Frozen Loft Tank in Farnborough or Chelsfield: What to Do

If the kitchen cold tap runs but the bathroom taps and toilet do not refill on a frosty morning, the pipe feeding your loft tank, or the tank itself, has almost certainly frozen. Turn the stopcock off clockwise, open the upstairs taps, and warm the frozen pipe slowly with a hot water bottle or towels soaked in warm water. Never use a naked flame. Before you turn the water back on, run a dry cloth along the pipe to feel for a split, because that is where the flood comes from.

Why it happens on the edge of the Downs

Farnborough village, Chelsfield and the houses out towards Downe sit higher and more exposed than central Orpington, on the edge of the North Downs. Many have the older cottages and larger houses with cold, draughty roof spaces, and nearly all of them have a cold water tank in the loft feeding the bathroom and hot water cylinder. The pipe that fills that tank comes up from the kitchen, through the house and across the loft, and the bit in the loft is the bit that freezes first.

Good loft insulation makes this worse, not better, if it is laid in the wrong place. Insulation laid right across the ceiling joists, including under the tank, keeps the warmth of the house out of the roof space completely. The loft then sits at the outdoor temperature, and so does your tank.

How do I know it is frozen and not something else?

• The kitchen cold tap works, but upstairs taps and the toilet do not refill. The mains is fine; the tank is not getting water, or the tank’s outlet is frozen.
• Nothing works anywhere. That points to the incoming supply. Check with neighbours and look at Thames Water’s postcode incident map before assuming it is frozen.
• The overflow pipe outside has an icicle on it. The overflow has frozen, and the tank may brim when the float valve sticks.
• It is the first morning below freezing, and it was fine yesterday.

How do I thaw a frozen loft tank safely?

1. Turn the stopcock off by turning it clockwise. In Orpington houses it is usually under the kitchen sink.
2. Open the bathroom taps, so that when the ice melts the water has somewhere to go and pressure does not build up.
3. Go into the loft with a torch and follow the pipe from where it comes up through the ceiling to the tank, feeling for the coldest section.
4. Wrap a hot water bottle, or towels soaked in warm water, around the frozen section, starting nearest the tap end and working back towards the tank.
5. Keep re-warming the towels. Expect it to take a while; slow is safe.
6. Once water starts trickling from the taps, run a dry cloth along the full length of the pipe and around the tank joints, feeling for any wet spot.
7. If everything is dry, turn the stopcock back on slowly and listen to the tank refill.

A hairdryer on a low setting can help if you keep it moving and away from water. A blowtorch, a heat gun or a fan heater pushed against plastic pipe can do far more damage than the frost.

What if a pipe has split?

You will often not see the split until it thaws, which is why Thames Water’s advice is to check with a dry cloth before turning the water back on. If you find a split or a wet joint, leave the stopcock off, open all the taps to drain the system, and switch off the immersion heater so the cylinder cannot heat up empty. If water has reached the ceiling below, switch that room off at the consumer unit and put a bucket under the damp patch. Do not push a hole through a bulging ceiling yourself.

How do I stop it happening again?

• Lag the pipes in the loft, including bends, joints and the overflow, with proper foam pipe insulation.
• Insulate the tank itself, with a jacket or insulated lid, and leave the loft insulation out from directly under the tank so a little warmth rises to it.
• Keep the heating on low through cold nights rather than letting the house drop right down.
• Open the loft hatch a few inches in a cold snap.
• Know your stopcock and check it turns before winter.

Farnborough and Chelsfield are not the only spots that feel it first. Up the hill at Biggin Hill, the highest parts of the borough get frost before the town centre does, and our guide to frozen pipes in Biggin Hill covers garages and outbuildings too.

What about the hot water?

If you have a hot water cylinder fed by the loft tank and the tank has run dry, avoid running the hot taps until the tank is refilling. If the cylinder has an immersion heater, switch it off while the supply is frozen. If your boiler shows a fault code in cold weather, it may be a frozen condensate pipe on the outside wall; that is a boiler matter, so check the manufacturer’s guidance or call a Gas Safe registered engineer, and if you ever smell gas call National Gas Emergency on 0800 111 999 first.

Need a plumber now?

If a pipe has split, water is coming through a ceiling, or you cannot get it thawed, Call 07868 281022. Tell us your postcode, what is leaking or not working, and whether the stopcock is off. We cover frozen pipes in Orpington and burst pipes across BR6, including Farnborough, Chelsfield and Green Street Green, and we agree the price with you before any work starts. More on the area on our Orpington page.