Chasing water pipes into wall - opinions

confused30000

I apologise in advance that this might not make sense or be full of silly/obvious questions, but I am a novice at all this!

We have recently knocked through from our kitchen to a new extension to create an opening. Various things have been moved from the wall that was knocked through, including the fuse board and electricity meter. The walls have then just been plastered over last week.

One thing that remains though, is water pipes. This is my first time dealing with this so apologies if this is wrong - we have two pipes that come from the bathroom upstairs, directly above the kitchen, down the kitchen wall and then make their way to the sink behind the kitchen units. During the knockthrough and to make room for the plastering, the builders have put a right angle pipe in and replaced the old copper (I assume copper) pipe with plastic pipe. They are currently away from the wall as the plaster dries.

I think these two pipes are hot and cold water - they are 15mm piping going from the label on them so too narrow for one to be waste I assume? Photo attached of the current set up to hopefully help (please excuse the mess!)



I thought that these pipes were going to be in the wall (we were away during the plastering phase) but is there a reason they couldn't be? I haven't yet had chance to speak to the builder about it. I believe it isn't common practice to chase waste pipes into walls, is the same true of hot/cold water?

We are having a new kitchen fitted - the fitters are coming for a final survey and said they could probably bring the pipes straight down vertically alongside the edge of the new opening, box them in with plywood that could then be painted the same colour as the wall. 

Was just looking for opinions really - would you do that or explore the idea of chasing them into the wall, even though it would mean disturbing the newly plastered wall?

If it helps, it's plasterboard onto the brick of the external wall (I'm not sure if it's D&B, sorry!) which then has insulation and the outer brick.

Again, sorry if that is all confused word soup, any help gratefully received!

Ebe_Scrooge

I'm no expert, but I'd be very wary of chasing in water pipes.  If for no other reason than, should a leak develop, you probably won't know about it until a lot of damage has been done.  Also, I'm not sure if there's a danger of the plaster reacting with the copper (assuming those plastic pipes are just a temporary measure whilst work is ongoing).

I'm sure more knowledgable folk will be along soon, but those are just my thoughts as a layman

Section62

confused30000 said:

I thought that these pipes were going to be in the wall (we were away during the plastering phase) but is there a reason they couldn't be? I haven't yet had chance to speak to the builder about it. I believe it isn't common practice to chase waste pipes into walls, is the same true of hot/cold water?

We are having a new kitchen fitted - the fitters are coming for a final survey and said they could probably bring the pipes straight down vertically alongside the edge of the new opening, box them in with plywood that could then be painted the same colour as the wall. 

Generally I'd avoid chasing pipes into the wall if possible, partly due to the leakage issue, but also that I'd want hot pipes well insulated and the amount of chasing necessary to accommodate the insulation starts to impinge on the structural strength of the wall.  Other people may not care about either of these issues.

In your situation chasing the pipes in on the alignment they are curently on may well be problematic because (you'd hope) there should be whatever lintel/beam has been installed to create the opening not far beneath the finished surface.  They shouldn't be cut into, and ideally nothing should be done which affects the beam's bearing/support.

Boxing in on the middle of a wall like that isn't a great solution.  Usually it is better to have boxing in run along an internal corner where it is less obvious. Maybe talk to the kitchen designers about alternative routes?  Ultimately you need to balance the cost of the solution against the aesthetics and energy efficiency.  Where that balance lies is a personal choice to some extent... and ideally is something to figure out before work starts, rather than have an 'Oh whoops' moment after the plasterer has been and gone.

Leon_W

Personally, I'd have chased those in.  I'm no plumber but have done quite a few over the years without problems.

I'm not sure I'd use plastic as I'm a bit old school, but would have used wrapped copper pipes in a solid wall trying to avoid any hidden joints.

If I'm reading your post correctly you've got insulated plasterboard over brick ?  This would have been the ideal time to hide the pipes but what's done is done. 

Bendy_House

confused30000 said:

I thought that these pipes were going to be in the wall (we were away during the plastering phase) but is there a reason they couldn't be? I haven't yet had chance to speak to the builder about it. I believe it isn't common practice to chase waste pipes into walls, is the same true of hot/cold water?

We are having a new kitchen fitted - the fitters are coming for a final survey and said they could probably bring the pipes straight down vertically alongside the edge of the new opening, box them in with plywood that could then be painted the same colour as the wall. 

Was just looking for opinions really - would you do that or explore the idea of chasing them into the wall, even though it would mean disturbing the newly plastered wall?

If it helps, it's plasterboard onto the brick of the external wall (I'm not sure if it's D&B, sorry!) which then has insulation and the outer brick.

Again, sorry if that is all confused word soup, any help gratefully received!

Hi Confused.

I guess the reason they didn't sink the pipes is because there wasn't a plumber there at the right stage to discuss this option, but just the builder - and they just got on with their job.

That is a thick ex-external - wall, and the plasterboard has been likely D&D'd over it, so plenty of opportunity and room to do this. If the p'board is insulated - probably not if that section of wall is now fully internal - then that would make it super-easy to do even now.

So, ask if that is insulated p'board, and whether it's D&D'd.

Solutions? Is there a wall unit going there? That will hide most of it, and the rest can be boxed in. But, personally, I would channel out and bury them in a single length (so no joints) of plastic (no risk of corrosion). But I would also insulate both pipes as far as I could - the hot to keep the heat in, and the cold to prevent a cold line which could attract condensation.

What sort of DHW system do you have - vented? Unvented - pressurised? If the latter, then I have a bludy brilliant idea, and it involves running the kitchen sink + W/M supply in 10mm, which will allow a greater level of insulation over it for the same amount of channelling. Discuss with plumber, and hopefully they'll agree that the narrower pipe won't affect the flow to any significant degree.

IF it's a pressurised system.

confused30000

Thank you all, a mix of opinions on whether chasing is a good idea or not! Seems opinion is spread across the internet.

I'm afraid I'm not sure what DHW system we have, I'll find out! I'm kicking myself that this wasn't 100% sorted before the wall was plastered, so many moving parts in this project and this got missed. 

While it seems such a shame to do it after the wall has just been plastered, do you know roughly what the cost of chasing these in would be? I imagine it would involve chasing about 6 feet in total perhaps? Hopefully the pipework that is there would be sufficient. I am pretty sure that the plaster on that wall is D&D but can't be 100%.

Plumber and plasterer from the kitchen firm should be coming for a site visit so I can ask them of course, just wondering if anyone had any ideas ahead of that on cost and disruption! The plastering was a long and messy process, does plastering after chasing involve more plasterboard or is there another method of covering after it's done?

Section62

Bendy_House said:

That is a thick ex-external - wall, and the plasterboard has been likely D&D'd over it, so plenty of opportunity and room to do this. If the p'board is insulated - probably not if that section of wall is now fully internal - then that would make it super-easy to do even now.

How I wish I had X-ray vision for a job like this.

There's an area of plaster the pipes need to pass through which has not dried as quickly as the rest.  If chasing in is going to be the plan then the first thing to figure out is what is going on in that area. The working assumption should be that the wall isn't uniformly constructed... and then there is (hopefully) a lintel/beam in there somewhere.

I wouldn't say there is "plenty" of room to chase in just on the basis of the picture alone. I could guess at what is going on, but not say with enough certainty to justify wrecking a recently plastered surface on the off-chance I've guessed right.  Discussing other options with the kitchen fitters ought to be the starting point.

FaceHead

So currently it looks horrendous. The options are box or chase. 

What is the wall construction? Vertical chases can be up to 1/3 the thickness of the wall/leaf before they cause a structural problem. (Horizontal chases 1/6, so these are indeed best avoided). In the 9" solid walls in my house that means a 2" chase is permissible which is enough for the pipe and a bit of insulation.

Clearly there are more ideal solutions with more forward planning, but at this stage I would chase it in and add as much insulation as you can (or maybe just some expanding foam), whilst keeping within the 1/3 thickness limit.

tacpot12

I think I would box them in. Two 15mm pipes are not going to require a very deep box, it might only stick out by 25mm, and the pipes remain accessible in case of leaks. 

Gavin83

To answer your questions yes, they'll be the hot and cold water feeds for the sink/appliances. Waste pipes are a lot thicker, starting at 32mm.

What are you plans for that wall? I'm in the camp of people who wouldn't chase water pipes like that. The easiest solution would be to run them down the wall and box them in, although the feasibility of this would depend on what your plans were. The other option is to re-route the pipes but given you've already plastered and depending on the layout of your house this might now be challenging.

FreeBear

Bendy_House said: Solutions? Is there a wall unit going there? That will hide most of it, and the rest can be boxed in. But, personally, I would channel out and bury them in a single length (so no joints) of plastic (no risk of corrosion). But I would also insulate both pipes as far as I could - the hot to keep the heat in, and the cold to prevent a cold line which could attract condensation.

Could use copper pipe - 15mm is a nice fit inside 20mm plastic conduit which would protect the copper from corrosive plaster/cement. Recess a backbox in the wall where the pipes exit the chase. If there is going to be a leak in the pipe, a joint is the most likely point. Fix a strip of stainless steel over the top of the pipes before plastering over the lot. Stainless steel can be a right pig to drill, so should stop most people from drilling a hole in the wall and going through a pipe.

I have some pipes chased in to the wall in my kitchen. Have since come to the conclusion that the wall is sucking quite a bit of heat out of the HW pipes, so will be moving them to surface mounted. Plenty of insulation to go round the pipes, and will be boxed in.