MikeSharp01

Merits of Water pipe in duct.

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Wondering what the merits of putting water pipe (MDPE) in ducting is? Unless you lay the ducting reasonable straight getting 32mm MDPE through a 50mm duct would be difficult, so bigger needed, then there is the fact that MDPE is fine directly in the ground, and away from harmfull UV there as well. Got to lay the water to the phase one this week and am wondering if I should get some ducting or not?

 

PS assuming that I should not put any connections under ground anyway.

Edited by MikeSharp01

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I have put our water pipe direct into the ground as I did not see any benefit from using a duct. I did put a bit of duct over it where it came into the house just to protect it from the whacked stone and concrete when the floor went down ( but the builder thought I was OTT. I would say however that you need to protect any pipe at the ends that are having fittings as the pipe can get scratched and I have a couple of weeping joints where the pipe got scratched.

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My reasoning was that my ground is full of flints and adjacent tree & bush roots. So added mechanical protection. I put 25mm MDPE down a 63mm OD duct around 40m run without a problem.

 

20161001_165048

 

The hardest but was getting a 1m bit of 22mm pipe insulation down between the duct and MDPE where it comes up through the suspended floor. Tapering the insulation with a craft knife and some silicon spray sorted it!

 

But then what do I know, I even duct SWA just in case..... :)

 

 

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Either in a duct or in soft sand is standard. The theory being that the pipe "pulses" with water demand which could cause a stone, sharp object etc in the ground to slowly wear through the pipe. In practice I cant see it being that likely but for the price of a bit of ducting or a bulk bag of builders sand do you really want the grief? We ducted all our runs as the ground is full of rocks and stone.

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I even buried my duct in sharp sand as I had jumbo bag sitting there. I ran out.....so used a half bag of ballast.....still not enough so more (sharp) coming this week. Interesting about the pipe pulsing!

 

SAM_3963

 

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1 hour ago, Onoff said:

Interesting about the pipe pulsing!

Yes it is. I think I will get some duct as it's going through wacked base in places and will allow a new pipe to be fitted if ever needed. Ducting does have a risk in that of the pipe does burst the water will fill the duct and probably the house! Anyway thanks all, know exactly the way to go. 

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Take out the rubber seal in the duct so if in the billion to one chance it bursts water can escape.

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Perhaps seal the duct to the water pipe inside the house but leave it open in the meter box or whatever is at the other end. I did not use duct outside the house as we are in pure clay and even the electricity cable laid by SWEB left out the sand when they back filled the trench.

Edited by joe90

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Most water boards specify the duct is sealed where it comes up into the house. I thought it was as much for preventing gas  (be it methane, natural, radon?) ingress as water.

 

I poured Wiska Gel down mine. The foam seemed to act as a plug. It's magic.....actually that's Magic Gel but either would do. :)

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Would need to seal it for air tightness purposes. Anyway pipe and duct coming tomorrow.

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7 minutes ago, MikeSharp01 said:

Would need to seal it for air tightness purposes. Anyway pipe and duct coming tomorrow.

 

I dream of air tightness..... :)

 

Did you go for blue duct?

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1 hour ago, Onoff said:

Did you go for blue duct?

Yes I did. It's going to be interesting because I will have to thread the pipe and then roll it up for the most part as the ditch for the services cannot be dug until the existing house is finally cleared which I cannot do until the phase 1 slab is done. Let you know how I get on.

 

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4 hours ago, MikeSharp01 said:

Yes I did. It's going to be interesting because I will have to thread the pipe and then roll it up for the most part as the ditch for the services cannot be dug until the existing house is finally cleared which I cannot do until the phase 1 slab is done. Let you know how I get on.

 

 

You can get duct joiners - ,cut and trench as much as you need and fill the ends to stop muck getting in then mark the end on the surface. When the house has gone, dig up and attach the rest and feed the MDPE in and job done. 

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The ducting I got came with one duct joiner per roll. They were available separately too.

 

Just don't lose the draw string or it's the plastic bag and vacuum trick!

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Got it all done today, despite being very cold to start with but the sun came out and warmed up the water duct, pushed all 50M of 25mm pipe through the duct, no draw string needed just a good dolop of silicone grease, took about 20 mins of concentrated effort to get it through (protected the end with duck tape). Then I just laid the three ducts ( water, electricity & comms) in and started to cover with type 1, will finish Thursday and start with the polystyrene insulation and former for the slab.

20161108_160254.jpg

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I though you were going 32mm water pipe in the OP? Be easy to upgrade now though won't it!

 

Job's a good 'un!

 

Cover it up quick so no snotty utilities company tries to say you've not maintained their required distance between services!

 

Don't forget with your comms and leccy to leave a decent draw string in there when you finally pull stuff through.

 

 

Edited by Onoff

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They are 150mm apart user the slab and they then go into standard layering through the garden down to the utilities center in the front garden. I chose 25mm for phase 1. It's only a garden room with a loo and shower so does not need 32mm. Will use 32mm to phase 2 the main house.

Edited by MikeSharp01

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just resurrecting this thread;

 

We are in the process of preparing the insulted foundation. Should the water pipe (MDPE) be contained within a duct as it runs through the slab? I know that that type of pipe is generally not run within any ducting.

 

 

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As I understood it the pipe doesn't have to run in a duct but I thought that it has a bit more protection in a duct and if I ever have to replace it under the slab I could bu just pulling / pushing a new length along the duct.

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I ran our water pipes in ducts under the slab, for two main reasons.  The first are as Mike has said, the second is that sooner or later there is going to be a mains water connection available in the lane in front of the house, as the 80+ year old cast iron pipe that's there at the moment will have to be replaced before long.  I wanted the option to have an easy mains water connection if it became available and if we felt it worthwhile, so I ran an extra 100mm blue duct to make pulling a pipe through a lot easier in the future.  This duct also runs under the path around the house, and terminates close to the boundary, so a short trench and a bit of new pipe and we could be easily connected at probably the minimum connection charge.  The duct is sealed at both ends, and has a foam plug in the house end to prevent heat loss.

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I've run mine the complete length (25mm in 63mm pipe). I'd say it's daft not to under a slab. Primarily did mine in duct because of sharp flints everywhere.

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When we did our conservatory we put it in ducts, and then added a spare duct run to where we *may* need something in future.

 

Imo it is just sensible.

 

@volcane

 

46 minutes ago, volcane said:

We are in the process of preparing the insulted foundation.

 

What is one of these insulted foundations, then? xD

 

Did you call it a barsteward?

Edited by Ferdinand

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And remember to leave the end pointing down and well sealed if you need to leave it for some time :-).

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17 minutes ago, Ferdinand said:

When we did our conservatory we put it in ducts, and then added a spare duct run to where we *may* need something in future.

 

Imo it is just sensible.

 

@volcane

 

 

What is one of these insulted foundations, then? xD

 

Did you call it a barsteward?

 

'Insulted foundation' a typo but brought a smile to me! as insulted is actually a good description and its been called a lot lot worse!!

 

 

Personally I would be much happier with the pipe in a duct, currently the pipes installed are the two providing the water to outside taps at the rear of the garage. I'll make sure the incoming mains will be within a duct.

 

thanks, I may try and put up a few snaps later

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