pipe lagging

[Mimmy]

I recently had a new downstairs loo fitted and the waste water pipe runs outside to the main drain.The pipe is a normal copper pipe and is lagged with that grey polystyrene type tube that fits over the pipe.but since the first frosts this week, the first few flushes have revealed that the water inside the copper pipe has frozen and it takes till about 11am to thaw.Is there anything I can do to the pipe to keep it from freezing? Is there a better form of lagging or some kind of extra insulation I can add to the pipe? any suggestions would be great as I am toilet training my 2 year old and if I flush the loo in the morning, the toilet backs up and he gets worried!Ta.

[MustafaTinkl]

Could you explain a bit more, please ? Normally the drain pipe from a downstairs toilet is a 4" plastic pipe which leaves the house underground and goes to a manhole and is almost impossible to freeze. Is your copper pipe a half inch diameter overflow from the cistern? Or have you had some sort of a pumped system installed?

[Mimmy]

it is a saniflo system which macerates the waste then pumps it through a copper pipe to the main drain,which in our case is through the wall, over the garage roof and into the main pipe.It is an add on we wanted in our extension and while going underground would be the best for the pipe, it would`ve meant digging up our kitchen floor! so we opted for this cheaper route.

[Tatty Rollox]

Understood. The only certain way out of the problem is to take off the existing insulation, wrap the pipe for its whole length with electric trace heating looped into a frost stat placed somewhere externally and then replace the existing insulation. Trace heating is simply a special electric wire that becomes warm (low temperature) when the frost stat switches it on. It does not cost a great deal, and "lasts forever". Can be an easy DIY job - just connect the trace heating wire to a 13 amp plug and plug into an existing socket outlet - or get an electrician in. Specialist electric stores stock trace heating and frost stats.

[MustafaTinkl]

Good Heavens !! From your other postings I thought that you were a Paintings and Arts person !! I hope that you won't mind me adding that if Mimmy does it as a DIY the electrical trace should be slowly wrapped around the pipe, each complete turn taking about 18" - 24" of pipe is sufficient. Otherwise, nothing else to add !! Best wishes.

[stanleyman]

This sounds as if it hasn't been installed properly. Ideally the pipe should rise high inside in the warm and then fall to drain completely with no water traps to freeze. Why can't it go through the garage where it would be warmer instead of over the roof, this is very poor practice?

Copper pipe can split if it freezes so I would repipe it all and route inside wherever possible with larger size 28 mm plastic pipe to avoid ice build up and to withstand any further possible freezing. If traps are avoided you shouldn't need any lagging at all which can also delay any thawing. Larger normal waste pipe and fittings can also be used to drain the downhill section with even less chance of ice build up inside the pipe.