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Everything in a single services trench — what goes where?


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This seems to be the standard cross section of a services trench. For my build, I am thinking of having a single combined services trench bringing absolutely everything into my utility room so I am wondering how to to fit everything in:

  1. Why the 350 mm radius gap between the water pipe and the gas pipe? And why the separation between the other pipes?
  2. Where do drain pipes go (foul and rainwater)? Could they go in the gap underneath the gas/telecom/electric pipes/conduits? My falls would mean that they could well fit there nicely.

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We used a 300 wide trench and all our services are in duct. I did bury the water on the left, then back filled with 100mm soil and then laid the other three on the other side of the trench gas, comms, electric (left to right). The separation thing feels a bit daft as at each end they all get brought together in the building.  

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Thanks @MikeSharp01. That's my main open question for me now. Whether I can run the drainage pipes x2 (foul and rainwater) into a single service trench with water, gas, telecoms and electricity or whether there is some fundamental reason why I shouldn't do that.

 

Anyone know?

Edited by Dreadnaught
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As long as your services are in ducts, IE you can replace the cables and water / gas pipes without digging the whole lot up I cannot see a problem. You dont want to have to dig up your drains to get at the water pipe below or even dig up the water pipe to get to the drains, although I assume the drains will be above the ducts, do you! 

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I don't think it's a good idea to fill a narrow trench with all the above tbh. Maybe a much wider single trench but not 'squeezed' in like sardines. If you ever needed to replace a section of the drain pipe then you'd have to excavate a long enough trench to lift the cables / pipes out of the way to facilitate further excavations to suit. 

Typically these services go down and are then never seen again, so down to paranoia to some degree, practicality to another. If, for arguments sake, you were a developer, perhaps you wouldn't really give a hoot, but if you owned this for the rest of your days then maybe worth a second thought.....

A machine driver can blast through ground works like my kids go through food and clothes, so personally I'd just stump up the extra for the fines ( sand / dust / pea gravel etc ) and set the services into one 'side', and the drainage into the other.

Segregation is nonsense, given what I've uncovered over the years!!!    

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I've bucked the trend I guess. I've water in first, in a 750mm deep trench but in a (blue), 63mm duct. Then the plan is green duct on top for CCTV and that's it. 

 

Of course it's now so long since I laid the water main and sand blinded it its partially self back filled, so I'll need to re dig a bit to lay the green duct! 

 

There are good (in my head) reasons why the green duct didn't go in, mainly SWMBO's reluctance to let me dig the front path up. A trench along the front of the house would have let me route water straight to the kitchen side of the house where tbh it always should have come in ideally. Similarly the CCTV duct could go to the eventual DVR position a lot easier. She just won't think big!

 

?

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I shared our trench with the guy building next door. He had put a 50mm perforated yellow duct in for his Gas and then we had a delay getting the road permit (not our fault) and consequently it has been 6 months since he put the duct in. Gas was due to go in last week and they only managed to pull the pipe about a metre before it jammed due to the duct being silted up. The gas connection company said it should have been a 75mm duct and not a 50mm which was not specified on my next neighbours forms. He has now dug up the old duct and just put the gas pipe on sand and filled the trench in.

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17 minutes ago, Dreadnaught said:

 

Out of interest, why was it perforated duct? I assumed those were used only for drainage solutions.

 

I suppose in case there is a leak so the gas can dissipate.

 

We had a mish mash of services all over our plot - gas duct from street to house (more or less straight line, perpendicular to house), water and BT came in from other side of plot so ran diagonal over plot, electric from site kiosk to house and gate controls chucked in as an afterthought.

 

Fouls ran on other side of plot (same as water and BT) as that's where the sewer connection is and there is a 45 degree run from front of house to that also.

 

Unless you're doing a road crossing, I'm not sure why you want everything in the same place. I have zero intention of touching any of it ever again!

 

Ground worker had no issue putting what needed to go where and doubt there would have been any material saving anyway.

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2 minutes ago, Bitpipe said:

I'm not sure why you want everything in the same place.

 

Fine question. Three reasons. (1) the trenches on my plot need to be dug by hand through and tree-root preservation zone, watched over by an arboriculturalist with his meter running, so keen to make them as simple as I can; (2)  I realised everything will start from one point and generally needs to end at roughly the same point within the house; (3) I like neatness and simplicity, :D.

 

What do you think?

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1 hour ago, Dreadnaught said:

 

Fine question. Three reasons. (1) the trenches on my plot need to be dug by hand through and tree-root preservation zone, watched over by an arboriculturalist with his meter running, so keen to make them as simple as I can; (2)  I realised everything will start from one point and generally needs to end at roughly the same point within the house; (3) I like neatness and simplicity, :D.

 

What do you think?

 

@Onoff 's 'creative' suggestion aside, that does make sense!

 

Is your electric ducted in from the main supply and will meter termination be in your house or are you taking SWG from a kisok where the meter is terminated?

 

Reason is that some DNOs want to see the trench open with the duct in it before they pull through, which may complicate things for you. If its SWG from your own kiosk then that's not an issue for them.

 

Also, fouls need a fall, (services don't obv.) so that may further complicate things depending what the inverts are between you and the sewer.

 

Rainwater should be going to a soak-away (or harvesting tank) which would not necessarily be in the same direction as the fouls?

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Thanks @Bitpipe.

 

Electricity is already in. I took advantage of neighbouring development to buddy-up and have it connected when they had the road open. I have attached it temporarily to a fence as a TBS. I am assuming I will need to pay to have it moved again into the house but I honestly have not given it thought yet. Good point about the DNO perhaps wanting to look in the trench. I have made a note.

 

Re fouls, yes falls look OK. There is a slight slope on the plot in my favour and the foul sewer in the road is quite deep (1.2 m).

 

Rainwater will be discharged to a stormwater sewer in the road, which is next to all the other pipes in the access road. No soakaway (in fact months of work, and the addition of a green roof to the design, because there was no possibility of having a soakaway). Only concern with the SW sewer is that sewer it looks to be concerningly deep (2.2m) so will need quite a hole.

 

My plot is quite orderly in one respect. All the services, without exception come on the plot together in one corner and my utility/plant room is at the diametric opposite corner, as is the single downpipe from the gutters from my flat roof. A mammoth trench connecting the two points appeals to my sense of orderliness :D 

 

D.

 

(TBS = "temporary builders supply" of electricity).

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19 hours ago, Dreadnaught said:

 

Out of interest, why was it perforated duct? I assumed those were used only for drainage solutions.

I think it was stated in the spec so gas can dissipate into the ground in case of a leak

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