Cold water tank in loft All aspects of plumbing questions and answers, help, tips and information

[St23]

I have got a cold water tank in the loft which feeds the cylinder in the bathroom which stores the hot water.

My concern is to do with tank and pipes freezing in the loft.

I have heard that when outside temps. fall below zero it is a good idea to open the loft hatch to allow warm air from the house to enter the loft and circulate round. Also some people apparently put electric fires directly under the loft hatch so that warm air is directed straight into the loft.


I was wondering if it is a good idea to minimise how much fresh outside cold water enters the header tank in the loft.

For example, if you minimise running any hot water taps in your house, then the hot water tank in bathroom will not need feeding from the loft tank. This would result in the cold water which is in the loft tank being, for want of a better word, old water and not the cold fresh stuff direct from outside.

Would my suggestion of keeping the old water in the loft tank keep things at a higher temp. and help to prevent any freezing?

[plumbbob]

I have heard that when outside temps. fall below zero it is a good idea to open the loft hatch to allow warm air from the house to enter the loft and circulate round. Also some people apparently put electric fires directly under the loft hatch so that warm air is directed straight into the loft.

You're not going to achieve anything useful by leaving the loft hatch open other than make the house colder. Any form of heating in or near the loft using open elements increases the fire risk.

Protecting header tanks is dead simple. Remove insulation below the tanks entirely and wrap them with at least 6 inches of fibreglass insulation. (The Space Blanket type is best because the covering prevents drafts.) If the tanks are on platform, make the insulation into a hollow column.

Pipes should be lagged and wherever possible run beneath the loft insulation.

Finally, always keep the house at a reasonable temperature and never let it fall below about 12 degrees without taking further measures in freezing conditions.