark?

Also

A) is it ok to have a a kitchen drain an a wc waste running through the same pipe?

B) Is it ok for rain water from guttering to go in to gully? might sound a little dumb but ive been told a soakaway is better for something to do with regs.

 

[RedHerring2]

Hope you do not mind us saying Mr Red, but you not quite correct.
oldun

No probs, oldtimer. The question was minimalist so I responded likewise. I'm always comfortable with advice from those more experienced.

In response to OP, your extended 6 metre run won't come off the first gully, the first gully will come off the run, possibly via a 'y' junction. There's a difference.

No you can't necessarily just use the foul water line for surface water. Loads of questions about this if you do a search. Otherwise somebody has to type it all out again.

as red says simply putting in an extra y chamber and leave the plug in the y for future access. I would advise using proper lubricant like silicone grease if you are going to be needing back at the drains to modify as the oft used fairy liquid can set a bit hard and make getting things apart a lot more difficult.

That's exactly what I did when I did the soakaway for the garage 2/3 years ago, and for the surface water off the roof of the extension, now in construction.
I used a short piece of pipe out of the 'y' junction, then a coupler and stopend. I only had to remove the stopend and reused the coupler.

 

[RedHerring2]

Oops, must have pressed the quote button instead of edit button.

Kitchen, batroom, WC, whb, washing m/c are all foul water waste and goes in the same pipe. Rain from the roof is not!

BTW, if the run is all straight, you don't necessarily need an IC, but any more than one 45 ° bend and you'll probably need IC.

I don't know if it's notifiable work. I suspect so.

 

[diy001]

Thanks Red,


3m away from manhole is going to be a wc, and further 4m off that is the 7m point where the kitchen sink will be. Its all straight hence rodding wont be a problem. If this set up is allowed its not going to yield any foul smell in the kitchen or in the garden through the gully is it?

 

[diy001]

BTW, if the run is all straight, you don't necessarily need an IC, but any more than one 45 ° bend and you'll probably need IC.

I don't know if it's notifiable work. I suspect so.

Its all through the regs anyhow, fees have been paid

 

[RedHerring2]

I'd suggest a bottle gulley with rodding access, or a separate access close by, but the bottle gulley is easiest.
The reason for using a gulley is 'cos it has a water trap to prevent smells. Make sure it's set level.

I'd also suggest you run your ideas past the BCO. He'll say yea or nay before you start.

How will you provide rodding access for the WC run?

 

[diy001]

Of course i'll definatley discuss with BCO.

You have me on the toilet WC rodding

I have no idea is the answer to that. The only IC is at the front of the house, and this WC would be 3m behind it. again sorry if this sounds a little dumb, but are you saying i need to have a IC behind the the WC so i could Rod forward in to the IC thats front of the house rather than back?

Just to clarify the the drain from WC will be going in a straight line to the kitchen.

So kitchen waste would be go through WC and then to the manhole.

 

[RedHerring2]

The kitchen waste won't go through the WC! Or is that just the way that you tried to explain it? It'll stay in the run past the WC inlet!
View media item 34097If you look at this diagram, you can see that all parts of the system are roddable.
From the uppermost IC you could rod one of three ways, one of which is into the WC stack.
From the lower IC you can rod either way, and because of the orientation of the 'y' pieces the rods will go straight past.

From the bottle gulleys you can rod the short piece of pipe into the main run.
There's a further IC next door further down the run where you could rod upstream if you wished, but not to be reccommended, I'm told.

This is the kind of thought you need to put in to your layout.

 

[diy001]

thats what i meant.

I may be wrong, but this diagram look as though the drain run is around the out side of the building.
Mine is going to be on the inside. As i m building on the side of the house.

Going back to the illustration, i could use that to maybe better explain my project. The room layout is similar

in my case starting from the top the first red manhole is what takes waste to the sewage in road, now connected to that i would have a drain going straight to the bathroom toilet, and off that i would have a drain going into the kitchen gully. The flow of the kitchen waste will flow through the brathroom drain and in to the manhole.

Is this correct?
As you've explained earlier this wont cause any foul smell into the kitchen or garden, does this still stand?
And lastly do i need to build a manhole or roding access etc for this described set up. Thankyou.

This is my first extension project, hence the many question.

 

[RedHerring2]

Mine is going to be on the inside.

All change! Well, a few things anyway.

I'm getting bored with bits of information trickling out now.
Can we have a diagram of your intentions?