Chasing in pipework

[MetManMark]

All
We have had a few quotes for the installation of a new central heating system. It has some suspended floors downstairs and some solid floors. Some of the plumbers have recommended putting radiators in less than ideal positions such that you could do radiators back to back etc to minimise visible pipework - others have suggested just having 'drops' into each room. We had decided on the later (as they will probably be masked by curtains etc, however, the last chap suggested chasing out the walls to run the pipework beneath the paster (some solid walls with lime plaster - others are lath & plaster). My initial concern was wrt leaks but he suggested that they would be using a single pipe to go from above the ceiling to beneath the floorboard so there couldn't be any leaks in the wall.
We have yet to get the cost of any of these options but what are people's thoughts? What are the downsides to having pipe work in the plaster? Presumably there could be issues with expansion or vibration of the pipes causing damage to plasterwork?
Cheers
Mark

 

[Zebra]

I would think that the main source of damage if you took that option wouldn't be from the pipes once they're in but from the plumbers putting them in i.e. destroying the plaster and moreover the laths. Imagine that you have to get a pipe from above the ceiling to below the floor - you have to destroy part of the wall to do it especially if there is a timber framework in the wall which has be be cut through. Not that I'm saying you shouldn't take that option, and most likely the plumber won't know until they start quite how feasible it will be to do and how little damage has to be done to achieve it. I just know that tradespeople often have little respect for the historical fabric of your building, they just want to get the job done. Not that there's anything wrong with that, just something to be aware of.....

 

[robgil]

I wouldnt chase out a lath and plaster wall. A plumber will do the best they can but wont get over inventive, there are ways and means of putting in pipework without doing too much damage if you are prepared to put in the time and do the extra work.
My house is timberframed with wattle and daub infill's, a false ceiling in the kitchen will contain the flow and return for the top floor plus electrics for the entire house and I am lucky enough to be in the position to be able to put all the ground floor pipework under the floor but to get pipework to radiators is still going to be a challenge. Plus I am not allowed to use solder joints upstairs.

If I were you I would spend an hour or two mapping out where you would like the pipework to run then run this by an installer.

 

[Feltwell]

Plus I am not allowed to use solder joints upstairs.

Why not?

If naked flames with a thatched house is the problem then why not use one of those Antex Pipemaster electric soldering irons?

 

[philpjuk100]

Using one length of pipe will not guarantee freedom from leaks,the pipes will still burst if frozen,(it can happen!) phil.

 

[FamilyWiggs]

I've chased in both cables and pipes. I'd buried them in metal conduit though - just to make sure no future people put picture nails through them! The conduit enables the pipes to expand and contract within them without cracking the plaster though.

 

[d49xc]

Plus I am not allowed to use solder joints upstairs.

Why not?

If naked flames with a thatched house is the problem then why not use one of those Antex Pipemaster electric soldering irons?

He's probably got some "Hot Work" restricstions imposed by the council.
This will probably cover ALL forms of heat - not just naked flames.....(ie sparks possible from an angle grinder as an ignition source)

Usually the hot work is allowed with certain precautions AND some requirement that the site is not vacated by the workers for some time after the last hot work has fininshed (and that will be hours not minutes!) to allow for any smoulding fire to either go out - or start to burn the place down.
So although the hot work is permitted the conditions may be onerous enough that in this case it's easier (that means more profitable for the plumber) to use compression fittings instead.

 

[Flyfisher]

I doubt there's any real issue with embedding pipes in walls as such, after all it's fairly common to lay them within solid floors. We had this done in a previous house and the plumber (very 'old school' with decades of experience) sleeved the new underfloor central heating pipes with a sort of felt-like material. He explained this would allow the pipes to move slightly without causing any cracking of the floor. He used the same material when running pipes through floor joists to prevent them rubbing on the wood as they heated up/cooled down, which can often lead to a 'clicking' sound. It seemed to work perfectly well.

No, I'd suggest the issue is one of damaging the walls themselves, particularly if they are lath and plaster.

I also have reservations about hidden water pipes. I appreciate the aesthetic issues, but I've had to make numerous repairs to our plumbing and have been pleased when the pipework in question has been easy to work on without lots of associated building work. I know it's a personal thing but exposed pipework (within reason of course) doesn't really bother me too much.

 

[skier-hughes]

We are boxing all ours in with oak boards, along with some electricity cables as well.

 

[AMc]

We had a number of radiator pipes running down the walls and under the floors depending on the location - mostly gine in favour of underfloor heating. The pipes running down the walls weren't that bad but they were ugly. If it were me I would see if skier-hughes suggestion of boxing in surface mounted pipes (in corners) is practical. That will minimise the damage to the fabric and should keep the pipe work reasonably accessible to you in case of problems. Your plumber will probably like this idea if they don't have to do the boxing in
You should insulate the pipe work wherever it runs out of sight so you're not losing heat under the floors and into walls. It's common to believe the heat will rise into the room above but the void under the boards can be quite draughty and you may lose a lot of heat out where the joists meet the walls.

At the end of the day there are no magic ways to move hot water around your house you will have to make a compromise somewhere, the person best placed to make those calls is probably you because you'll be living with the solution long after your job is a distant memory to your plumber.
Work out where you want the radiators and then how you'd get the pipes to them then discuss it with the plumber - expect a bit of push back if it's not the easiest route - but stick to your guns, you'll be living with it for years.

 

[Merlin]

I echo the thoughts of boxing in pipework. I have had numerous experiences with hidden pipework which have been a nightmare to maintain, albeit in a modern house. I much prefer pipework to be visible so you can see if there is a problem immediately.

Do be wary though of chemical reactions between building materials and pipework. I am no expert, but concrete reacts with copper and will corrode the copper (according to my plumber) so copper should be sleeved if running through a concrete floor for example. As I say, I am no expert - so hope the experts on here will be able to offer better advice on which combinations to avoid.

 

[MatthewC]

I'd suggest the issue is one of damaging the walls themselves, particularly if they are lath and plaster.

I'd agree with that - there's a huge danger of making a lot of plaster loose, although the pipes could be hidden if you're re-doing a lath wall anyway (as I was, but I didn't hide the pipes as I too would like to see problems early).

I also had the same sort of issue with electrical cables - I once found the young electrician about to cut a chase in solid stone.

Matthew
(Smug in new old house, http://houseintheenchantedforest.blogspot.com/)

 

[chuckey]

If you are contemplating sinking the pipes into the plasterwork, insist that your plumber uses micro bore.
Frank