Land Drain & FoulDrain - Same Trench

[dunny]

Hi all,

Is there any reason why I shouldn't put both a surface water/land drain pipe and a foul drain pipe in the same trench?? They are going to different outlets but in the same general area and from the same building.

Thanks

D

 

[oldbutnotdead]

As long as the land drain is surrounded by porous material (pea shingle as required for the foul drain works fine) then yes it'll work

 

[noseall]

Hi all,

Is there any reason why I shouldn't put both a surface water/land drain pipe and a foul drain pipe in the same trench?? They are going to different outlets but in the same general area and from the same building.

Thanks

D

No probs.
You would often find leccy and water in the drainage trench also.

 

[Ian H]

Could you combine them?

If your on about the perforated land drain, the water around it could affect the ground and your foul drain could settle. But it will probably be ok.

 

[dunny]

Could you combine them?

If your on about the perforated land drain, the water around it could affect the ground and your foul drain could settle. But it will probably be ok.

Soddy for late reply. Cant combine them as the fould goes to a septic tank.

 

[dunny]

Another quick question on this. I read that for 110mm pipe you should use 10mm pea gravel but is there anything stopping me use 20mm?

 

[oldbutnotdead]

The building inspector for one. I'm not an expert but the problem with larger gravel could be ending up with too many voids in the fill and excess settlement of the pipe- if you're on a shallow fall then you could end up in real bother with a low spot. I wouldn't chance it myself- lot of work to correct any problems that show up down the line.

 

[dunny]

Thanks. I will go for the 10mm as recommended.

D

 

[Ian H]

As above.

I've seen plastic pipes bedded on the wrong stuff, worst I've seen is something pressing into the pipe, trying to, but not quite piercing it. It was prabably a slate or something very sharp.

20mm would work but if building control refuse it then it would be a pain to swap.

If building control aren't involved and you have a load of 20mm to get rid of, chuck it in!!