Silly q's about running pipework in concrete floor and walls

10 Mar 2008
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United Kingdom
Hi sorry if these questions have been asked before but I have searched the forums and have not found an answer.

In my front room I have an unsightly CH pipe drop in the middle of the wall. I dont want to box this pipe in because (a) it will look silly with a box section sticking out the wall in the middle of the room (b) it would affect furniture being pushed tight to wall and (c) (most importantly) it will annoy me :)

So that leaves me with the option of chasing the wall and burying the pipework under the plaster then channelling out my concrete floor for the pipe to run horizontally to the radiator.


I am considering putting plastic pipe in the chase as i can use one continuous run (I have never sweated copper pipes before and not too sure I want to). I intend on placing the pipe in a conduit pipe similar to this

q1) If i chose to replace the copper pipe with flexible plastic pipe for this radiator can i just use a pushfit onto the existing copper pipe in the ceiling void (i can acess it easily from the room above).

q2) The existing pipework is 15mm do i need to use 15mm plastic (sorry if this seems a stupid question) - assuming the 15mm is the internal pipe diameter.

q3) How deep / wide do i channel the chase - my wall is the outer wall (brick). Can i clip the pipe-in-pipe directly to brick. I am thinking of 30-40mm deep to allow for the uneveness of the chase and about 55mm wide to allow for the clips.

q4) I planned on chasing deep enough so that i can plasterboard over the chase. Am having wall reskimmed anyways - is this appropriate.

q5) Along the horizontal concrete floor run. How deep do i run the chase - again i am thinking 55mm wide and 30-40mm deep.

q6) How far from the skirting should the chase be - i am thinking ~150mm is this too far / too close

q7) After i lay the pipe in the floor what kind of mechanical protection do i need to cover it with - i have googled for steel trucking strips but cannot find anything suitable. Can anyone suggest the correct keywords for me to search on ( i dont know the terminology..sorry )

q8) To avoid joins i intend to bend the plastic using the external formers (again i do not know the correct name/terminology so apologies in advance). If i am bending the pipe; from the vertical drop to the floor i will surely have to dig a deeper channel to allow for the curvature how much extra depth do i need to channel. I cannot seem to be able to calculate this.

q8a) Inversely to Q8 when i bring the pipe out of the floor to the radiator. I shall need to dig a deeper channel again to accomodate the bend.. again - how much extra should i allow for this.

Thanks in advance for any answers provided.

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The answer depends on the diameter of the pipe/duct you intend to use plus apparently plasterboard.

I dont understand what you said about this being an outer wall.

My obvious fear is that you will be chasing most of the way through the wall and not leaving enough strength.


Thanks for the reply.

Yes your right my phrasing of "outer wall" is irrelevant - sorry. What i meant to imply/say was that the wall in question is not an internal wall but is the permiter brick wall.

As far as i know its straight onto brick - the house was built circa 1970's and i am fairly certain there is no block behind it.

I too am worried that i may be attempting to chase too deep...
Generally you should not chase more than 1/4 of the depth into the wall.

A 1970's properly would usually have a cavity wall with 100mm insulating block on the inside with about 12 mm of plaster.

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Ping, pipework running down the centre of a wall Is ugly, and , generally, poor practice. Can you not relocate it to the corner, it would look tidier, and if you like, it would be easier to box in.
Thats good news ... hopefully i am talking total boll**.

I based my assumption on my memory of drilling into the gable end wall and there being no block. However my memory could be deceiving me; it was a long long time ago..


I have considered this approach - the closest wall to the radiator houses the gas and electric mains; the previous owner must have felt this was too ugly to be seen in the living room so built a half height cabinet around it. So i believe that wall is not an option.

If i go to the otherwall then there would be a long horizontal pipe run to the radiatior. Boxing-in in this corner would then restrict the usage of furniture. This wall is the alcove around the fireplace.

Sorry for the diabolical diagram...only had paint to hand and am at work :)

Happy to consider all options thanks
There's no reason you shouldn't run pipework in the same cupboard as your gas an electricity supplies. After all, pipework isn't designed to leak, and it could just as easily leak anywhere else in the house that happens to be near the electrics.

There's some information on maximum permitted depth of chases from one of the LABC's here.
@electronicsuk, thanks for the reply.

In the corner of the room - to the left of the window frame all the cables for the house run here going upwards and onwards. If was to run the new pipework in this area - i would have to go around this mess notching out previously drilled noggins etc.

To the right of the window frame runs the shower cable to the fuse box and light switch cabling. Also a gas pipe which runs up to the ceiling then along to the boiler.

The cabinet is split in two along the vertical with one half housing the electric meter and the other half housing the fusebox (ie they are back-2-back). The other half of the cupboard houses the gas meter and periphery.

Also when i get to the bottom of the wall i would have to run a 15mm pipe horizontally around the gas meter and fuse box; drill a hole in the cabinet and run a pipe along the wall to the radiator.

I am trying to avoid having a long run of visible horizontal pipework - if could chase into the floor under the wooden cabinet, i guess it could be an option ?? any thoughts?
I guess you should be able to chase fairly deep into the floor. You don't want to go so deep that you puncture any damp proof membrane that might be down there, nor so much that you separate the slab in two. Might be worth asking on the building forum as to how deep the slab and screed is typically poured.

I am trying to avoid having a long run of visible horizontal pipework - if could chase into the floor under the wooden cabinet, i guess it could be an option ?? any thoughts?[/quote]

That is normally not a problem.

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