Central heating plumbing question?

  LastChip 12:31 01 Aug 2013

If we have any plumbers amongst our membership, I'd be grateful for some advice.

At the moment I have a property that has central heating (doesn't meet new flue regs) that needs a serious overhaul. It has concrete floors and at present, all the pipework is routed overhead in the bungalow roof.

As I'm in the process of gutting the place and essentially refurbishing it, I'd like to run the central heating pipework in the concrete floors. In years gone by, I've had leaks from the pump in the roof ruining a ceiling.

Is this a wise decision? And if so, what is the recommended (to comply with all current regs) way of doing it?

I don't want to bodge it, I want to do it properly.

  bumpkin 14:03 01 Aug 2013

I am assuming that it is gas. How old is the boiler and what type, do you have a hot water cylinder and how big is the property, it may be better to instal a new system.

  lotvic 14:24 01 Aug 2013

Here's a useful site for info, full of plumbers and advice (self build community) click here

This Thread click here (from 2007) is similar to your situation

  wiz-king 14:25 01 Aug 2013

Would be very expensive as the plumber would have to chase out a large groove in the floor unless you can get underneath it (suspended floor).

I would run copper or chrome plated tube round the skirting board and in a wooden box section around the door frame. I have mine in a 1" x 4" box (sides and face only)next to the door frame that takes 2 x 22mm pipes. You could always paint the tube to match the skirting if you wanted too.

  bumpkin 14:41 01 Aug 2013

LastChip, do you intend to do the work yourself?

  spuds 14:51 01 Aug 2013

I had an old property with concrete floors that required central heating pipes hidden out the way. First the concrete should be of sufficient thickness, allowing for any stress. The floors we had where 12" thick so grooving out a 2"x 2" groove with a disk grinder did the job. Pipework was then laid on a bed of sand, with further sand packing. Space was the left for a wooden tray to fill the space to floor level. This method provided access for any future maintenance.

Pity this question wasn't raised yesterday morning, because we had two central heating engineer's visiting, who are commencing work in replacing part of our central heating system at home to the more modern combi environmental friendly design. They will be returning back on Monday to start the work, so if I think about it, I will raise the question, regarding modern practises, and what would they consider!.

  Woolwell 14:55 01 Aug 2013

Copper pipes in concrete should be protected telegraph.

  woodchip 15:28 01 Aug 2013

Not read other than your post, but it is a bad idea to run lots or any pipes for that matter in Concrete, though I did lay my Main Gas Pipe from Meeter to Kitchen part in Concrete I did give room for it and rapped the pipe in Sillgas pipe tape, to stop lime attacking the copper as it will pinhole if in contact with cement. this as lasted some 47 years without problems

  woodchip 15:32 01 Aug 2013

It should have read Sylglas This stuff, its messy to put on

click here

  woodchip 15:41 01 Aug 2013


I have also had to replace copper pipe in the past that had pinholed where it touched wood. I had nearly 40 years self employed in building Industry so what I said above still stands. Not sure about Flue Regs now for a Boiler as they have changed since I finished working, just over 20 years ago and I was Corgi registered at the time, though my trade was Cabinet maker and Joiner. Seen it all Done it all including Rewiring houses, building Extensions and Dormers

  LastChip 18:18 01 Aug 2013

Thanks everyone for your replies.

Bumpkin, yes, I'm doing the work myself and it will be a new gas combi boiler. The old one was a Baxi and is now not only contravening current flue regs, but also becoming almost impossible to get spares for.

Think of it as a new installation.

Lotvic, thanks for those links - I'll take a look.

Wiz-king, as I'm retired, it won't be expensive - my labour is cheap :-)

Spuds, thanks for that. I know my water main (outside) is pretty much as you describe, in a sand filled box. Whether that is current practice, I'm not so sure. If you do get the opportunity to ask your professionals, I'd be most appreciative.

Woolwell, thanks for that link. I've come across this advise before and it seems logical and sound. Ducting the pipes make sense for any future maintenance and for thermal expansion.

Woodchip, many thanks for your expertise. I've also seen advice about taping the pipes with Denzo tape, which is probably similar. I'm not sure though, how that copes with the expansion and contraction of the pipes.

In old gravity systems, it didn't matter too much if there was a slight leak, as you'd probably never have been aware of it. The header tank would have automatically compensated and unless you saw a leak or dampness, you'd be none the wiser. With closed systems however, it becomes much more critical, as topping up (re-pressurizing) a system daily, can become a chore not to mention stopping the boilers operation.

As I said in my initial post, I want to do this properly and to comply with all the current regulations, so any further advice will be most welcome.

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

HTC U12 Plus review: Hands-on

Best Android emulators for Mac

TV & Streaming : comment regarder Roland Garros ?