Private water supply frozen

[Softwaterhelp]

Hi, I hope someone can help - this is the second time its happened! Our soft water is pumped from the bore, up into a huge galvanised holding tank in an outbuilding, then pumped across (Grundfos MQ) to the 3 water storage tanks in the loft space of the house. The pipe that runs across from the outbuilding runs along the inside of a wall (10/12ft up) that joins the house with the outbuilding which is about 10ft long. The pipe is poly, sits within thick grey foam lagging then that sits within a plastic guttering pipe. We know the Grundfos is holding water as we have tested it. We have a heat lamp sat above it in this weather and an oiler fired radiator sat below the galvanised tank at 25C. The float/ball switches in the house loft are all free (it warm up there anyway as we have no insulation). Today have been wrapping hot towels, pouring boiling water over them constantly for three hours, to no avail. Should we strip off the guttering and lagging and try the hot towels and warm water again? If this works, how much and what type of external insulation should we provide to stop this happening in these extreme temps? -11 last night! Thanks for any advice!

 

[shorticus]

The only sure way of stopping your external pipes from freezing is by burying them, 750mm minimum 1350mm maximum, the ground at this depth stays at a constant temp all year round, 6-10 degrees.

If you're pouring water over insulation this may well exasperate the problem, the lagging may well absorb the water which will then freeze so back to square one. Keep the lagging as dry as possible, much of the insulating properties are down to the trapped air contained within so remove it before pouring hot water over the pipes.
To sort the problem in the short term will just take lots of effort and patience; in the long term you need to get those pipes buried.
Hope this helps.
Shorty